Infringement occurrences

NEW (5 August)

Infringement of the Class D Stansted Control Area 2 (CTA-2)

Date 3 June 2021
Aircraft Category Fixed-wing SEP
Type of Flight Recreational
Airspace / Class Stansted CTA / Class D

Met information

  • TAF EGSS 031056Z 0312/0418 24008KT 9999 SCT035
    TEMPO 0405/0418 7000 -RA
    PROB30 TEMPO 0406/0413 3000 +SHRA BKN014
    PROB30 TEMPO 0413/0418 SHRA RA BKN014=
  • METAR EGSS 031520Z AUTO 24008KT 9999 NCD 23/13 Q1019=

Air traffic control

The Air Traffic Controller observed a 7000 squawk on radar enter the southern part of the Stansted CTA near Epping indicating 2,200 feet. As the aircraft entered the CTA the Controlled Airspace Infringement Tool (CAIT) activated triggering an alert. The aircraft was seen to track northwest and then west, before leaving controlled airspace to the west of North Weald. The aircraft was then seen to squawk 5024 (Farnborough LARS North) and the pilot obtained a Basic Service. There was no impact on operations at Stansted Airport throughout period of infringement.

This incident took place when there has been a large decrease in the amount of Commercial Air Transport traffic operating at Stansted Airport and consequently there was no impact on the operation at Stansted. However, as traffic levels start to increase at airports a similar infringement would likely to result in disruption to arrivals or departures.

Figure 1


The pilot reported that they had planned to fly a return flight from Stapleford to practise navigation using VFR chart and dead reckoning, ahead of a future training course.  The route (Figure 2) had been planned with turning points at:  Cheshunt – Top Farm airstrip – Bassingbourn disused – Barkway VOR (BKY) – Panshanger disused

Figure 2

The route had been chosen as such as they were points of interest for a future CPL course. The flight was also to take a passenger flying who had never been in a light aircraft before; the passenger had a history of motion sickness experienced in other forms of transport.

On lining up on the runway the pilot carried out a check of the Direction Indicator but failed to correct a 5O error. The route planned started with an overhead departure from Stapleford. After departure from Runway 21L, the pilot followed the left-hand circuit and established a climb on the downwind leg. Shortly after turning downwind, the aircraft ahead in the circuit reported that they were returning to Stapleford for an immediate landing due to a low oil pressure indication. At the time there was an aircraft already on final and another aircraft late downwind nearing the base leg turn making a total of 4 in the circuit. The pilot of the subject aircraft decided the safest course of action was to continue climbing on the downwind leg and delay the turn overhead onto the planned heading of 290O for Cheshunt, and be at / above 1,800 feet when crossing the final approach path. This resulted in the turn onto the planned heading occurring approximately 1NM further northeast than planned, the turn itself was a gentle turn with 10O angle of bank, due to turning in the climb. The result of the two actions, lead to a track error of 0.6NM, with the actual track offset to the northeast, towards controlled airspace.

At the top of the climb, the pilot completed the after-take-off checks. These included a gross-error check of the route and heading where the pilot noted that ground features were seen as expected. During the checks the pilot noted that the passenger had been unusually silent since take-off. The pilot became concerned about their wellbeing and questioned how they were feeling, to assess if an immediate return to Stapleford would be required. The distraction led the pilot into failing to note and correct the offset actual track, caused by the late turn, and failing to correct the error in the DI. The pilot also recalls the wind appeared stronger than forecast, leading to a further 10o track error. Due to these errors, the pilot inadvertently entered CTA-2 one minute after the top of climb, south of VRP Epping.

 After checking if the passenger was ok, the pilot noticed that the picture, particularly the aircraft’s position relative to North Weald didn’t look correct. The pilot referred to their VFR Moving Map which was under their PLOG and noticed that they had infringed the Stansted CTA. As the aircraft was now close to the south-eastern boundary of the CTA, the pilot turned the aircraft onto a heading of 225oM to leave the CTA as quickly as possible whilst at the same time commencing a descent to increase groundspeed and expedite the exit of controlled airspace. (Figure 3)

Throughout the initial phase of flight, the pilot was communicating with Stapleford Radio due to still being in their ATZ.

Figure 3 Planned and Actual Tracks (entire Flight) in SkyDemon

Findings and Causal/Human Factors

The pilot carried out a detailed post flight analysis to the CAA as part of their MOR submission by reviewing the events leading up to the occurrence in terms of Threat and Error Management. In it they commented that they were previously unaware of the Take 2 guidance and noted that their initial planned tract was close to the CTA and “did not allow enough margin for error”.  The track planned for this flight was within 1NM of Stansted’s CTA 2. It would have been beneficial to have a more prominent landmark for the first turning point that would have made visual navigation easier. A less complex departure from Runway 21 could have been to climb straight ahead, considering noise abatement, and then turn to the River Lea reservoirs, this would allow a greater margin from controlled airspace in addition to using a more visible reference.

The pilot also reflected on how they now consider that there were too many aims and objectives for this flight, which unnecessarily increased their workload. Reflecting on the event, the aims of this flight could have been covered across two or three flights. Flying with passengers always introduces the threat of distraction and increased workload; this is heightened with one that has the potential to be unwell. In such circumstances, a simple route planned to minimise proximity to controlled airspace might give the pilot more capacity to provide reassurance and explanation of what is taking place during the flight and possibly result more enjoyable flight for the passenger.

Although current, the pilot also believed that skill-fade, and therefore reduced capacity, caused by the lockdowns and effect of the COVID-19 pandemic also was a contributory factor in this incident. Throughout the pandemic, most of their flying was focused practising visual circuits.

The pilot, on reflection, added that the first time practising the use of navigation using dead reckoning than a VFR Moving Map, after the most recent lockdowns, could have been conducted with a qualified instructor or fellow PPL pilot in the right-hand seat, rather than with a non-pilot passenger. An element of complacency may also have been evident. The circuit for Runway 21LH was the one most flown by the pilot and therefore the one with which they were most familiar with. However, due to a recent change to widen the Runway 03 downwind leg further to the northwest, the pilot has recently flown that as part of a ‘club check flight’. Having not flown  much due to COVID-19 related restrictions, this recent flight led to the ‘familiar’ picture developing when in proximity of the M25/M11 motorway junction along with a false sense of margin from the CTA when conducting the gross-error check at top of climb and in the vicinity of that reference point.  All the pilot’s formal training was to east or south of Stapleford, most noticeably over Kent and Essex, and most of cross-country flying done since obtaining their licence the pilot had been accompanied by a qualified pilot. The pilot felt when flying to a new area it could have been advantageous to be accompanied by a fellow PPL Pilot familiar with the points of interest and route.


Threat and Error Management

The pilot was faced with many threats such as distraction from both within the aircraft and from aircraft in the visual circuit, skill fade and normalisation from the majority of their recent, COVID-affected flying being in the circuit environment to the reciprocal runway from that in use on 3 June 2021.  Based on the proximity of the Stansted CTA and (although not a factor in this case, still a latent threat) North Weald operations, active TEM in the planning stage would have led the pilot to depart the Stapleford aerodrome environment as expediently and simply as possible through a southwesterly departure from Runway 21 with a turn to cross the M11 between Junctions 4 and 5 and then to the the River Lea thereby offering maximum separation from the Stansted CTA to the north and the London City CTA to the south.

However, once the decision was made to depart from the overhead, based on the developing traffic situation and increased workload from a rapidly changing plan, a reversion to using their VFR Moving Map may have offered the vital cues as to not only the proximity of controlled airspace but also as to the error in the, misalignement, albeit minor, of the DI.  Once clear of the ATZ and established on a heading for Cheshunt, the pilot could then have reverted to Dead Reckoning navigation with very little impact on their training objectives.

Thanks go to the pilot for providing such a comprehensive report into this occurrence.  Not only did they submit a report in the form of the online questionnaire at  but they provided the detailed report above on their lessons identified for the benefit of learning and development.

Focus on

11. Class D: Newcastle Control Area (CTA)

Infringement of the Class D Newcastle Control Area (CTA)

Date 23 April 2021
Aircraft Category Fixed-wing SEP
Type of Flight Recreational
Airspace / Class Newcastle City CTA / Class D

Met information

  • METAR EGNT 231350Z 10007KT 070V160 CAVOK 18/M01 QNH 1028
  • METAR EGTC 231220Z 12010KT 070V160 CAVOK 15/01 QNH 1028

Air traffic control

The Air Traffic Controller observed a 7000 squawk on radar with MODE S in the vicinity of Sunderland Harbour routing northbound indicating 2,000 feet. As the aircraft approached Tynemouth it was seen to have commenced a descent to 1,600 feet. A blind call was made to try to establish contact and intentions, but no reply was received. As the aircraft continued north and approaching the Blyth windfarm it was observed to climb to 1,800 feet. Further blind calls were made to the aircraft with no response. The aircraft left the CTA and was observed climb to 4,000 feet and was tracked on radar to the Scottish borders where the contact was lost. Scottish FIR was asked to maintain vigilance in case the aircraft made contact. Scottish FIR called back to confirm that no contact had been made. There was no impact on operations at Newcastle Airport throughout period of infringement.

Figure 1

Figure 1


The pilot reported that they had planned to fly from Cranfield aerodrome in Bedfordshire to an aerodrome in southeast Scotland having collected a family member. The route had been planned on a VFR Moving Map as follows:

Cranfield – Sackville Farm – Stilton – The Wash –Sunderland Harbour – 5NM northeast of Morpeth – Scotland.

The route was intended to be flown at around 165 knots with a climb to 5,000 feet until approaching Newcastle. As the passenger was not keen to fly over water, the pilot intentionally planned to fly under CTA-2 to be closer to land followed by a climb up to around 3,000 feet before starting a final descent into their destination aerodrome. The route was selected to route to the east of the military aerodromes in Lincolnshire, to the west the military danger areas of Holbeach (EG D207) and Donna Nook (EG D307) and to the west of the Teesside CTR/CTA before turning left for the destination once north of the Newcastle CTA. The pilot stated that is was a route that they were very familiar with and commented that, on the return flight from Cranfield in the middle of afternoon, it was very thermic. As they approached Newcastle and heading out to sea they descended to route beneath the higher CTA-3 (with a base of 3,000 feet) and then again to route beneath CTA-2. At that point they started to experience thermic activity. The pilot commented that as they approached the offshore wind farms at Blyth they were being “pushed up slightly”; they were, however, unaware of the infringement. They also added that it was possible that the QNH at Newcastle may have been different to that set as they were still flying on the QNH issued for their departure at Cranfield (180NM to the south).

The pilot did not plan to communicate with air traffic control along the route and while they did consider contacting Newcastle to request a CTR transit overhead they decided against it as they didn’t want to inconvenience them.

Figure 2

Figure 2

Findings and Causal/Human Factors

The infringement occurred due to an inadvertent climb into the CTA due to thermic activity. Whilst the pilot reacted quickly to the climb, the response was insufficient to prevent the aircraft entering controlled airspace. However, a number of valuable lessons emerged from this occurrence. Many of the lessons that might be learned from occurrences can be relevant to us all and often may not be new.

