Textbook application of a listening squawk allows early resolution of an infringement in a busy volume of airspace
As a measure to reduce the number and impact of airspace infringements, the CAA has introduced a series of Secondary Surveillance Radar (SSR) codes. There are 25 Frequency Monitoring Codes (FMCs) which are also known as listening squawks.
Listening squawks allow an Air Traffic Service Unit (ATSU) to be aware of aircraft that are on their frequency and enables the ATSU to quickly contact the pilot. In turn Air Traffic Control (ATC) can rapidly resolve infringements before they can become potentially more serious incidents. When controller capacity has allowed the pilot of an aircraft can be warned if it appears that it might infringe Controlled Airspace. Since their introduction many airspace infringements have been prevented by these warnings. On even more occasions, ATC has been able to rapidly resolve infringements before they became more serious. One such occurrence took place on 18 August 2019.
The pilot involved in the infringement plans all flights thoroughly, uses a moving map and has demonstrated an excellent approach to airmanship. The pilot reported having planned a local flight that had been flown many times and the plan incorporated the use of a moving map and Frequency Monitoring Codes (FMC).
The purpose of the flight was to fly a friend who had not flown in the aircraft type before. The passenger was excited about the flight and was asking lots of questions. Despite using a checklist, the pilot became distracted by the passenger and forget to set the correct QNH from that used during a previous flight. In addition, the pilot also failed to check the volume control on the iPad. After departure the pilot changed frequency to Farnborough LARS and set the FMC on his transponder. It was not until the Farnborough LARS controller transmitted his callsign, that he checked his iPad and, seeing a bright RED border, realised that he was too high in his current position and was infringing the Gatwick Control Area. On hearing his callsign the pilot immediately descended rapidly whilst apologising to the controller.
The LARS controller reports seeing and hearing the Airspace Infringement Alarm showing a 4572 (Farnborough LARS West FMC) infringing the Gatwick CTA with a MODE C indicating 1700 feet.
The controller called the aircraft using its callsign as seen on MODE S. The pilot answered straight away and said that he was following his moving map and remaining outside the Gatwick Control Zone. The pilot was asked to confirm his altitude on the London QNH of 1006 hPa. The pilot replied saying he was at 1600 feet on that QNH. The pilot was reminded that the base of controlled airspace in that location was 1500 feet and was asked to descend to 1400 feet to leave controlled airspace. The pilot replied that he was descending.
The pilot descended out of controlled airspace, apologised for the infringement and thanked the controller for assistance given.
The Infringement Coordination Group found that the pilot had followed the CAA’s advice to use a moving map and employing the use of a Frequency Monitoring Code (FMC) rather than squawking 7000 and not monitoring a frequency.
The pilot was open and honest in his report, stating that that despite thorough planning he had become distracted, by his passenger at the start of his flight. This led him to not setting the correct QNH which resulting in him flying higher than planned and flown. Distraction also played a played a part in his incorrect use of a moving map pre-flight and in-flight.
However, thanks to the effective use of a Frequency Monitoring Code (FMC), the infringement was quickly resolved with no requirement to apply safety intervention measures to Gatwick inbounds or departures. This textbook application of an FMC allowed the early resolution of an airspace infringement in a busy volume of airspace.
- An Aeronautical Information Circular (AIC Y116/2019) was issued on 29 August 2019 outlining the use of FMC in the UK. This can be found on the NATS Aeronautical Information Service website at http://www.nats-uk.ead-it.com
- A printable A5 card with the codes and associated frequencies is available to download: Listening squawks A5 card
Infringement of RAF Syerston Aerodrome Traffic Zone (ATZ)
Background
In November 2018, a C152 pilot departed Gamston aerodrome to fly to Leicester aerodrome. His planned route would have taken him to the west of Syerston. The pilot’s intention was to fly on a track of 210º from Gamston and turn onto 180º degrees when just past Ollerton (5.5 nm southwest of Gamston aerodrome) towards Leicester. The flight took place in mid-afternoon and the low sun was affecting visibility to the west. The pilot was not equipped with any electronic navigational aid such as a moving map.
RAF Syerston is a government aerodrome with an ATZ of 2 nm radius extending to 2000 ft agl (2,231 ft amsl) lying in Class G airspace. It is served by an Air/Ground (A/G) radio service on 128.525 MHz. The aerodrome is used for glider operations. Gliders are launched by winch and by aero-tow. Winch launch activity takes place up to 3,300 ft amsl and is charted as such with a G symbol on the 1:250,000 and 1:500,000 VFR charts along with the A/G frequency. As with all military ATZ, the details are notified in the UK AIP ENR 2.2.
