Flying in the Stansted area

Preventing airspace infringements in the vicinity of Stansted

This infringement update is the sixteenth in a series of narratives focusing on identified infringement ‘hot-spots’ in the UK. It has been written by members of the Stansted Local Airspace Infringement Team. This narrative has been updated August 2023.

In 2022, there were a total of 110 infringements of the 3 notified airspace types at Stansted: 44 were in the Control Areas (CTA), 23 were in the Control Zone (CTR) and 43 were in the TMZs. Infringement hot-spots have been identified as TMZ-2 and CTA-2.

In early 2009, the CAA approved the establishment of two Transponder Mandatory Zones (TMZ) around Stansted Airport  resulting from overriding safety concerns in relation to the number, and severity, of airspace infringement risk of the two  CTAs adjacent to the CTR reported in previous years. The introduction of the TMZs in September 2009 negated any additional controlled airspace to be introduced but enhanced controller situational awareness and safety.

Over ten years later despite many pilots correctly adhering to the requirements, reports of infringements of the TMZ and Stansted controlled airspace continue to be submitted. Why are there still, on average, two infringements of Stansted notified airspace per week?

Transponder Mandatory Zones

TMZs 1 & 2 are co-incident with the lateral boundaries of CTA-1 (north-east) and CTA-2 (south-west) of the Stansted CTR. They are Class G airspace from the surface to 1,500 feet AMSL and are subject to UK SERA.6005 and therefore are notified airspace in relation to airspace infringements.

Access to the Stansted TMZs, without ATC approval, requires a serviceable Mode S Elementary transponder to be operated at all times and to its full extent. Within the TMZs, pilots are recommended to obtain a service from Farnborough LARS North (132.800 MHz) or maintain a listening watch on Stansted Radar (120.625 MHz) and make use of the Frequency Monitoring Code (FMC) of 7013.

The Air Navigation Service Provider (ANSP) facilitates access into the TMZ for those pilots whose aircraft do not meet the transponder requirement. The UK AIP publishes the requirements to operate within the TMZ in GEN1.5 (AIRCRAFT INSTRUMENTS, EQUIPMENT AND FLIGHT DOCUMENTS) paragraph 5.3.1(f); these requirements are reproduced in the various commercial flight guides.

If you wish to operate in a Stansted TMZ without a serviceable Mode S transponder or without any form of transponder, access may still be granted subject to specific ATC approval from either:

• Farnborough Radar on 132.800 MHz between 0800 hours and 2000 hours UTC; or
• Stansted Radar on 120.625 MHz at other times.

The procedures for Farnborough Radar to co-ordinate with Stansted Radar may result in short delay so an awareness of this fact in the pre-flight planning stage should be remembered and incorporated into your Threat and Error Management (TEM). Make a call with sufficient time to allow for a delay in receiving a clearance.

TMZ Infringements

When an unknown aircraft is detected within a TMZ there is a significant workload increase for the controller including a set procedure to be followed with co-ordination. Although Class G airspace, all un-identified primary only or Mode A-only returns will be treated as an airspace infringement;  air traffic controllers must maintain separation of 3NM laterally or 3,000 feet vertically (when the altitude is indicated) between the infringing aircraft and any aircraft to which they are providing a service. If necessary ‘Avoiding Action’ may be passed to arriving and departing aircraft if already airborne or departing aircraft may be held on the ground and delayed depending upon the position of the unknown aircraft. A ‘Loss of Separation’ is recorded when it’s not possible to maintain 3NM laterally or 3,000 feet vertically from the unknown aircraft.

If you intend to visit any of the airfields near the TMZs, it is a good idea to review the arrival and departure procedures online and in VFR flight guides; you may be required to obtain a specific briefing from the airfield operators to ensure compliance of the agreed local ATC procedures. When you PPR/book into the aerodrome, ask the ANSP  staff of any specific procedures that need to be followed.

Further information relating to the Stansted TMZ can be found in UK AIP EGSS AD2.2.7

Stansted Controlled Airspace

Although many pilots comply with the TMZ procedures, there are still reported infringements of CTA-1 and CTA-2 when pilots have climbed from the TMZ into the CTAs or flown through the corner of the CTR boundary.