Threat and Error Management

One way of learning from occurrences offered within the ASI narratives is to view them in the context of Threat and Error Management (TEM) which is an essential part of the planning and preparation for every flight, whether it be a local flight or a cross-country landaway. So what were the key Threats to this flight?



The pilot flying the circa 300 NM route from Cranfield to Scotland had to consider a multituide of airspace structures en-route, including Class D CTA’s and CTR’s, active Danger Areas, Aerodorome Traffic Zones (ATZ’s), Military Aerodrome Traffic Zones (MATZ’s) as well as winch launch glider sites, unlicenced minor aerodromes, parachute sites and unusual aerial activity tactically notified on the day by NOTAM. The pilot was using a VFR Moving Map which not only would have given the pilot enhanced situational awareness as to their location but also timely alerts to airspace and notifies unusual aerial activity. When planning for the flight, it is good practice to also plot the route on a paper chart. By doing this, a “single view” of the route and airspace is available, more than when ‘rubber banding’ the route electronically between waypoints. In addition, having a chart ‘marked-up’ acts as a perfect mitigation to the Threat of a tablet or display failure when solely relying on a VFR Moving Map. It is also possible to print out a “route chart” from some moving map software (on a long route this can be several pages). Having backup electronic moving map devices available, provides additional threat management. Having an alternative chart available (in whatever form – electronic or paper), mitigates the threat of the failure of a primary use VFR Moving Map.


Any time that you fly with a passenger, irrespective of who they are and how many times they have flown before, they need to be managed to ensure that they do not pose a distraction from the priority tasks of aviate, navigate and communicate. In this situation, the pilot knew that the passenger was nervous when flying over water, so this needed to be considered, as the pilot’s attention may be drawn towards providing reassurance and away from the various tasks of operating the aircraft.


In this particular case the pilot was fortunate that the QNH values for the both Cranfield and Newcastle were the same for the duration of the flight; however, this is not a usual situation. As we all know, weather conditions often vary across the UK day by day and hour and by hour. Together with temperature, cloud and visibility, changes in air pressure (QNH) also occur. Such differences in QNH can be experienced especially when areas of low-pressure approach and transit the UK but can also occur when areas of high pressure build near to the UK. In general, if strong surface mean winds occur this is a sure sign of large pressure gradients which can result in large changes in pressure across Altimeter Setting Regions (ASRs). Typically, in this case in April differences in QNH of up to 10 hPa between two ASRs can be experienced (this represents a difference in altitude of ~ 270 feet). Although such significant differences in QNH are infrequent, when they do occur and the pilot hasn’t kept altimeter settings up-to-date, the implications can be significant in terms of the awareness of the height the pilot should be flying at and therefore presents a potential significant risks with respect to maintaining separation from and avoiding infringement of particular airspace, and also terrain clearance. So, in such conditions of changing QNH, particular care should be taken to ensure altimeter settings are up to date and relevant for the base of controlled airspace that is being operated underneath, i.e. Is the airspace above the route in reference to a QNH or a Flight Level and is your altimeter set correctly, to reflect this?

Version 3 of the Skyway Code (CAP1535) provides a very helpful description of the types of altimeter settings and altimeter setting procedures, (pages 86 and 87) and guidance to pilots on avoiding air infringements with respect to altimeter setting (page 132): ‘When considering your altitude also ensure that you are on the most appropriate altimeter setting for the area in which you are flying. Remember that the Regional Pressure Setting offered by some ANSP is the lowest forecast pressure setting for an altimeter setting region. Care must also be taken to note where the base of CAS changes between an altitude and a Flight Level.’

Examples of large pressure gradients over the UK created by both nearby low pressure and high-pressure systems in springtime (and therefore large differences in pressure between ASRs) can be found below. In these cases, the pressure gradients are basically north-south, but pressure gradients could be aligned in any direction to create large QNH differences across some ASRs.

Low pressure example: 11 April 2016, pressure varying from about 1008 hPa in south Barnsley ASR to just over 1016 hPa in north Tyne ASR (Figure 3).

Figure 3

Figure 3

High pressure example: 29 March 2020, pressure varying from about 1036 hPa in south Barnsley ASR to just over 1046 hPa in north Tyne ASR (Figure 4).

Figure 4

Figure 4


This was route flown by the pilot on many previous occasions. It is possible that the practice of flying this route had become a routine task and therefore, a general relaxation of vigilance may have crept into their human performance and signals of Threats may have missed. An indication of this is that the pilot was unaware of the infringement indication; it is also possible that they only saw, on the aircraft instruments, what they expected to see. Every flight should be treated as if it is the first time that the flight is being made, from planning through to execution; the weather, NOTAM and traffic situation are but a few external factors that will vary each time along with human factors that affect performance.


Obtain a Crossing Clearance

The pilot could have mitigated the risks of an airspace infringement and of a nervous passenger becoming more distressed by low-level turbulence, by maintaining their initial altitude and requesting a VFR transit of the CTA and CTR.

‘Take 2’ (or more)

One method of avoiding advertantly infringing airspace is to provide an element of separation from controlled airspace; this can be achieved by incorporating the Take 2 guidance into the plan (where possible, maintain 2NM laterally or 200 feet vertically clear of notified airspace). However, in certain circumstances, it may be sensible to increase that distance based on a number of factors such as thermic activity, the speed of the aircraft and how easy it has been previously in the flight to maintain straight and level flight. However, when attempting to transit below a CTA with a low base, it is also important to consider unintended consequences of descending to fly lower. When flying with a nervous or apprehensive passenger, the act of flying lower and potentially into more turbulent air, an already concerned/apprehensive passenger may become more distressed leading to even greater distraction for the pilot.

Use a Frequency Monoitoring Code (FMC)

If the decision remained to fly below the CTA and ‘Taking 2’, it would have been good practice to use the relevant FMC for the area (in the case of Newcastle it is 3737 and Newcastle Approach on frequency 124.380 MHz) rather than squawking conspicuity. Whilst pilots will not be in receipt of any service under UK FIS, the use of an FMC helps in preventing and mitigating the consequences of airspace infringements. This works by allowing the ATSU to be aware of aircraft that are on their frequency and enables it to quickly contact the pilot of any aircraft that may be infringing (or are likely to infringe if capacity permits) controlled airspace, thereby allowing an actual or potential infringement efficiently to be resolved quickly, before it becomes a more serious incident. Subject to workload, ATC will often endeavour to provide a timely warning if an aircraft looks like it will infringe but there can be no guarantee that pilots will always be warned if controlling capacity does not permit. A chart of the FMC areas is in the UK AIP at ENR 6-80 and in AIC Y085/2020; Both the CAA 1:500k and 1:250k VFR Charts have the relevant frequency and FMC annotated on the chart and in addition, some VFR Moving Map apps provide that information on the display/radio tab. Even if your aircraft is not equipped with a transponder, it remains good practice to monitor the relevant frequency if an air traffic service is not requested as ATC will make ‘blind transmissions’ to aircraft that they believe may be infringing.

Focus on

10. Class D: London City Control Area (CTA)

Infringement of the Class D London City Control Area (CTA)

Date 11 April 2021
Aircraft Category Fixed-wing SEP
Type of Flight Recreational
Airspace / Class London City CTA / Class D

Met information

  • TAF EGKB 111655Z 1118/1121 30007KT 9999 SCT045 PROB30 TEMPO 1118/1121 6000 -SHRA=
  • METAR EGKB  METAR EGKB 111650Z 30007KT 250V350 9999 SCT047 06/M04 Q1020=

Air traffic control

The Air Traffic Controller (Thames Radar)

reported that a Commercial Air Transport (CAT) aircraft was on final approach to Runway 27 at London City Airport and under the control of the Tower Controller when an aircraft squawking 7047 (Biggin Hill conspicuity) was observed to the southeast of London City Airport heading towards the CTA at 1,800 feet.

The inbound aircraft was allowed to continue on the approach to see if the traffic in Class G airspace was going to turn away.  As the aircraft got closer to the CTA is became apparent that it would infringe the CTA (base 1,500 feet).  Rather than giving avoiding action to the IFR CAT aircraft in a critical phrase of flight  (through a phone line to London City Tower), the controller elected to use the priority line to Biggin Hill Air Traffic Control  to have the infringing aircraft turn east immediately to vacate the CTA. As a result of the right turn, separation between the 2 aircraft was maintained.

When facing infringement traffic scenarios controllers are faced with prioritising actions to resolve the situation as quickly and as safely as possible whilst continuing to manage the routine traffic situation.  Initiating such action takes time, increases workload and reduces the controller’s ability to undertake additional tasks which may not be immediately obvious to other pilots on the frequency at the time.

Figure 1 London City CTA


The pilot reported that they had planned the route to fly from West Tisted in Hampshire to Rougham in  Suffolk as follows:

  • West Tisted – VOUGA (3NM ENE of West Tisted) – LUXIV (2NM west of Haslemere) -Biggin Hill Airport – Dartford – Chelmsford -Rougham (Figure 2)

Figure 2 The planned route

The route had been planned on a VFR Moving Map and the pilot was also carrying a VFR 1:250,000 chart.   The pilot was I was returning to Rougham from a short visit to West Tisted. To the south of Bordon, the pilot contacted Farnborough to obtain a Basic Service as they routed to the northeast and under the Farnborough CTA at between 1,800 and 1,900 feet. They routed slightly north of their track to maintain north of the Gatwick CTA ( base  1,500 feet) . In the vicinity of  Epsom they were transferred to Biggin Approach and were issued a squawk and placed under a Basic Service. The route was the same as that completed earlier in the day (in reverse) with no issues. On passing north abeam Biggin Hill Airport, the pilot was  directed to call when passing Swanley. The pilot’s concentration was, at that time, focussed on identifying Swanley from their chart when they received an audible warning from their VFR Moving Map  that they were infringing the London City CTA. At the same time, Biggin Approach called and directed them to turn to the east immediately. The pilot had had already begun to descend quickly and they also turned to the East. On reaching 1,300 feet, the pilot turned back toward Dartford and completed, uneventfully, the remainder of the flight.

Figure 3

Findings and Causal Factors

This infringement resulted from 2 main factors when transiting in complex airspace near 4 London airports and the busy GA aerodrome at Redhill.   The first aspect was the Human Factor of Cognitive Tunnelling.  This occurs when the brain is involved in the processing of highly critical task-relevant information, with limited or no processing of secondary information that may also be important to the task.  In this case, the pilot was focussing on trying to visually locate Swanley and did not see the relevant data that was a being displayed on their VFR Moving Map which would have been the displaying of a visual alert as to the proximity to the London City CTA , the physical position of the aircraft on the Moving Map and the audio alert associated with the proximity warning. This type of human factor is common in many airspace infringements when operating in the single-pilot mode that underpins the majority of Sport and Recreational GA flying where Crew or Team Resource Management cannot be employed as a defence.  In addition, in many infringement occurrences where Moving Maps are used, pilots often report a failure to hear alerts.  Whilst in some cases this may be due to the equipment’s audio alert being masked by engine noise, it is also possibly due to a degradation in hearing during stressful situations.  At times of heightened stress, hearing can be degraded as the adrenaline produced by the body in response reduces or even stops circulation in the inner ear.