The flight
The C152 pilot
Outbound from Gamston, as he climbed past 1,500 feet, it became apparent to the pilot that visibility was poor to the south and west. The pilot descended to remain visual with the ground. He believed he turned early and flew on a more south-easterly track than planned. In receipt of a Basic Service from East Midlands Radar, the controller told the pilot that Syerston was active and repeated it to him shortly afterwards. When the pilot encountered a glider in his 12 o’clock, he climbed and manoeuvred to maintain separation. He estimated that the two aircraft had passed within 300 feet of each other but was satisfied that there was “no danger of collision”.
The pilot stated that flying conditions had been difficult. Visibility was poor with low sun. He had ended-up five miles east of where he thought he was. Analysis of radar data showed that the aircraft had flown over Southwell, directly through the Syerston ATZ and overhead the aerodrome to Bottesford. The route had taken the C152 overhead the glider site at 1,578 feet amsl.
The glider pilot
The glider pilot was conducting an exercise within the ATZ at about 1,100 feet and flying northwards. He saw an aircraft flying towards him, over the launch winch, no more than 100 feet above and 500 feet away laterally from his glider. The pilot assessed that the aircraft would come close to him if he did not do something and so he rolled the glider to the right to create distance. The aircraft passed the glider about 100-200 feet to the left and at a similar altitude. The winch operator reported to the pilot that there was an aircraft above him and consequently a glider launch was stopped whilst the unknown aircraft was within the ATZ.
Learning Points
Risk of cable strike
The pilot overflew a glider site, albeit unintentionally, that was annotated on the chart with winch launch activity up to 3,300 ft amsl. A 4.5 mm Dyneema or steel wire in the air, when struck by an aircraft could have fatal consequences for both the aircraft impacting the wire and the glider, if still attached to the cable. Pilots must plan to avoid glider, and other aerial sporting, sites and be aware of what lies along and in proximity of their intended route and near any planned alternates. Check the VFR charts when route planning; a glider site is annotated on the chart as a G in a circle. If winch launching takes place at the location, a figure in thousands of feet will be annotated with the G. For example G/3.5 signifies winch launching to 3500 ft amsl. Where the site is hang or para gliding with winch launching, the chart symbol will be shown with the altitude.
Pilots should be aware that the vertical extent relates only to the maximum altitude of the cable and not to the maximum altitude to which glider, hang gliders or paragliders may be encountered.
Use of a moving map
This is another example of a serious airspace infringement where the pilot was not using a moving map. 85% of analysed airspace infringements in 2017 could have been prevented with the use of such a device. This aid to planning and navigation increases the pilot’s situational awareness considerably thereby allowing more capacity for operating the aircraft and communicating; in essence making navigation more simple. However, with sole use / over-reliance of moving maps, standard navigation skills can fade. When using a moving map it is good practice to have the route marked on a current aviation chart in case the system fails. Similarly, when refreshing chart and VRP navigation, it is good practice to have a moving map as a back-up.
When using moving maps, although the gliding symbol is reasonably clear the difference in presentation from the CAA chart is significant. Pilots are to be aware that on some moving maps:
- There may be no indication of winch launching.
- There may be no information of the maximum height of winch launches.
- There may be no warnings of intense gliding activity.
To see the required information on activity at the sporting aviation site the pilot must select the site by touching the symbol on the chart to open the dialog box. In addition, pilots must check their APP settings to ensure that they have not de-selected sporting aviation. By doing so, the pilot becomes totally oblivious to any risk.
Met conditions
Both pilots stated that the low sun was affecting visibility. The C152 pilot added that flying conditions had been difficult. Whilst the SERA VMC minima of 5 km visibility may be reduced to 1500 m if flying by day and at 140 kts or less and below 3000 ft for flights outside controlled airspace, pilots must apply Threat and Error Management when deciding if they are going to fly or continue with their flight. When flying at 90 kts, an aircraft takes less than 33 seconds to fly 1500 m.
Pilots, especially inexperienced pilots or those with low-hours must recognise the threats associated with flying at the minima. Faced with the same met conditions, the C152 pilot stated that he would now return to the airfield (of departure). It is important to know the legal limits as well as your own limits – do not ‘press on’.
Rule 11 of The Rules of the Air 2015
Aerodrome Traffic Zones (ATZ) are established under Rule 11 to are established to give protection to aircraft at the critical stages of flight when departing, arriving and flying in the vicinity of an aerodrome.