The controlled airspace complex comprises the CTR and 4 CTA, levels depicted below. All airspace is Class D. The Class A London Control Area (LTMA) is contiguous from the upper CTA levels to FL195.

CTA-1 and TMZ-1 northeast of the Stansted CTR

CTA-2 and TMZ-2 southwest of the Stansted CTR

CTA-4west of the Stansted CTR adjoins the Luton CTA

CTA-3 east of the Stansted CTR

Stansted has 15 Visual Reference Points (VRPs); all are signposted in UK AIP EGSS AD2.22.6; changes made in 2023 are now depicted on the latest VFR charts. For those pilots who use radio navigation techniques to navigate by, or as a back-up to visual navigation, there are 3 VOR/DME nearby to assist with cross-referencing positions from notified airspace boundaries:

If routeing between the Stansted and Luton CTRs, flying below altitude 2,500 feet direct between the VOR/DME of BPK and BKY, keeping to the west of the Ware and Puckeridge A10/A120 Interchange VRPs will ensure that you will not infringe Stansted controlled airspace.

In Threat and Error Management (TEM) terms, infringing controlled airspace is a ‘Threat’ then perhaps the ‘Error Management’ is utilising these NAVAIDs to assist with navigation.

Prevent an airspace infringement

The Airspace and Safety Initiative website provides extensive advice on how to avoid the risk of infringing airspace. Airspace infringements can be avoided by effective pre-flight planning, sound inflight decision making underpinned by the application of TEM. Below are some general Threats and Errors for Stansted Airspace and those that are more specific to aerodromes positioned within or beneath it.

North Weald

(See hot-spot narrative 38: North Weald Aerodrome)

Andrewsfield

Audley End

Hunsdon

(See hot-spot narrative 35: Hunsdon Microlight Site)

 In addition, pilots are strongly encouraged to:

Use a Moving Map which will provide a profile along your planned route showing the controlled airspace boundary and associated visual and aural warnings as you approach the airspace. When flying in proximity to Stansted controlled airspace, and if able to, Take 2.

Obtain an air traffic service from Farnborough North on channel 132.800 MHz.

Use a Frequency Monitor Code (FMC). Rather than squawking 7000/2000, if you do not want to obtain a service from ATC, use an FMC appropriate to the direction of flight; the Stansted FMC is 7013 with Stansted Radar (120.625 MHz). There are a further 3 FMCs in use in the vicinity of Stansted’s controlled airspace.  Review the chart at ENR6.80 to understand the boundaries of the areas; this information is also replicated in AIC Y100/2022.

Use the correct QNH. Obtain the Stansted QNH from the ATIS (127.180 MHz) or monitor Stansted Radar (120.625 MHz). ATIS also available on Clacton VOR (on frequency 114.550 MHz/channel 92Y).

Make a Detailed Plan. Build in your climb and descent points when planning your route. Use satellite imagery to know what VRPs look like and what airspace lies above them or close by. Prepare a PLOG listing frequencies of useful adjacent ATSU/aerodromes that may need to be called such as:

If appropriate – request a clearance. If for any reason a climb into the CTA, or a turn into the CTR is (or may be) required then a clearance must be obtained from Stansted Radar before entering controlled airspace.

Air Traffic Controllers are there to help. If in doubt, contact Stansted Radar on 120.625 MHz for assistance.

Infringement statistics analysis has identified a trend in infringements of Stansted airspace. This hot-spot narrative is the first in a series covering satellite airfields around Stansted controlled airspace. It is intended to provide guidance to help pilots visiting Hunsdon prevent airspace infringements.

DOWNLOAD Hunsdon Area of Operation A5 card

Hunsdon Microlight Site is located at 51’48’25°N 000’04’16°E, inside the south-western edge of the Class D Stansted Control Zone (CTR) approximately 7.5 NM from London Stansted Airport on a bearing of 232°. The site is adjacent to the Stansted Transponder Mandatory Zone (TMZ-2) and has an Area of Operation (AoO) which is established to facilitate flight within TMZ-2 for aircraft unable to comply, and flights into and out of Hunsdon without a specific class D entry clearance from Stansted Radar.