The second aspect was much more associated with lapses in Threat and Error Management in the planning stage and related to the route selected. The pilot, whilst using a VFR Moving Map to enhance situational awareness, was faced with a complex 107NM route. The first 55NM (to the point of the airspace infringement) included a large number of Threats associated with airspace structures that either had to be avoided or subject to obtaining a  clearance/permission to enter. In addition, in the relatively narrow corridor between the London/London City  and Gatwick controlled airspace, there is a latent Threat posed by other aircraft in relation to mid-air collision. The numbers in the list below relate to those plotted on Figure 4.

  1. Farnborough CTA-4 with a base of 2,500 feet (LTMA directly above).
  2. Gatwick CTA with a base of 1,500 feet (LTMA directly above).
  3. Heathrow CTR -Gatwick CTA corridor with potentially high volumes of other aircraft in a relatively narrow, low volume of Class G airspace with the LTMA directly above from 2,500 feet. This area is frequently used by traffic to/from Redhill, Fairoaks and Biggin Hill including instructional flights and those by solo-students where workload affects lookout.
  4. Kenley Gliding Site with winch launching to 2,600 feet amsl.
  5. Warlingham (Kennel Farm) Hang-gliding with winch launching to 2,600 feet amsl.
  6. Biggin Hill ATZ.
  7. Biggin Hill IAP laying outside controlled airspace (annotated by the ‘feathers’ on the chart) and
  8. London City CTA with a base of 1,500 feet (LTMA directly above).

When considering a route, it is essential that effective Threat and Error Management is incorporated into the plan. By avoiding the Heathrow CTR – Gatwick CTA corridor and routing from:

  • West Tisted – Petersfield – Burgess Hill – Uckfield – Tunbridge Wells  – The QEII Bridge/Dartford

and incorporating the guidance of ‘Take 2’, the pilot would have added a maximum of just 17NM to the overall flight distance  and approximately 10 minutes to the flight time but would have Treated (managed) all 8 Threats shown in Figure 4.

It is very difficult to know exactly where you will become distracted; none of us have the benefit of foresight but with effective TEM, one can anticipate when you may succumb to increased workload, heightened stress and a greater risk of distraction. Hindsight? No; active TEM? Yes. By looking at the chart extract in Figure 4, one can see that that the 30NM section from abeam OCKHAM VOR (OCK) to the River Thames will stretch even the best pilot’s lookout and capacity.

Figure 4

Focus on

  • Threat and Error Management – Read Threat & Error Management
  • Use of Moving Maps – ‘alert fatigue’ and use of climb/descent waypoints.
  • Take 2 – Read TAKE2

09. CIass A: Class A London Terminal Control Area

Infringement of the Class A London Terminal Control Area

Date 19 June 2020
Aircraft Category Fixed-wing SEP
Type of Flight Recreational
Airspace / Class LTMA / Class A

Met information

  • METAR EGLL 191450Z AUTO 21014KT 9999 SCT033 SCT039 BKN046 19/11 Q1015 NOSIG=

Air traffic control

The Air Traffic Controller (Farnborough LARS West) reported providing air traffic services to five aircraft with a low to medium workload. The controller noticed an Airspace Infringement Warning (AIW) alert activate 3NM east of Wycombe Air Park/Booker aerodrome (Figure 1).

The AIW was associated with an aircraft squawking the Farnborough Frequency Monitoring Code (FMC) of 4572 indicating 3,300 feet where the base of the London Terminal Control Area (LTMA) is 2,500 feet (Figure 2).

The controller called the pilot who immediately replied. The pilot was then advised that the base of controlled airspace in their location was 2,500 feet. The pilot replied staying that they were descending.  At the same time the Heathrow Special VFR controller called the Farnborough West controller to alert them of the event and was told that the subject aircraft was descending. On leaving controlled airspace, the controller obtained a level check from the pilot and verified that the aircraft’s MODE C was accurate.

Chart showing where the AIW alert activated, east of Wycombe Air Park/Booker aerodrome

Figure 1 An AIW alert activated east of Wycombe Air Park/Booker aerodrome

Chart showing that the base of the London Terminal Control Area (LTMA) is 2,500 feet

Figure 2 The base of the London Terminal Control Area (LTMA) is 2,500 feet


The pilot reported that they had planned a VFR cross country flight from Dunkeswell aerodrome in Devon to Earl’s Colne in Essex. It was the pilot’s first lengthy cross-country flight since the UK had entered the first COVID-19 lockdown in March 2020. The weather was reported as CAVOK and the route planned to be flown was:

  • Dunkeswell – Frome – Welford Discussed aerodrome – overhead Wycombe Air Park/Booker aerodrome  – overhead Elstree aerodrome – LAM/ overhead Stapleford aerodrome – west of Chelmsford VRP – Earl’s Colne aerodrome (Figure 3).

The route had been planned on a VFR moving map to route to the north of the London CTR/TMZ and was one that the pilot had flown many times.

Chart showing the planned route

Figure 3 The planned VFR route

As the weather conditions were good the pilot wanted to fly as high as possible to maximise the views from the cockpit.  They flew at 2,500 feet until Welsford (7NM southwest of the Compton VOR (CPT)) when they commenced a gradual climb to 3,300 feet, reaching that altitude overhead Wycombe Air Park/Booker aerodrome.  The pilot commented that when using their VFR moving map, there were so many different alerts, most of which they felt were unnecessary, which led to them to habitually cancelling the warnings.

The pilot also stated that they used a personally prepared Flight Preparation checklist comprising five sections:

  1. Departure airfield;
  2. Arrival airfield;
  3. En-route;
  4. Flight plan (VFR only); and
  5. Survival/equipment.

In that list, “Altitudes” was included in the En-Route section only.  After the occurrence, the pilot has added “Planned Altitudes” item to the “Flight Plan” (VFR Only) section. A copy of the checklist used at the time of the occurrence is at Table 1.

In addition, as soon as they were made aware of the occurrence, they submitted a detailed report and carried out effective post-flight analysis which resulted in revisions being made to their own check list to mitigate the risk of a recurrence.

Copy of the pilot's flight preparation checklist

Table 1 Flight preparation checklist

Findings and Causal Factors

The pilot had formulated a sound primary plan relating to the route. However, insufficient consideration was given to the vertical portion of the route. The pilot’s own admission was that the planning of the flight was rushed and therefore incomplete. An essential aspect of planning is incorporating effective Threat and Error Management.

When planning it is good practice to break down the route into sectors/segments between waypoints. One of the threats which will affect many flights is airspace, whether that be controlled airspace, ATZ, TMZ /RMZ, restricted or prohibited airspace, danger areas, glider sites, parachute sites or minor aerodromes.

A threat that frequently emerges when using VFR moving maps and ‘rubber-banding’ the route between waypoints is that detailed analysis of what lies between the waypoints can be easily missed. By reviewing each sector/segment in detail, you can assess the lateral route and then plan for the maximum altitude to be flown (the lower limit of vertical controlled airspace less 200 feet if possible as part of Take 2) along with minimum safe altitudes.

If using a paper chart, it is good practice to write the maximum planned altitude alongside the MSA calculation or annotate it on your PLOG. If the route is too complex, or unachievable vertically, you may need to consider changing the track. Once those sectors/segments are finalised, it is then a good idea to insert additional waypoints along the route to indicate points at which a descent or climb can commence, in order to pass under a CTA or perhaps under lowering ‘steps’ in a TMA,  or where  it is possible to climb higher as the CTA/TMA ‘steps up’; remember to incorporate the Take 2 guidance into these points.

In addition, as the pilot had flown the route “many times”, there may have been an element of inadvertent complacency leading to a loss of situational awareness. The human factor of complacency has been equated with over confidence, a state of confidence plus contentment, low index of suspicion and unjustified assumption of satisfactory system state. In addition, when using a VFR moving map as the sole source of navigation, the pilot in essence becomes a system monitor.  In 1998 Dr Tony Kern (author of books on human performance, including the ‘Plane of Excellence’ and the trilogy of ‘Redefining Airmanship’, ‘Flight Discipline’, and ‘Darker Shades of Blue’) explained that ‘‘as pilots perform duties as system monitors they will be lulled into complacency and lose situational awareness”. This may be categorised as automation-induced complacency.

Another threat that was not managed in this occurrence was the pilot’s incomplete reaction to the aural and visual alerts that the VFR moving map was providing.  In many airspace infringements where the pilot was using a VFR moving map they had succumbed to alert fatigue.

The pilot commented that along the route “combine all the different alerts received on [the  moving map] (sic), most of them are perhaps a little too sensitive, resulting in multiple warnings that are unnecessary, leading to a habitual cancelling of the warning.” A typical human reaction is to think “yes I know that” or “that does not apply to me” with many of the alerts. The more frequent that happens, the rapid ‘cancellation’ of an alert takes place to ‘clean-up’ the display; inevitably, the one alert that was needed to break the chain alerting to the LTMA controlled airspace ahead was missed. This is an example of a gradual process by which the unacceptable becomes acceptable in the absence of adverse consequences; this is known as normalisation of deviance.

Post-flight analysis comment

This is another example of an airspace infringement occurring due to lapses in effective planning and ineffective use of a VFR moving map. A number of Human Factors and Threats and Errors led to this event. They always exist, often in the latent form, but they have the potential to emerge and develop into an incident or accident.

In this occurrence, the pilot is to be commended for their use of a VFR moving map and a Frequency Monitoring Code (FMC). The pilot decided, based on the prevailing meteorological conditions, that an air traffic service was not required. But by using an FMC the pilot enabled the expedient  resolution of the occurrence to which they too responded promptly.

ANSPs with an FMC encourage pilots to ensure the appropriate codes are displayed with the correct frequency monitored when an air traffic service is not required within the  published geographical area.

Focus on

08. Class D: East Midlands Control Area 2 and winch-launch site overflight

Infringement of the Class D East Midlands Control Area 2 and overflight of active winch-launch glider sites

Date 11 October 2020
Aircraft Category Helicopter
Type of Flight Recreational
Airspace / Class East Midlands / Class D

Met information

  • TAF EGNX 111102Z 1112/1212 31007KT 9999 SCT020
  • METAR EGNX 111450Z 31007KT 270V340 9999 BKN035 12/05 Q1026=

Air traffic control

The Air Traffic Controller (Radar Director) reported vectoring a Commercial Air Transport aircraft on left base for and ILS approach to Runway 27 when an aircraft squawking 7000 was observed entering CTA-2  indicating between 2,000 and 2,300 feet on MODE C (Figure 1). The CAT aircraft, descending from 4,000 feet to 3,000 feet was instructed to stop its descent and turn onto a north-westerly heading.  The aircraft levelled at 3,500 feet and passed approximately 4NM laterally and 1,000 feet vertical from the infringing aircraft.