The Stansted radar controller reports there were multiple aircraft inbound to London Stansted Airport landing on Runway 04. An aircraft (Cessna) was observed to enter the Stansted TMZ 2 with no Mode Charlie. The first inbound aircraft continued its approach as separation was increasing due to the speed difference. Two subsequent inbounds were issued radar vectors to remain clear of the infringing aircraft and traffic information was passed to the Stansted inbounds. The Cessna was traced using Mode S and the North Weald air ground operator was asked to transfer the aircraft to the Stansted Controller’s frequency to enable the arrival sequence to be restored. The Cessna failed to change frequency; one Stansted inbound was radar vectored to Runway 22 and the other was able to recover to Runway 04.
The Cessna pilot reports being on a local VFR recreational flight from North Weald to Duxford routing via the north of BPK. The pilot reports forgetting to check that Mode C (ALT) was selected before departing. The reported normal operating procedures for club aircraft is to always leave the ALT mode selected on. The previous pilot had not complied with this procedure and had selected ALT off. The operating pilot did not note the transponder setting and failed to follow the checklist prior to departure.
The CAA’s Infringement Coordination Group (ICG) noted that the Cessna flew into the Stansted TMZ 2 displaying No Mode C information resulting in an airspace infringement. This ensued from the pilot not selecting ALT on the transponder having failed to carry out correct pre-take-off checks. This simple, yet essential step when operating within a TMZ resulted in a significant increase in workload for the Stansted controller and the development of a complex traffic situation during a busy ‘arrival phase’. The ICG also commented positively on the pilot’s open and honest reporting.
SERA PART C – effective 12 October 2017
SERA.13001 requires the pilot of an aircraft equipped with a serviceable SSR transponder to operate the transponder at all times during flight, regardless of whether the aircraft is within or outside airspace where SSR is used for ATS purposes.
Avoiding action by Commercial Air Transport
The Stansted radar controller reports observing an unknown aircraft track through the northern Stansted CTA (CTA 1) at 1900 feet and enter the Stansted CTR tracking in a westerly direction. Mode S identified the aircraft as a Cessna; a blind transmission was made in an attempt to establish communications with the infringing aircraft. A ‘check west’ was put in place meaning that all departures were suspended to the west; when the Cessna turned towards Andrewsfield, a ‘check all’ was put in place thereby suspending all departures. However, an eastbound departure was already rolling; on initial RT contact, the departing aircraft was given an immediate avoiding action turn to remain clear of the infringing aircraft.
The Cessna pilot reports being on a local VFR recreational flight from Andrewsfield routing to Bury St Edmonds, Newmarket and Sudbury and back to Andrewsfield to fly the hours required for licence revalidation. Despite reviewing the TAFs before flight, the pilot encountered deteriorating weather conditions on the first half of the flight; however, on turning to the next point, visibility improved so the pilot continued along the planned route. Along the sector, visibility deteriorated and a decision to return to Andrewsfield was made. The continued deterioration in weather resulted in the pilot being unable to recognise ground features that were expected. The pilot was not flying with a moving map and stated that a decision to abort the planned route was made too late.
The CAA’s Infringement Coordination Group (ICG) noted that the Cessna pilot lost situational awareness (SA) as to the aircraft’s position due to a deterioration in weather which resulted in an airspace infringement. When conditions deteriorated the pilot did not make use of one of 2 ATC agencies (Farnborough LARS or Essex Radar) or D&D to assist in recovery to Andrewsfield. Whilst it was felt that the route was planned effectively using a 1:500,000 Chart, insufficient Threat and Error Management was employed nor was the pilot using a moving map. The pilot’s honest reporting reiterated the need for moving map and not to get focused on fulfilling the task (in this case ‘hour building’) to the detriment of maintaining situational awareness. This was a prime example when the use of a moving map would have assisted the pilot in maintaining/recovering SA. In addition, early use of the Frequency Monitoring Code (listening squawk) for Stansted (7013) by the Cessna pilot on the inbound leg to Andrewsfield would have allowed the radar controller to resolve the airspace infringement at a much earlier point. Early avoiding action, to the departing traffic, by the radar controller prevented a loss of separation occurrence.
Avoiding action by Commercial Air Transport
The Solent radar controller reports observing an unknown aircraft northwest of the CTA (base level 2500 feet) tracking southwest towards controlled airspace on a definite course to infringe. Liaison was carried out with the Southampton Aerodrome Controller to give avoiding action to an aircraft on departure. Subsequently, the departing aircraft was given avoiding action by the tower controller to turn east. The infringing aircraft continued to track a further 3nm into the CTA prior to turning onto a north-westerly heading and leaving controlled airspace. The aircraft was later seen to select an adjacent LARS unit’s SSR code. Due to prompt avoiding action no loss of separation occurred.