Chart extract from 1:500k Sheet 2171CD SOUTHERN ENGLAND AND WALES Edition 49 (2023)

Note: Hunsdon location is corrected in UK AIP ENR 5.5 to depict inside the Stansted CTR as of AIRAC 03/2023

Stansted controlled airspace structures

Hot-spot narrative 16: Stansted CTA, CTR and TMZs provides a detailed article on preventing airspace infringements of the controlled airspace structures in the vicinity of Stansted Airport.

Hunsdon is located within the Class D Stansted CTR, active surface to 3500 feet AMSL. Stansted has four Class D Control Areas:

• CTA-1 to the north-east
• CTA-2 to the south-west
• CTA-3 to the east/south-east
• CTA-4 to the west/north-west

In 2009, two TMZs were established which are co-incident with the lateral confines of CTA-1 and CTA-2; they sit underneath the CTAs from surface to 1500 feet AMSL. Luton CTA-1 is located to the north-west of Hunsdon.

Operating inside any TMZ, without ATC approval, requires a serviceable Mode-S elementary transponder to be always operated to its full operating capacity. This requirement is is notified in the United Kingdom Aeronautical Information Publication (AIP) at Gen 1.5 (GEN 1.5 AIRCRAFT INSTRUMENTS, EQUIPMENT AND FLIGHT DOCUMENTS).

Access to a TMZ can still be granted without a serviceable Mode-S transponder subject to ATC approval. Details on how to access Stansted TMZs without a serviceable Mode-S transponder can be found in the next section.

Chart extract showing airspace structures

Further information can be found within UK AIP EGSS AD 2.17.

Hunsdon procedures

Hunsdon is strictly a PPR airfield. It is a condition of the Stansted-Hunsdon Letter of Agreement that all visiting pilots must obtain a PPR brief over the telephone from a Hunsdon club officer, contact details can be found on the club website.

The AoO is established up to an altitude of 1000 feet AMSL to enable aircraft to operate into and out of the site without a specific Class-D entry clearance. In addition, the AoO allows flight within the TMZ without the requirement to operate a Mode-S transponder.

The AoO dimensions can be found in UK AIP EGSS AD 2.22.8.

Prior to departure

Ensure you have made a detailed plan, are familiar with the Hunsdon Circuit reference points and squawk 7010 if able.

Inbound and outbound procedures

Pilots operating into and out of Hunsdon should make transmissions on the SafetyCom frequency 135.480MHz, with calls made in accordance with CAP 413, prefixed “Hunsdon Microlight Traffic” and suffixed “Hunsdon”.

All Hunsdon aircraft must remain inside the AoO when operating inside the Stansted CTR. Pilots of aircraft equipped with a serviceable mode-S transponder can plan a route through TMZ-2 of their choice. Squawk 7010 when arriving and departing to allow Stansted Radar to know your intentions at Hunsdon.

All aircraft should operate on the Stansted QNH which is obtained from Stansted ATIS on 127.175 MHZ.

Operating without a Mode-S transponder

Aircraft that are not equipped with a Mode-S transponder must adhere to one of the following two options when inside TMZ-2:

1. Route via the Hunsdon AoO; or
2. Obtain a permission from either:

• • Farnborough Radar on 132.800 MHz between 0800 hours and 2000 hours UTC; or
  • Stansted Radar on 120.625 MHz at other times.

Aircraft wishing to operate within the TMZ, outside of the AoO, must gain specific ATC approval to transit the TMZ.

A TMZ permission is not required for aircraft routeing solely within the AoO. Entry and exit to the AoO and the surrounding Class G airspace is north of Visual Reference Point (VRP) Ware and south of the village of High Cross. To remain inside the AoO, pilots are advised to remain northeast of the water at Stansted Abbotts and west of the electricity pylons.