The Air Traffic Controller (Radar/LARS) was operating in a bandboxed configuration (two frequencies combined, carrying out the functions of radar and LARS) and experiencing high workload due to multiple aircraft free calling East Midlands for air traffic services in Class G airspace and transits of controlled airspace.  The infringing aircraft’s pilot established communications with LARS one minute and 7 seconds prior to entering controlled airspace but, due to the high workload, the pilot was instructed to standby and remain outside controlled airspace.  The aircraft was then issued with a squawk, identified and instructed to vacate the CTA.

Chart showing CTA-2

Figure 1: Aircraft squawking 7000 was observed entering CTA-2


The pilot reported that they had planned the route to fly from a private site in North Yorkshire to Leicester via the Doncaster-Sheffield Airport overhead (Figure 2).   

Chart showing planned route

Figure 2: Planned route – North Yorkshire to Leicester via the Doncaster-Sheffield Airport overhead

The route had been planned on a VFR Moving Map and the pilot was also carrying a VFR 1:500,000 chart.  After the Doncaster-Sheffield Airport overhead, the route was planned to be flown through, or underneath, the East Midland CTA. However, whilst under Radar Control from Doncaster Radar and having been given clearance to route through their overhead, the pilot was asked instead to route to the East of their intended route. The pilot was almost east abeam Retford/Gamston aerodrome by the time they were cleared to continue on their intended route. At that stage, the pilot determined that they could now track direct to Leicester aerodrome east of the East Midlands airspace.

However, the pilot still wanted to obtain a Basic Service, but the frequency was so busy that it took some 10 to 15 minutes to get their first transmission made. Whilst in the ‘queue’ to receive a squawk from East Midlands Radar, the pilot realised that the Langar parachute drop zone was active. Eager to avoid the drop zone and keep an adequate lookout for the unusually large amount of traffic operating in the area, unfortunately the pilot allowed their track correction to the west to continue for too long before turning South. This caused them to inadvertently enter CTA-2 whilst at 2,000 feet. On being contacted by the LARS controller, the pilot immediately corrected their course eastwards and reduced their altitude as quickly as was safely possible, in order to vacate the CTA. The track flown is shown in Figure 3.

Chart showing the track flown

Figure 3: Track flown

Findings and Causal Factors

The pilot had formulated a sound primary plan to incorporate VFR transits of 2 volumes of controlled airspace: the Doncaster-Sheffield controlled airspace complex and the East Midlands CTA-2. However, lapses in planning result in no alternate plan (PLAN B)  having been formulated in the event that a transit of either or both volumes of controlled airspace was not approved. When the pilot was issued a vector to route to the east of the Doncaster-Sheffield CTA they were now flying in an area that they had not planned to be in and had not considered from a Threat and Error Management perspective. As the pilot flew south, they overflew the following 2 winch launch glider sites at between 1950 feet and 2000 feet amsl: Darlton which is notified as operating sunrise to sunset (HJ) with cable launching up to  2,200 feet amsl and Syerston which is also notified as operating sunrise to sunset (HJ) with cable launching up to 3,300 feet amsl.   In addition, the pilot flew through the Syerston Aerodrome Traffic Zone which, for the purposes of Rule 11 was notified in the UK AIP ENR2.2 (Other Regulated Airspace) as between 0730 hours and 15 minutes after Sunset from the surface to 2,231 feet amsl (Figure 4); on the date of the flight,, gliding was taking place at the aerodrome.

Extract from UK AIP ENR2.2

Figure 4: UK AIP ENR2.2

It is essential that whenever a flight is planned, an alternate route is considered by applying Threat and Error Management (TEM). Whilst air traffic control will make every effort to provide a crossing of controlled airspace on your requested route, it is good practice to anticipate that may not be the case.  In formulating a ‘PLAN B’ it is essential to consider airspace structure and activities in the Class G airspace surrounding the controlled airspace that you plan to transit.  As part of that planning, and application of TEM it is essential that you use the planning equipment to its optimum to consider all threats and risks.  For example, on a paper VFR chart, winch launch glider sites are depicted with a blue circle and a G with figure in thousands of feet amsl to which the cable may extend e.g. G/3.3 signifying 3,300 feet.  On the VFR Moving Map equipment that the pilot was using, the same area is depicted with a glider symbol but no maximum cable altitude in immediately visible. (Figure 5).

VFR moving map view

Figure 5: VFR Moving Map

To establish the winch launch altitude, a pilot is required to press on the location and review the tab which appears on the screen. The information is shown in the list containing waypoints, airspace and radio services and in the vertical extent to the side showing the elevation of the site, the maximum cable altitude and any other airspace such as an ATZ (Figure 6).  This information is also contained in the UK AIP at ENR 5.5 (Aerial Sporting and Recreational Activities).

VFR moving map waypoints list

Figure 6: Winch launch altitude is shown in the waypoint list

It is important to note that any depiction of altitude relating to glider sites refers only to the maximum altitude of the cable.  Glider activity can be expected to take place in the same area as either aero-tow or free-flight/soaring activity above the annotated altitude. 

The pilot’s decision to route to the west of Langer and towards the East Midlands CTA also indicated lapses in effective situational awareness associated with ineffective TEM and pre-flight planning .  The pilot commented that the East Midlands frequency was busy with multiple aircraft requesting a service. The pilot had already seen parachutes in the air from the jump aircraft at Langer.  The wind at the time was from the west/northwest so the parachutists would have exited the aircraft to the west of the Langer drop zone.  The pilot became fixated on maintaining an effective lookout as they were aware, based on how busy the East Midlands LARS controller was, that there were multiple aircraft in the vicinity of their track between Langer and East Midlands airport. This fixation resulted in Cognitive Lockup (the tendency of pilots to deal with disturbances sequentially) where they focused on the task of lookout and became reluctant to look at their Moving Map which would have not only given an alert as to their proximity to controlled airspace but would also have indicated that the pilot could have descended to at or below 1,500 feet and routed safely and effectively below CTA-2.  The decision to switch or not to switch tasks may be influenced by a misperception of the expected benefits. This decision-making bias may mean that the benefits of switching have to be significant before the decision to switch is made. Furthermore, if an individual feels that the ongoing task is almost complete, they are more likely to stick to the ongoing task even if the new task is more urgent.

In addition, by making the decision to avoid Langer to the west (as the destination of Leicester lies to the southwest) the pilot was flying into a higher workload environment. A turn to the east would have added no addition distance to the flight and would have taken the pilot into less complex airspace and away from a traffic ‘funnel area’. In addition, it would have reduced cockpit workload, due to less radio telephony work.  In their wider planning and decision making, had they considered applying the Take 2 guidance (Figure 7) of maintaining 2NM laterally from and/or 200 feet below controlled airspace, they may have altered their plan as they approached Langer to route into the more benign airspace to the east.


Figure 7: Take2

Post-flight analysis comment

Having an effective PLAN B will always put you, as a pilot, in a good position when external factors, such as weather, ATC restrictions or other traffic, influence your flight. It is relatively simple to make a sound plan and a backup plan or series of plans for each volume of airspace you fly in, or close to, and to incorporate effective Threats and Error Management  in the various plans.  It is, however, much harder to identify the onset and then override many of the Human Factors, such as Cognitive Lockup or Confirmation Bias that result in airspace infringements. That said, by being aware of their existence, it is possible to manage them; for example, a greater understanding of the risks in a particular sector of a route may also reduce the likelihood of cognitive lockup. In a multi-pilot operation, separation of tasks and roles between pilots, for example, by the captain passing control of the aircraft to the first officer while the captain deals with the malfunction, reduces the risk of both pilots fixating on the malfunction.  Had their  VFR Moving Map also been coupled to an Electronic Conspicuity (EC) device,  this may have provided some situational awareness of participating EC traffic along with a timely warning of the proximity of controlled airspace.

Focus on

British Gliding Association poster - Winch cables can kill

Figure 8: Winch Cables Can Kill!

07. Class D: Birmingham Control Area

Infringement of Class D – Birmingham Control Area

Date 7 October 2020
Aircraft Category Fixed-wing SEP
Type of Flight Qualifying Cross Country PPL Training Flight 
Airspace / Class Birmingham CTA / Class D

Met information

  • TAF EGBB 070459Z 0706/0806 26009KT 9999 SCT030
  • TAF EGBB 071056Z 0712/0812 27010KT 9999 SCT030
  • METAR EGBB 071150Z 28009KT 240V320 9999 FEW035 BKN044 13/06 Q1013=
  • METAR EGBB 071220Z 27011KT 240V310 9999 BKN042 14/06 Q1013=
  • METAR EGBB 071250Z 28012KT 9999 BKN044 14/05 Q1013=

Air traffic control

The Air Traffic Controller reported being alerted, by the Airspace Infringement Warning tool, to an aircraft entering the Class D CTA-2 to the east of Coventry aerodrome at 2,500 feet, squawking 0010. The aircraft is seen to track east to west at the boundary with CTA-4 (figure 1). Due to another aircraft in the vicinity it takes a moment to interrogate the radar to establish, using MODE S, the identity of the infringing aircraft.  The aircraft, having left controlled airspace tracked south and remained outside of controlled airspace until landing at Wellesbourne Mountford aerodrome.

Figure 1: Aircraft is seen to track east to west at the boundary with CTA-4.

Figure 1: Aircraft is seen to track east to west at the boundary with CTA-4.


The pilot reported that they had planned the route to fly for their solo qualifying cross-country flight as follows:

  • Wolverhampton/Halfpenny Green Aerodrome (EGBO) to Blithfield Reservoir – 22 NM
  • Blithfield Reservoir – Pitsford Water – 48NM 
  • Pitsford Water – Wellesbourne Mountford Aerodrome (EGBW) – 29NM

The route had been planned on a VFR 1:500,000 chart (figure 2) and a neat and comprehensive Pilot Log (PLOG) (figure 3) was produced using the methods taught on the navigation module of the PPL course. Prior to departure, the student pilot and their instructor reviewed the plan and weather conditions. The reported conditions on that day seemed to be reasonable and the flight was authorised. They discussed using the Birmingham Frequency Monitoring Code of 0010 to allow for easier identification when flying close to Birmingham’s controlled airspace. 

Figure 2: Route planned on a VFR 1:500,000 chart.

Figure 2: Route planned on a VFR 1:500,000 chart.

Although the PLOG has space for Regional QNH the pilot was aware of the risks of operating close to controlled airspace if a Regional Pressure Setting (RPS) is used and elected to use the Birmingham QNH.

Figure 3: Comprehensive Pilot Log (PLOG)

Figure 3: Comprehensive Pilot Log (PLOG)

Although the pilot had flown many navigation exercises and had done two solo navigation flights prior to the subject flight, they had only flown this particular route with their instructor on one occasion, three weeks earlier. 