The Piper pilot reports being on a local VFR recreational flight operating between 3000 feet and 4000 feet. The pilot was navigating using a 1:500 000 chart and was not using a GPS or moving map. The pilot decided to carry out an orbit over the radio telescope at Chilbolton to view the site; a gentle left-hand orbit was selected. The pilot added that a mistake was made in selection of the turn which resulted in the pilot infringing the Solent CTA; it was added that his could have been avoided by more detailed flight planning.
The CAA’s Infringement Coordination Group (ICG) noted that the Piper pilot did not carry out effective and thorough pre-flight planning and could have been better equipped for the flight. This resulted in a failure to avoid adjacent airspace whilst manoeuvring.
This infringement occurred due to insufficient Threat and Error Management during the planning and execution phases of the flight. Had the pilot used of the Frequency Monitoring Code (listening squawk) for Southampton/Solent (7011), the controller could have employed ‘defensive controlling’ by warning the pilot that they were about to infringe. Alternatively, had the Piper pilot been in receipt of an ATS from one of the many Units in the area, a warning may have been given (NOTE. Under a basic service, a controller may not have identified the aircraft despite the pilot being issued with an SSR code). Additionally, the airspace in that location is complex with CAS, ATZ, MATZ and Danger Areas. The proper use of a moving map would have assisted in flight planning. It would have also alerted the pilot both to the notified airspace itself and to the fact that the ‘gentle turn’ was not effective in avoiding it. Early avoiding action during a critical stage of flight, to the departing traffic, by the controlling team prevented a loss of separation occurrence.
Avoiding action by Commercial Air Transport
The radar controller 1 reports observing an aircraft (a DA40) squawking the conspicuity code for a nearly aerodrome 12nm south of Gatwick heading northeast, climbing through 3300 feet into the London TMA CTA (base level 2500 feet). At the time an aircraft was departing Gatwick on a southerly departure; the Gatwick departure was turned left, and to the southeast, to maintain radar separation. Due to a timely turn, no loss of separation occurred. Coordination was carried out with DA40’s controlling agency and the aircraft was transferred to the radar controller. Identification was carried out and Mode C was verified; the aircraft subsequently turned southbound and descended out of the London TMA.
The radar controller 2 reports there were multiple aircraft inbound to London Gatwick Airport landing on Runway 08. One aircraft was turned downwind for Runway 08 when CAIT altered the controller to an infringement. The inbound aircraft’s descent was stopped at FL75 to maintain radar separation. The aircraft was given further descent once lateral separation had been established. A second inbound aircraft was issued a non-standard turn from the hold to maintain radar separation.
The DA40 pilot reports being on a IFR training flight from Shoreham. On the taxy out to the runway for departure, the plan was changed to fly an improvised procedure to make the flight shorter. On passing 1000 feet, in the climb to 2200 feet, the Instructor began to turn what was thought to be the VOR CRS knob. However, the knob that was being operated was the BARO control for the primary altimeter; this resulted in a change of altimeter setting, from recollection, from 1023 HPa to 1003 HPa. The student continued the climb and levelled-off at an indicated altitude of 2300 feet. Attempts were made to establish communications with Farnborough LARS but due to frequency congestion the pilot returned to the departure aerodrome’s frequency at which time the standby altimeter was observed to show the aircraft was inside controlled airspace. An instruction to contact the Gatwick controller’s frequency was immediately received. On initial contact, and on receipt of a squawk for identification, the pilot commenced an emergency descent to below controlled airspace, and southbound turn, prior to returning to the Shoreham frequency. The GPS equipment was not displaying any map during the flight.
The CAA’s Infringement Coordination Group (ICG) noted that the DA40 pilot did not carry out effective planning to fly an improvised procedure effectively; this was exacerbated by poor operation of the aircraft’s flight instrumentation during an IFR training flight. The result was a major infringement into the London TMA and into conflict with 3 aircraft. Early avoiding action to 2 aircraft (one departure and one arrival) by the Gatwick controlling team prevented a loss of separation occurrence; another aircraft was delayed using a non-standard turn from the hold. A last-minute change to the flight profile resulted in insufficient pre-flight planning and crew briefing. A subsequent inadvertent, incorrect altimeter setting resulted in the student thinking the aircraft was lower than it actually was and climbed into controlled airspace and into airborne conflict.
Tips for avoiding infringements: Plan B, in this case the change to the intended procedure, was made too late and its execution was ineffective.
Background
In September 2018, a C172 pilot departed Wellesbourne Mountford to fly to Duxford; his planned route was via the DTY VOR, Cranfield, Old Warden and Royston. He had planned the flight to take place in August, but it did not take place due to poor weather.