After departure, the pilot noted that the visibility was good, but the wind was much stronger than expected. This resulted in some challenges to maintain headings and the vertical instability of the air meant it was difficult maintaining altitude. Therefore, a large portion of their time was spent on maintaining the heading and altitude leading to a significant increase in workload in flying the aircraft. It also resulted in their calculated timings not being as accurate. The pilot had had changed frequency to monitor Birmingham Approach on 123.980 MHz and displayed the FMC of 0010. They had not spoken to them as they had been busy trying to maintain their heading and altitude as well as navigate.

During the leg between Blithfield Reservoir and Pitsford Water, the pilot became uncertain of their location and had circled above Nuneaton VRP several times to establish a positive location fix. Unfortunately, they had not reset the timer in the aircraft before setting off from this point. Continuing on with the route, they flew over a body of water (Stanford Reservoir) which they mistook for Pitsford Water. As the student neared what they thought was Pitsford Water, the pilot selected an SSR code of 7000 and called Sywell Information on 122.705 MHz to inform them of what they thought was their location. Shortly after leaving the turning point that had been mistaken for Pitsford Water, the pilot changed frequency back to Birmingham Approach and selected the FMC of 0010. Given that their timings were already out, compounded by their lack of familiarity with that area of the country, they did not realise that the lake/reservoir was roughly 10 nautical miles before Pitsford Water. Therefore, when the pilot turned onto the heading for Wellesbourne Mountford it was made too early and had put them on track towards controlled airspace (figure 4). Unfortunately, at that time, there were several other aircraft that were contacting the controller; therefore the pilot could not call them. 

Figure 4: Planned and flown routes.

Figure 4: Planned and flown routes.

Realising, that they were flying in an area that did not correlate with the route plan and being unable to contact Birmingham, the pilot changed their  heading to south and called Distress and Diversion (D&D) on 121.500MHz. They promptly provided the pilot with a position fix and, once aware of their location, the pilot was able to navigate to Wellesbourne Mountford. On landing at Wellesbourne Mountford, once parked, the pilot immediately telephoned their instructor at Halfpenny Green and explained the problems that they had experienced en-route.

Findings and causal factors

The pilot had carried out good planning which was endorsed by their Flight instructor; the plan incorporated prominent turning points and waypoints en-route.  The weather was fit for solo VFR flight by a student although some unstable air resulted in increased cockpit workload associated with aircraft handling.  The route was to be flown 1,000 feet above MSA which provided ample vertical separation from controlled airspace; in accordance with the Take 2 guidance (remaining 2NM laterally clear and/or 200 feet vertically clear of controlled airspace) the planned route demonstrated text-book Threat and Error Management in this aspect.   

The pilot has also decided to incorporate the use of a Frequency Monitoring Code (FMC) into their plan due to the proximity of the route to the Birmingham controlled airspace complex. On leaving the Birmingham frequency south of Nuneaton, they selected 7000 after selecting the Sywell Information frequency prior to transmitting.  Once west of their turning point they again selected the Birmingham frequency followed by the FMC in accordance with good practice.  The pilot was, however, not fully aware that when using an FMC, no transmissions are required with ATC unless responding to a call.

The student pilot was not flying with a Moving Map as their use had neither been taught in their training nor had they been encouraged to use one. The CAA actively encourage all pilots to incorporate the use of Moving Maps in both pre-flight planning and in-flight.  TrainingCom (Spring 2020) states that it is important that instructors teach their students the use of GPS/GNSS aircraft systems when fitted to their aeroplane. The use of Moving Map displays should also be taught to enhance the student’s situational awareness once they have the basic Dead Reckoning (DR) navigation techniques. If the student uses these systems during solo-flying, this is permissible but they need to remember that they need to have the skills to later pass the licensing skills test. Therefore, it is the skills test that will be the time when the students DR Navigation techniques will be tested. Not only would a VFR Moving  Map have provided the pilot with this enhanced situational awareness as they approached what they incorrectly thought was their turning  point at Pitsford Water, but with a  properly configured display, a visual and aural airspace warning would have been given alerting the pilot of their proximity to controlled airspace.

In the pilot’s mind they expected to see a body of water after Lutterworth, the second waypoint on the second leg.  The pilot was on the correct ground track but due to a failure to incorporate the time taken to orbit at Nuneaton to establish their position, they became subject to confirmation bias. The sight of a body of water ahead on the route meant that the pilot’s expectations were confirmed, and the sensitivity of the error detection mechanism was reduced at a time when mental capacity was also taken up having just been unsure of their position and given the challenging air conditions.  Despite Stanford Reservoir being less than a third of the size of Pitsford Water, the pilot was probably so relieved to see a lake, as planned, that they failed to compute that they had not yet reached their turning point.  This chain of events could not have been broken when their position was passed to Sywell Information due to the lack of surveillance information available to the FISO.    

The pilot first became uncertain of their position when the expected ground features from Pitsford Water to Wellesbourne Mountford were not visible (figure 5). By now back on the Birmingham frequency and squawking 0010, the pilot was unable to seek assistance from the radar controller.  In need of assistance, the pilot immediately called D&D on 121.500MHz.  Very few pilots revert to their training and may have continued on track in the hope of finding a recognisable feature whilst compounding the risks associate with an airspace infringement.  On this occasion, the calm and logical execution of the Management technique of an identified Threat/Error enabled the pilot to establish a prompt resolution to the situation.

Any pilot who believes they are lost or temporarily uncertain of position should immediately seek navigational assistance from the appropriate radar unit. Alternatively, they should select code 0030 (FIR Lost) and contact D&D (callsign “London Centre”) on 121.500 MHz for assistance.

Figure 5

Figure 5

Post-flight analysis

Effective planning will always put you, as a pilot, in a position of strength for effective execution. But due to Human Factors, Threats and Errors will always exist and have the potential emerge.

In this occurrence, the pilot is to be commended for their handling of a stressful situation where an infringement was resolved in a timely manner.  In addition, despite limited experience in the aviation community, they carried out a detailed post-flight analysis (including the submission of a detailed and honest report) and adopted a Just Culture throughout. 

Focus on

Other narratives in this series can be found on the Infringement occurrences page.

06. Class D: Birmingham Control Area

Infringement of Class D – Birmingham Control Area

Date 22 November 2020
Aircraft Category Helicopter
Type of Flight Recreational Flight
Airspace / Class Birmingham CTA / Class D

Air traffic control

The Air Traffic Controller reported seeing an aircraft squawking 7000 enter the Class D CTA-2 near Warwick at 2,000 feet (Figure 1). It appeared to be following the M40 northbound. The aircraft descended to 1,800 feet then made a right turn and tracked eastbound climbing to 2,300 feet. The aircraft eventually turned southeast and left the CTA south of Coventry aerodrome. Multiple attempts to contact the aircraft were made on the frequency with no response.

Map showing where the aircraft entered the Class D CTA-2 near Warwick at 2,000 feet.

Figure 1: The aircraft entered the Class D CTA-2 near Warwick at 2,000 feet.


The pilot reported that they had planned a route to fly for their first solo flight as a PPL holder: Leicester Aerodrome – Deenethorpe Aerodrome – Podington racetrack – Olney VRP – Silverstone Circuit – Chipping Warden – Draycote Water VRP – Peter Hall Farm – Nuneaton VRP – Bruntingthorpe Aerodrome – Leicester Aerodrome.

The route had been planned on a VFR moving map on a tablet and transposed on a 1:250,000 VFR chart (figure 2). This was the first time they had used their personal iPad and the GPS stopped working 10 minutes after take-off.

As they had a well-prepared VFR chart, they continued with the flight having never had to rely on GPS previously when flying solo even though they had not flown the southern part of this route south of Northampton before.

After turning at Silverstone they had not noted the time and commented that they must have overshot Chipping Warden but, on seeing motorway, tracked it northwest bound until they could see Draycote Water VRP. By this time, they were beyond the area that was visible on the chart due to the way it was folded. As a result, they did not see the Class D CTA-2 with a base of 1,500 feet. Had they done so, they would have turned 180 degrees and tracked back down the motorway to avoid it.

The pilot added that they did not elect to obtain an air traffic service as they had to use the aircraft registration as their callsign instead of the instructors callsign used during training. In addition, as they routed northbound, they did not utilise the Birmingham Frequency Monitoring Code (FMC) of 0010 and listen out on 123.980MHz as they had not been taught about FMC during their training. At the time of the flight, the pilot reported there to be scattered cloud (3-4 oktas) at about 2,300 feet with good visibility below.

The planned route shown on 1:250:000 VFR chart

Figure 2: The planned route shown on 1:250:000 VFR chart.

Causal factors

The pilot had carried out good planning to carry out their first solo flight after the award of their licence. They had selected prominent geographical features as turning points and in accordance with good practice had planned to use a tablet-based VFR moving map with the paper chart as a back-up.

Shortly after departure, their GPS position failed as they were unaware that the tablet needed to be tethered to their phone as the tablet was not a cellular version.

The pilot lost situational awareness as to their position sometime after their waypoint at Silverstone Race Circuit (figure 3).  Having been unable to locate the next waypoint at Chipping Warden, decided to follow the M40 motorway northbound. Due to the lack of aeronautical information available to the pilot, they entered the Birmingham CTA-2 to the southwest of Warwick at 2,000 feet where the base of controlled airspace is 1,500 feet.

Map showing waypoints

Figure 3: Situational awareness as to their position was lost sometime after the waypoint at Silverstone Race Circuit.

In their pre-flight planning, the pilot applied good Threat and Error Management in marking the route on a paper chart. However, the manner in which the chart had been folded did not leave sufficient airspace and ground features visible to aid navigation. It is essential, as part of pre-flight preparation that you are not only familiar with the equipment functionality and limitations that you intend to rely on in-flight but that contingency measures are suitably prepared.

As the pilot routed northbound from Chipping Warden, as part of the initial plan, good practice would have been to employ the use of a Frequency Monitoring Code (FMC) by selecting the Birmingham frequency of 123.980MHz and then selecting a squawk of 0010 Mode C as their intended route would have taken them close to the Birmingham CTA and well within the notified FMC area of recommended use (see UK AIP EGBG AD2.22 Flight procedures paragraph 7 and the chart at UK AIP ENR 6.80).  The FMC is also annotated on the chart (figure 4). However, it was not incorporated into their plan as, at the time of the occurrence, the pilot was unaware of FMC and their use. Had they been aware, the infringement would have been resolved in a timely manner and navigation assistance offered at an early stage of the occurrence.

FMC annotated on the chart.

Figure 4: FMC annotated on the chart.

The pilot first became uncertain of their position when they missed their turning point at Chipping Warden having not noted their time at Silverstone. However, being unable to locate the aerodrome should have been a trigger to seek assistance from an Air Traffic Service Unit.  A number of options were available including calling D&D on 121.500MHz for either a position fix or a steer to Draycote Water or calling Birmingham on 123.980 MHz for assistance or the LARS unit at Brize Norton on 124.275MHz (offering a service radius of 40NM daily between 0800 hours UTC and 1600 hours UTC).

However, due to the lack of experience of the pilot and then having only ever used an instructor callsign throughout their training rather than their aircraft registration. A lack of confidence in the use of the radio impaired their decision making. It is important for pilots to understand that air traffic control is there to help them and that controllers are used to offering navigational assistance when required.

A chart showing areas of responsibility for the UK LARS units can be found in the UK AIP at ENR6.11. Further details on units participating in the Lower Airspace Radar Services can be found in the UK AIP at ENR 1.6.4 (figure 5).

Lower Airspace Radar Services can be found in the UK AIP at ENR 1.6.4

Figure 5: Lower Airspace Radar Services can be found in the UK AIP at ENR 1.6.4.

Post-flight analysis

This unfortunate occurrence occurred so soon after the pilot had completed their training due to gaps in knowledge, a lack of confidence in operating their radio in flight and lapses in Threat and Error Management.

The pilot is commended for carrying out such detailed post-flight analysis of the occurrence (including the submission of a detailed and honest report), their approach to the factors surrounding the occurrence and for following Just Culture principles.

Focus on

Other narratives in this series can be found on the Infringement occurrences page.

05. Class D: Manchester Control Area

Infringement of Class D – Manchester Control Area

Date 9 December 2020
Aircraft Category Fixed-wing Microlight
Type of Flight Recreational Flight
Airspace / Class Manchester CTA / Class D

Air traffic control

The Manchester radar controller was alerted to an aircraft squawking 7365 a few miles to the northeast of Barton aerodrome. The aircraft was indicating an altitude of 2,400 feet (1). The base of the Manchester CTA is 2,000 feet.

Mode S allowed the aircraft to be identified so the controller was able to contact the Barton Flight Information Service Officer (FISO). After a second call to Barton the aircraft descended.

The aircraft was inside controlled airspace for 3 minutes and 36 seconds before leaving the CTA. No other traffic was affected by the infringement.

The Barton FISO explained that the unit is part of an ADS-B (Automatic Dependent Surveillance–Broadcast) trial. This allows a FISO to offer generic traffic information (TI) to pilots operating within the unit’s designated operational coverage (DOC). Manchester Barton’s DOC is notified as 10NM/3,000 feet. Generic traffic information is given using phrases such as “in your vicinity”.  The FISO could see that the frequency had not been changed to Warton after the aircraft left the unit’s DOC heading north. So issued TI on traffic that was approaching position from the east (see figure 1).

Map showing the position of the aircraft and the approaching traffic

Figure 1: The position of the aircraft is shown as ‘1’ and the approaching traffic as ‘2’

On recovery to Barton, the pilot informed the FISO that they were over Bury (figure 2). The FISO issued TI against an aircraft that was departing the ATZ northbound in a reciprocal direction.

Map showing the position of the aircraft over Bury

Figure 2: Position of the aircraft over Bury

At that point the aircraft was inside the DOC area, and the FISO commented to their assistant that, based on ADS-B altitude, the aircraft appeared high compared with the reported altitude.

The FISO was about to ask the pilot to confirm their altitude and pass updated information on the opposite traffic when the Manchester radar controller called to let them know the traffic was too high. The pilot was informed and carried out a descent out of the CTA to the correct altitude for an overhead join.


The pilot was carrying out a VFR sightseeing flight from Barton to Rawtenstall via Bury and Ramsbottom (figure 3).

On the day of the flight, met conditions were good. Visibility was in excess of 10km with some cloud detected at around 4,000 feet and a light and variable surface wind.

Map showing route from Barton to Rawtenstall via Bury and Ramsbottom

Figure 3: Flight from Barton to Rawtenstall via Bury and Ramsbottom

The pilot usually flew with a fellow pilot to supplement each other’s navigation, lookout and communications. On this occasion they were flying solo as their flying partner was unavailable. The pilot was flying the EV97 for the first time in some months. The pilot was using a 1:250,000 VFR chart and a basic version of a VFR moving map application on their mobile phone. This was secured in a mount on the right-hand side of the instrument panel due to the location of the 12V socket and position of the mount. The pilot explained that mounting a moving map is limited to the right-hand side as nothing can be fixed to the canopy. This meant that altitude information was very difficult to see from the left-hand seat. The aircraft was not equipped with either strobes or a beacon and, due to its bare aluminium colour, the pilot was aware that it was harder to see air-to-air than white microlights. The pilot remained on the Barton frequency throughout the flight and was in receipt of a Basic Service from Barton Information.

On the outbound leg, the FISO issued a warning of a much faster aircraft heading in a reciprocal direction. The microlight pilot became extremely anxious that the pilot of the conflicting aircraft would not become visual and all their focus turned to lookout, scanning all around in an unsuccessful attempt to catch sight of the aircraft. Although trimmed for level flight, the microlight had started a gradual climb from Bury to reach an altitude of 2,700 feet at Rawtenstall. Due to their focus on scanning, the pilot had not realised that the aircraft had climbed approximately 1,000 feet above their intended cruising altitude. On turning back towards Barton, and not realising they had climbed so much, a quick glance at the altimeter told the pilot that the aircraft was at *,800 feet. Having intended to fly at around 1,700 feet, the pilot mistakenly took this reading to be 1,800 feet. It was really 2,800 feet. The pilot started a gradually descent of 300 feet to what they thought was 1,500 feet, but was actually 2,500ft. This altitude was maintained the rest of the way back to the Barton overhead.

The pilot made two position reports en-route at this altitude of “Overhead Bury, one thousand five hundred feet” and “Half a mile north of Swinton Interchange at one thousand five hundred feet”. Overhead Barton, the FISO asked the pilot to check their altitude at which point they realised that the needle on the altimeter was pointing towards “2” not “1”. The pilot apologised whilst commencing a steep descent into the Barton circuit. The pilot added that a smaller aircraft or one with less performance in their proximity, “as often happens around Barton”, would not have caused them so much concern. But the warning of a larger aircraft travelling at a much higher speed triggered a serious worry about the risk of a mid-air collision had affected their concentration.

Figure 4 shows an approximate representation of the flight profile.

Map showing an approximate representation of the flight profile.

Figure 4: Approximate representation of the flight profile.

After the event the pilot analysed the occurrence, and noted a number of factors that led to them not noticing the higher altitude:

  • Better conspicuity would lessen the stress of not being seen by other aircraft thereby reducing their focus on external scan and allowing some division of attention between lookout and instrumentation.
  • A check of the basic version of the VFR moving map technology led them to note that their version did not offer warnings of possible vertical infringements.
  • The mobile phone was positioned so far away from the pilot that they could not get an independent altitude check from that equipment.
  • In previously flown aircraft, they recall seeing an additional display within the altimeter showing the altitude in numbers.

Causal factors

The pilot had planned to carry out a sightseeing flight to the north of Barton. The decision to use a 1:250,000 chart, allowing greater definition of the route features, was good based on the aircraft’s speed and the relatively short distance of the flight (approximately 15NM from Barton aerodrome). The use of a chart for navigation was supported by a VFR moving map.

However, in becoming distracted in trying to visually acquire conflicting traffic, an inadvertent climb resulted in the aircraft eventually reaching 1,200 feet higher than the intended cruising altitude.

The pilot was subject to confirmation bias. They knew they wanted to fly at or around 1,500 feet and the small needle on the altimeter pointed to 800 feet. In the pilots mind they expected to be at or around 800 feet. Having not flown the EV97 solo for some time, they were not surprised to have reached a slightly higher altitude by a few hundred feet.

Nothing in their plan or the small needle on the altimeter was to indicate that they were over 1,000 feet higher than intended. The confirmation bias could have been broken by one, or both of the following:

  • The pilot normally flew with another pilot who has a tablet device with a ‘full’ version of a VFR moving map application. Had the pilot has such a device/version, even as a back-up to their using the 1:250,000 VFR chart, they would have had the benefit of a larger display which would have provided them with alerts as they climbed up to 2,800 feet with the Manchester TMA being above them at 3,500 feet. It would also have provided an alert on the inbound leg as they approached the Manchester CTA some 300 feet above the base altitude and then again as the CTA base stepped down to 2,000 feet.
    These warnings are shown when the trajectory, both horizontal and vertical, would take an aircraft into a volume of airspace. An onscreen warning is often accompanied by an audible alert, the form of which depends on the type of airspace, and a thick border may be drawn on the map accompanied by large coloured arrows to highlight which piece of airspace is associated with the warning.
    The CAA and safety partners actively encourage all pilots to incorporate the use of moving maps in both pre-flight planning and during flight. On this occasion, the pilot had not applied active Threat and Error Management in relation to their equipment in respect of the size and position of the display and the functionality of the ‘basic’ version of the application. In addition, the lack of options for the position of the mount may have played a part in accessing data from the moving map.
  • Had the pilot elected to obtain an air traffic service from the local LARS unit at Warton on 129.530MHz the chain of events may have been broken. On initial contact the pilot may have noticed the error when passing their details to the controller or, when they told Warton Radar that they were at 1,800 feet, Warton Radar would have noted an error in the Mode C when carrying out the verification and validation process during identification for a radar service. The Barton DOC is notified as 10NM/3,000 feet. When leaving the DOC area northbound, the pilot would have been better served getting a service from Warton.

The pilot became task saturated. While trying to visually acquire the aircraft for which they received information they failed to note an inadvertent altitude change. The pilot cannot be criticised for being risk aware and concerned of the developing situation. However, the use of an electronic conspicuity device on a larger display and/or the provision of an air traffic service are effective mitigations of mid-air collision. With mitigations in place capacity can be increased and stress levels reduced.

Having operated the EV97 for some time some skill fade may also have been a contributory factor.

Post-flight analysis

The pilot is commended for carrying out such detailed post-flight analysis of the occurrence (including the submission of a detailed and honest report), their approach to the factors surrounding the occurrence and for following Just Culture principles.

In addition they immediately engaged the services of a flight instructor to obtain remedial refresher training to ensure that issues could be addressed and rectified.

Focus on

(1) Please note that Mode A code and Mode C pressure-altitude have not been verified.

Other narratives in this series can be found on the Infringement occurrences page.

04. Class D and Class A: Gatwick Control Area and London Terminal Control Area

Infringement of Class D and Class A airspace – Gatwick Control Area and London Terminal Control Area

Date 6 August 2020
Aircraft Category Fixed-wing Microlight
Type of Flight Recreational Flight
Airspace/Class Gatwick CTA / Class D and
London Terminal Control Area (LTMA) / Class A

The Air Traffic Controller

The Air Traffic Controller reported receiving a Controlled Airspace Infringement Tool (CAIT) alert of an aircraft squawking 7000 indicating 1,800 feet briefly enter the Gatwick Control Area (CTA). Some 13 minutes later, the aircraft was seen to enter the LTMA in the vicinity of the Mayfield VOR/DME (MAY) at 2,900 feet. Whilst the controller was planning what action was required to ensure separation was maintained with an aircraft inbound to Gatwick Airport, the unknown aircraft descended below controlled airspace.