He undertook the flight in September and infringed Luton controlled airspace on four occasions causing multiple losses of separation and disruption to aircraft which were broken off approach, issued with vectors and issued speed restrictions to remain clear of his aircraft. Departures from Luton Airport were suspended three times.
The C172 pilot, concerned that he had become over-reliant on using moving map/GPS technology, had decided that he would navigate using a chart and visual reference points. He used the same PLOG that he had prepared for the flight in August. In August, the winds were 260-280/6kts; on the day of the flight, Luton Airport was using Runway 08 and, at the time of his morning flight, the wind at 2,000 ft was north/northeast at 5 kts, increasing to 15 kts for his return flight in the afternoon.
The Flight
Outbound from Wellesbourne Mountford, after flying 40 nm, the pilot was 30 degrees right of track and some 14 nm south of the planned position. Instead of being overhead Cranfield, the pilot was overhead Cheddington.
Prior to the first uncleared entry into controlled airspace, an inbound aircraft to Luton Airport had its descent stopped as a precautionary measure. The C172 entered the Luton CTA at 3,000 ft and flew along the final approach to Runway 08. This required avoiding action to be issued to the inbound aircraft. Despite the turn, separation was lost. Two other inbound aircraft were issued with control instructions to ensure that separation was maintained. The infringing aircraft then entered the Luton CTR necessitating all departures from the airport to be suspended. The C172 left controlled airspace to the south, between Hemel Hempstead and St Albans.
Unsure of his position and thinking he was over the M11 (the aircraft was actually over the M1), the pilot called D&D and advised he was lost. The pilot was told he was over Hemel Hempstead and requested ‘a fix for Duxford’. The pilot could not locate Hemel Hempstead on his chart as it was on the fold. When asked, the D&D assistant advised the pilot that Duxford was 29 nm to the northeast. The pilot followed the bearing for Duxford. Six minutes after leaving controlled airspace, the C172 re-entered the Luton CTR on a north-easterly heading. Departures from Luton Airport were suspended again. The C172 flew within approximately 1nm of the runway at Luton Airport. Departures resumed when the aircraft left controlled airspace 8 minutes later.
The return flight was unplanned; the pilot intended to reverse the route. The flight was going to plan until the ATC unit at Cranfield aerodrome requested the pilot flew further south. The C172 entered the Luton CTR at 2,500 ft, in the vicinity of Letchworth Garden City. Departures from Luton Airport were suspended for a third time. Two losses of separation occurred: an aircraft that was airborne from Luton Airport came within 1.1 nm of the C172 and an aircraft on approach lost separation with the C172, which was flying parallel to Runway 08 at 2,100 ft. The C172 continued to the west and left controlled airspace in the vicinity of Dunstable 4 minutes after entering.
Learning Points
Use of a Moving Map
Standard navigation skills can fade with over-reliance of moving maps and GPS. However, this would be recognised through Threat and Error Management. In this case when the pilot was refreshing his use of a chart and VRPs, using a moving map as a back-up would have provided him with immediate in-cockpit assistance and route confirmation.
When using a moving map it is good practice to have the route marked on a current aviation chart in case the system fails. Similarly, when refreshing chart and VRP navigation, it is good practice to have a moving map as a back-up.
These flights were not instructional. But the ICG has noted that many instructors who have infringed airspace did so whilst not using a moving map. When used properly a moving map can help establish and maintain situational awareness. Especially in a high-workload environment where attention is divided over more tasks than during recreational flying.
85% of analysed airspace infringements in 2017 could have been prevented with the use of correct use of a moving map.
Use of the Luton Frequency Monitoring Code (FMC/Listening Squawk)
The Luton Radar controller tried on numerous occasions to contact the pilot but the he was neither employing the FMC nor was he listening out on the Luton Frequency.
Whilst this may not have prevented the airspace infringements from occurring, an earlier resolution would have been possible and the impact of the infringements would have been less.
45% of analysed airspace infringements in 2017 could have been prevented with appropriate use of an FMC.
Use of D&D
A better understanding of what to ask D&D when lost could have prevented the 3rd airspace infringement.
Pilots should practise communication with D&D on 121.5 MHz to ensure that they are competent and confident at all times when using this service.
Planning
Every flight, no matter how many times it has been made before, should be planned in detail prior to departure. This includes, but is not exclusive to, reading NOTAMS and associated Aeronautical Information Circulars and Supplements referred to in the NOTAM, checking relevant aerodrome information and gaining a thorough understanding of the forecast and prevailing met conditions.
In this case, the winds were 90 degrees different to those when the flight was planned 2 weeks earlier. Failure to plan amounts to planning to fail.