These infringements did not result in a Loss of Separation due to the significant reduction of commercial traffic at Gatwick associated with COVID-19. But under normal traffic conditions, due to the location of the infringements, this event may have caused a safety event and considerable workload for commercial pilots and controllers.

The Pilot

The pilot reported that the flight was planned to fly from Headcorn to Deanland and return to Headcorn later. The cloud base at the time was approximately 1,600 feet and the visibility was good. Despite the good visibility, the lower than expected cloud base did cause some distraction.

The aircraft was equipped with, and the pilot was operating, a MODE S transponder and squawking 7000 with MODE C. Whilst aware of the benefits of moving map technology, the pilot had chosen not to use one as they did not want to become over reliant on it to avoid degradation of conventional navigation skills.

The pilot had planned the flight, and was using a 1:250, 000 VFR chart, although no route line was drawn on the chart. Flying a heading of 240 degrees the pilot misidentified Bewl Water as Darwell Reservoir resulting in them being north of their intended track. This led to being too far to the west when trying to visually locate Deanland, the destination aerodrome. Having failed to locate Deanland, the pilot decided to return to Headcorn and turned left onto a reciprocal track when approximately 3NM southeast of Haywards Heath. When the cloud base improved, a climb was initiated but as they were further west than they thought, the pilot infringed the LTMA as they were still under the area where the base is 2,500 feet.


The TAF at the time of the Infringement forecast an improving cloud base after 0700 hours UTC:

EGKK 060458Z 0606/0712 20007KT 9999 BKN010
TEMPO 0606/0607 BKN007
PROB30 TEMPO 0606/0607 6000 -RADZ BKN004
BECMG 0607/0610 SCT030
PROB30 0702/0707 8000=

The METARS as issued:

0750 EGKK 060750Z 19007KT 160V230 9999 BKN013 20/17 Q1007=
0820 EGKK 060820Z 21006KT 160V240 9999 BKN012 20/17 Q1018=
0850 EGKK 060850Z 22007KT 190V250 9999 BKN015 21/17 Q1018=

Causal Factors

The pilot had planned to carry out a direct flight to Deanland.  Based on the aircraft’s speed and the relatively short distance of the flight the decision to fly using 1:250,000 chart was sound and greater definition of route features were available.  However, in selecting an initial incorrect heading, the outbound track was offset to the north of the water feature of Bewl Water (A in Figure 1).  The pilot knew that they wanted to be north of Darwell Reservoir (B in Figure 1) and once airborne from Headcorn and visual with a large water feature, the pilot became subject to confirmation bias.

In the pilots mind they expected to see a water feature to the south. Because the pilot was familiar with the area and had flown the route many times, they knew that they needed to be just to the north of Darwell Reservoir. The sight of a body of water to the left of the route meant that the pilot’s expectations were confirmed, and the sensitivity of the error detection mechanism was reduced at a time when mental capacity was also taken up with the distraction of lower-than-expected cloud. By keeping Bewl Water to their left the pilot was destined to infringe the Gatwick CTA.

Figure 1 Bewl Water and Danwell Reservoir

Figure 1 Bewl Water and Darwell Reservoir

The pilot’s planning was complacent due to the number of times the route had been flown and their knowledge of the area:

  • No attempt was made to obtain the upper winds by using the MetForm 214 or other APPS.
  • A line was not drawn on a chart between Headcorn and Deanland.
  • A Navigational Plan/ Log (PLOG) was not constructed for the flight.

As a result of the 2,000 feet wind on the day (approximately 180 degrees /10 knots), the heading flown gave a ground track (red line in figure 2) of approximately 250 degrees.  The heading required to fly a direct track from Lashenden to Deanland was approximately 224 degrees (purple line in figure 2). With a lowering cloud base en route, the pilot became distracted from the navigation task and the effects of the initial heading error were not challenged.

Figure 2 Ground and direct tracks

Figure 2 Ground and direct tracks

The pilot’s normal method of navigation was to use dead reckoning techniques. Had the pilot used a moving map, even just as a back-up, they would have quickly identified that the aircraft was significantly off track and that Bewl Water was not Darwell Reservoir.  In addition, as the pilot approached the Gatwick CTA, with correct configuration, a visual and aural warning could have been provided. These warnings are triggered when the horizontal and vertical trajectory would take an aircraft into a volume of controlled airspace. An onscreen warning is often accompanied by an audible alert, the form of which depends on the type of airspace, and a thick border may be drawn on the map accompanied by large coloured arrows to highlight which piece of airspace is associated with the warning. The CAA and safety partners actively encourage all pilots to incorporate the use of moving maps in both pre-flight planning and during flight.

At no time did the pilot believe they were lost. They became uncertain of their location when they were unable to locate Deanland which the pilot commented is not an easy aerodrome to locate due to the surrounding landscape. However, being unable to locate the aerodrome should have been a trigger to seek assistance from an Air Traffic Service Unit.  A number of options were available including calling D&D on 121.500MHz for either a position fix or a steer to Deanland; calling Gatwick on 126.825MHz or Farnborough LARS (East) on 123.225MHz.

A chart showing areas of responsibility for the UK LARS units can be found in the UK AIP at ENR6.11. In the case of Farnborough LARS, there are annotations on the VFR Charts (see figure 3). A last barrier could have been the use of the Frequency Monitoring Code (FMC) for Gatwick.  Although the intended track of the flight would have been 2NM to the south of the published area for the Gatwick FMC (7012 and 126.825MHz), the first, brief, infringement, would have been acted upon by the Gatwick Director which may have acted as a trigger to the pilot that they were some 8.5NM north of track.

Figure 3 Farnborough LARS East

Figure 3 Farnborough LARS East

Focus on

Other narratives in this series can be found on the Infringement occurrences page

03. Class A: Cotswold Control Area

Infringement of Class A airspace – Cotswold Control Area

Date 20 August 2020
Aircraft Category Fixed-wing Microlight
Type of Flight Instructional Flight
Airspace/Class Cotswold CTA / Class A

Met information

At the time of the infringement the local QNH both at Brize Norton and Fairford was 1003 hPa. The cloud was BKN (5-7 oktas) at 4,800 feet and the forecast 5,000 feet wind on the UK Low-level Spot Wind Chart (Form 214) was 190/30.

The Air Traffic Controller

The Air Traffic Controller reported observing an unknown aircraft squawking 7000 indicating FL071 (7,100 feet based on 1013 hPa) enter the lateral confines of L9 in the vicinity of the IFR reporting point GAVGO, which is near Swindon. The aircraft remained in L9 for a period of 9 minutes 32 seconds. The aircraft was later observed to change to a Brize Norton conspicuity squawk (3737) but the Brize Norton Air Traffic Service Unit was unable to establish contact with the pilot.

The Pilot

The pilot reported that the training flight was being conducted in very local and familiar airspace. Navigation was being carried out using a 1:250K VFR chart with no GPS/Moving Map. The initial part of the flight was conducted under a layer of cloud (reported to be at 4000-5000 feet) but training was made difficult due to turbulence. The aircraft was turned south to remain clear of the Cotswold CTA with a base of FL065 and climbed above the cloud. Due to strong winds aloft, the aircraft was not positioned as far south an anticipated and with repeated turns the aircraft was ‘blown back’ into L9. The pilot found it difficult to determining their position due to only intermittent sight of the surface as a result of operating above cloud; they felt that the infringement was increased due to the low QNH.

Causal Factors/Findings

1:250,000 VFR charts have a vertical limit of airspace of 5000 feet ALT. The decision to climb to an altitude where no airspace information was available in the cockpit was the result of the instructor being  inadequately prepared for this flight. Figure 1 compares the information available on the 1,250,000 with the 1:500,000 chart. Figure 2 shows the warning annotated on all 1:250, 000 charts to remind users of the vertical limits.

1,250,000 vs 1:500,000 chart

Figure 1: 1,250,000 vs 1:500,000 chart

1:250, 000 chart warning to remind users of the vertical limits

Figure 2: 1:250, 000 chart warning to remind users of the vertical limits

The infringement lasted 9 minutes 32 seconds. Figure 3A shows the area on a 1:500,000 chart. Figure 3B shows the same area on the chart available to the instructor in the cockpit.

Area shown on a 1:500,000 chart

Figure 3A: Area shown on a 1:500,000 chart

Area on the chart available to the instructor

Figure 3B: Area on the chart available to the instructor

When it became clear that prevailing weather conditions required a change to the plan after departure the instructor should have either abandoned the flight or revised their plan. To mitigate against risks associated with over confidence/complacency their revised plan needed decisions based on aeronautical information available in flight, rather than perceived knowledge.

The instructor chose to operate without a Moving Map. The CAA and safety partners actively encourage all pilots to incorporate the use of Moving Maps in both pre-flight planning and in-flight.  When properly configured and used effectively, a visual and aural airspace warning would have been given alerting the pilot of their proximity to controlled airspace.

The instructor failed to recognise the Threats associated with cloud base and strong winds aloft. This resulted in the pilot losing situational awareness of the aircraft’s position. Once above cloud and unable to maintain positional awareness, the pilot made an Error in not requesting an air traffic service (ATS) from the local Lower Airspace Radar Service unit; Brize Norton is just 12NM from the location of the infringement.

At 1003 hPa, the QNH was not uncharacteristically low but it meant that the aircraft was some 300 feet higher on the local QNH when adjusted for the Standard Altimeter Setting (the correct pressure datum of the Cotswold CTA). However, the aircraft was still flown some 600 feet higher than the base of controlled airspace. Had the Instructor had the correct chart available and having stated they were aware of the Class A airspace with a base of FL065, they should have incorporated a maximum altitude of 6,000 feet on the QNH of 1003 hPa into their plan to remain below controlled airspace. This, in line with Take 2 guidance, would have ensured they were operating below the CTA and have a buffer of 200 feet to allow the management of the Threats associated with turbulence or student handling error.

When the pilot eventually displayed a Brize Norton SSR code the unit was unable to establish 2-way communications. In the first instance a pilot should only select the conspicuity code (3737) when instructed to do so or in accordance with local procedures.  Had the pilot intended to display the Frequency Monitoring Code (Listening squawk) the code selected should have been 3727 with the relevant frequency selected (124.275 MHz).

Instructors often lower the volume of the comms panel/radio during instructional flights as constant R/T can distract the student and impede in-cockpit talk between instructor and student.   It is not uncommon in occurrence involving instructional flights for ATC not to be able to establish communication with the pilot for this reason.

Focus on

02. Class D: Stansted Control Area 4 and Luton Control Area 1

Infringement of Class D airspace – Stansted Control Area 4 and Luton Control Area 1

Date 26 September 2020
Aircraft Category Fixed-wing Aeroplane
Type of Flight Recreational Flight
Airspace/Class Stansted & Luton CTA / Class D

The Air Traffic Controller

The Air Traffic Controller reported that they had traffic on a right-base for Runway 25 at London Luton Airport descending to 3,000 feet. A radar contact was seen to climb into controlled airspace south of Royston passing 2,600 feet before stopping the climb at 3,000 feet on an approximate track of 250o. Traffic information was passed to the Luton arrival aircraft and it was turned onto a shorter final to avoid the infringing aircraft. At this point the unknown aircraft selected 0013 squawk and the controller was able to ascertain their callsign and get 2-way communication with him. The pilot informed the controller they were leaving controlled airspace to the north which they subsequently did. The aircraft was then identified and given a service as per the pilot’s request. The Luton arrival was then re-vectored and completed a safe approach to land.

The Pilot

The pilot reported carrying out a recreational flight from Duxford to Cornwall via Wing (west southwest of Leighton Buzzard) to route to the north of the Luton Control Zone. The route was planned to be flown at 3,000 feet to remain below the CTAs with a lowest base of 3,500 feet. The plan was to climb straight ahead to 3,000 feet on a heading of 251o after departure from Runway 24 (Figure 1).

Figure 1

Figure 1

On the morning of the flight there was a strong northerly wind flow down the east side of the UK. The associated TAF were as follows:

  • Stansted: 300/14, PROB 40 TEMPO 2606/2609 32018G28
  • Luton: 300/14, TEMPO 2606/2706 33018G28.
  • The forecast 2,000 feet wind at 5230N 00E was 340/35 (35 knots at 90o to the planned track)

Just before departure an aircraft called Duxford Information to state they would be conducting visual circuits at Fowlmere (2.5NM west southwest of Duxford). On lining up for departure the pilot was informed of the traffic at Fowlmere and the surface wind “being something like 310/16”.

On climb out the pilot encountered the most vigorous turbulence that they could recall flying in for many years. They elected to hold runway heading as best they could to climb straight ahead out of the ATZ without turning right to the track of 251o degrees to enable them to remain clear of Fowlmere (blue line in Figure 2); the passenger was asked to look out for the Fowlmere circuit traffic. Given the turbulence, the pilot elected to climb at best rate of climb speed, which was approximately 80 knots, with the aim of getting into smoother air as soon as possible.

Once clear of Fowlmere, the pilot called Duxford to leave their frequency, changed to Luton Radar on 129.550 MHz and then selected the Luton Frequency Monitoring Code (FMC) of 0013. With the long nose of the aircraft, forward visibility is limited when climbing steeply; unfortunately, that meant fewer visual cues as to actual track were available to the pilot. As the aircraft approached 3,000 feet the pilot asked the passenger to pass them their Moving Map tablet that had been running since departure. The pilot was just noting they had had flown to the left of the airspace line (magenta line in Figure 2) when Luton Radar called to advise that they were indicating at 2,800 feet and was advised immediate descent to below 2,500 feet. Realising their error, the pilot responded that they were descending and turning north to head out of the Stansted CTA as quickly as possible.

Figure 2

Figure 2

ATC aspect

The airspace and track where the aircraft infringed is routinely used by Luton and Stansted traffic. This incident took place when the traffic was light and therefore the consequences of the infringement was minimal. Following agreement with the pilot of the arriving aircraft the controller re-positioned the aircraft and ensured minimum separation was achieved between the two aircraft However, in normal traffic levels with a continuous stream of arrivals the ability to reposition the aircraft without any impact on subsequent arrivals is unlikely. The workload increase for pilot and controller is significant under these circumstances with safety remaining paramount. One infringement of only a few minutes can result in many minutes of delay to operators, with additional fuel burn and emission also a consideration.

Causal Factors/Findings

The pilot carried out detailed and effective planning in route selection to remain outside controlled airspace and included the use of FMC along the route. In addition, they were equipped with a Moving Map which was intended to be used actively en-route. They also recognised the Threat associated with dual operations at Duxford/Fowlmere.

However, a minor change to the plan moments prior to departure allowed the introduction of lapses in wider Threat and Error Management. The decision to fly further south in strong cross winds and to climb at a higher rate resulted in the aircraft’s track being affected greater over a shorter distance the aircraft drifting further south of track than had been anticipated. The pilot, unaware of their ground track due to reduced forward visibility associated with the aircraft’s attitude then lost situational awareness and extended beyond that required to avoid the traffic flying circuits to the north of Fowlmere. By the time the aircraft was south abeam the Runway 25 threshold at Fowlmere, it was 1.2NM south and passing 1,500 feet. In addition, had the pilot identified that routing to the south of Fowlmere would take them closer to the Class D CTAs they may have identified the increased value to using the Moving Map. This would have enabled them to regain situational awareness lost through the aircraft’s attitude. The pilot could have either turned right back onto track or stop their climb below 2,500 feet to remain below the CTA. However, the pilot was faced with several distracting factors from their original plan and their capacity was rapidly being used in handling the aircraft in extremely turbulent conditions whilst considering the traffic at Fowlmere and the wellbeing of their passenger.

In their wider plan, the pilot had considered the Take 2 aspect to remain clear of controlled airspace but that was not revised following the amended plan to deviate to the south of Fowlmere and thereby fly close to the CTA. Had the pilot only climbed to, for example 2,300 feet, until closer to Royston, the infringement could also have been avoided. This probably did not enter the pilots thought process as the focus was on climbing out of the turbulence, avoiding the Fowlmere visual circuit, and selecting the next radio frequency and FMC.

Notwithstanding the lapses in Threat and Error Management, the pilot’s initial plan was good and incorporated several key measures to prevent airspace Infringements:

  1. Comprehensive planning including airspace avoidance and meteorology;
  2. Use of a Moving Map; and
  3. Use of an FMC.

That decision to use an FMC enabled early intervention by air traffic control to assist the pilot and resolve the situation promptly. In addition, detailed post-occurrence analysis and open and detailed reporting by the pilot enabled lessons to be identified to avoid a recurrence.

Focus on

01. Class D: Birmingham Control Area 1

Infringement of Class D airspace – Birmingham Control Area 1

Date 24 August 2020
Aircraft Category Fixed-wing Aeroplane
Type of Flight Recreational Flight
Airspace/Class Birmingham CTA-1 / Class D

The Air Traffic Controller

The Air Traffic Controller reported that Runway 33 was in use at Birmingham with one aircraft shortly to depart. The controller was alerted to an unknown aircraft entering CTA-1 indicating 1,900 feet and squawking 0010 (the Birmingham Frequency Monitoring Code). Using MODE S derived information, the controller made a transmission to the pilot and asked them to descend immediately. The departing aircraft was instructed to depart straight ahead to maintain separation to the west of the infringing aircraft. The pilot stated they were mistakenly inside the CTA and descended; the aircraft was identified, issued with a discrete squawk and, once clear of the CTA, offered a Basic Service. Sometime later the aircraft climbed again into the CTA to 1,600 feet and, when informed of the climb, the pilot carried out an immediate descent.

The Pilot

The pilot was prompt to submit a comprehensive report to the CAA. They reported that the aircraft had recently had a complete avionics refit with all original radios and navigation equipment replaced with fully integrated GPS/NAV/COM/MFD equipment, Electronic Flight Instruments and an autopilot. Initial flights post-installation were carried out for the pilot to become familiar with the basic instrumentation; the subject flight was planned for a longer distance to test the autopilot. The pilot openly admitted that the new avionics were not the reason for the infringement but “sloppy planning” carried out on the morning of the flight was a contributory factor. In that planning session, the pilot had ‘rubber banded’ the magenta line on the Moving Map. The red line in Figure 1 shows the route planned and that flown. Having taken the northern route around Birmingham many times, after departure the pilot usually routed at 1,900 feet to Lichfield Disused, then west between Cosford and Wolverhampton Aerodrome Traffic Zones taking them below the Birmingham CTA-3 with a base of 3,500 feet (blue line in Figure 1).

On the day of the infringement, the pilot followed their plan that took them west through, and not below, the similarly shaped but lower CTA-1 which has a base of 1,500 feet. On hearing their callsign broadcast by the Birmingham air traffic controller, the pilot’s first instinct was to disengage the autopilot and follow the requests of the controller. They then accepted a basic service and a discrete squawk. The second climb was thought to have occurred as the pilot wouldn’t normally fly as low as 1,500 feet over the built up areas to the west of Aldridge towards Walsall; they reported that they were most likely conscious of a lack of clearance with the terrain which, in that area, lies between 450 feet and 500 feet amsl. The rest of this flight, and the return flight home was uneventful.

The pilot added that on any other day they were sure they would have noticed the mistake of their plan in the air because the route was clearly wrong. However, distraction caused by focussing on the new avionics drawing more of their attention led them to miss the planning error.

After the occurrence, the pilot elected to take time with an instructor who was familiar with the new avionics to carry out some more familiarisation training and navigation practise.

Airspace Infringement of Class D Airspace - Birmingham Control Area 1 : Figure 1

Figure 1

Causal Factors/Findings

The pilot is to be commended by their openness and post-occurrence actions. This occurrence demonstrated the benefit of using a Frequency Monitoring Code (FMC); the pilot reported that they use them whenever they are available in the areas in which they are flying. This positive approach to, and correct use of, the FMC allowed the initial infringement to be resolved promptly by the controller and pilot. In addition, the pilot correctly operated their transponder with MODE C (ALT) alerting the controller to the infringement; had MODE C not been operated, the controller would have been correct to have ‘deemed’ the aircraft to be below the CTA. Had that been the case, the risk of a mid-air collision or the infringing aircraft being affected by wake turbulence would have been heightened.

Poor planning and a failure to double check the route and associate altitudes of the airspace resulted in confirmation bias that they were able to fly at 1,900 feet. In the planning phase, by creating a back-up on a paper chart, you are often notice additional information/details that you don’t always notice on your Moving Map display.

Even though the pilot was flying with a Moving Map, it is not known why there was no response to the alert. It is possible that the confirmation bias led the pilot to dismiss the alert without noting its subject. When properly configured and used, an airspace warning would have been given the pilot a timely alert of their proximity to controlled airspace.

In summary, the pilot did not carry out sufficiently detailed pre-flight planning which, combined with confirmation bias and distraction from overly focussing on new avionics, resulted in their flying into Class D controlled airspace without an air traffic control clearance. However, textbook use of an FMC allowed the infringement to be resolved in a prompt manner.

Despite some errors associated with Human Factors, the pilot has embraced a Just Culture and identified the benefits associated with completing the appropriate refresher training which was carried out with a Flight Instructor.

Focus on

Controller’s stories

A series of controller’s stories from NATS

Mark Davenport, an air traffic controller at Swanwick centre, talks about his experience with airspace infringements. Airspace Infringement Series: A controller’s story… (20 May 2019)

Brian Ringrose is an air traffic controller at Swanwick centre. He talks about his experience looking after airspace around Gatwick. Airspace infringement series: A controller’s story (12 April 2019)

Amanda Rhodes is an air traffic controller at Swanwick Centre.  She talks about her experience looking after airspace around Luton Airport. Airspace Infringement Series: A controller’s story (22 March 2019)

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