Further information on operating inside Stansted TMZs can be found in this leaflet: Stansted TMZ

The procedures for Farnborough Radar to co-ordinate the request with Stansted Radar may result in a short delay for a permission to be granted which should be taken into consideration at the pre-flight planning stage.

Hunsdon moving map

Hunsdon AoO

Circuit Procedures

Aircraft operating at Hunsdon should do so on the Stansted QNH as the AOO ceiling is 1000 feet AMSL on the Stansted QNH. It is recommended to apply the ‘Take 2’ guidance – remain 200 feet below the base of controlled airspace.

Pilots should be aware of the circuit reference points, highlighted on the chart below in yellow:

1. Hunsdon Farm Lodge (1) to the west,
2. Tuck’s Spring (2) to the southeast,
3. Powerlines (3) to the east and
4. Marshland Wood (4) to the north.

Due to the constrained nature of some circuit patterns, pilots of high-performance microlights may find some circuits for 08 and 32 challenging and training circuits by non-club students are not permitted. Glide descents are preferred where it is safe and practicable to do so.

Circuit reference points

Noise abatement areas

Noise abatement areas should be considered only when it is safe to do so. It is generally always safer to fly over noise abatement areas than to, for example, turn without sufficient airspeed or to infringe controlled airspace.

Noise abatement areas are depicted on the chart below in brown and are:

• The built-up areas of Hunsdon to the west of the airfield
• The farm to the northeast of the airfield
• The farmland to the north of Marshland Wood

Noise abatement areas

Visual Reference Points (VRPs) and notable features

Visual Reference Points (VRPs) and Notable Features

1. VRP Ware
   Approximately 3.5NM west of Hunsdon, Ware is a town which sits on the western boundary of the Stansted TMZ-2. It is identifiable by a large Sport Stadium/Athletics track to the north.
   Pilots operating in the AoO should remain north of Ware.
2. VRP Puckeridge (A10/A120 Interchange)
   VRP Puckeridge is a town approximately 5NM north-northwest of Hunsdon. It lies in in Class G airspace under the Stansted CTA-4, on its border with Luton CTA-1. The base of controlled airspace here is 2,500 feet AMSL.
3. Stansted Abbots Marina
   Southeast of Ware, Stansted Abbotts Marina is outside of the Hunsdon AOO and within the TMZ-2.
   Pilots operating in the AoO must remain to the north of the bodies of water.
4. High Cross
   A small village located approximately 4NM west-northwest of Hunsdon. It is to the west of the A10 road and lies in Class G airspace, just west of the boundary of TMZ-2.
   Pilots operating on the AoO should route south of High Cross and north of VRP Ware.
5. Pylons/Powerlines
   North/south powerlines mark the eastern AoO boundary.
6. Hunsdon House
   A stately home north of the powerlines, visible on climb-out from Runway 21, approximately 1NM from Hunsdon. The building is square and a flag usually flies on the roof. Located inside the AoO.

Frequencies

Airspace infringement prevention

It is important to be aware of avoiding airspace infringements, especially when operating in proximity to controlled airspace structure as at Hunsdon.

The following are general pieces of infringement avoidance advice to keep in mind during all flights and when you are planning your flight .

Apply Threat and Error Management (TEM) in both planning and flying

Identify threats you may face and errors that you may make. Threats could include airspace, weather, equipment failure or distraction and errors could involve navigation or incorrect instrument reading. Plan for how you would address each, so you are not surprised in-flight.

> Read more on TEM: Threat & Error Management

Plan your flight appropriately using regulated material

Study airspace structures along your route and make note of vertical as well as lateral dimensions. Be aware of using non-regulated, third-party materials as your sole source of planning – make use of regulated, up to date paper charts and NATS UK Aeronautical Information Service (AIS) to access NOTAM, the UK Aeronautical Information Publication (AIP) & Supplements and UK Aeronautical Information Circulars (AICs). In the UK, NATS AIS is the authorised source of UK aeronautical information provided on behalf of, and regulated by, the CAA

Plan your route to “TAKE2” – remain 200 feet from the base of controlled airspace and/or 2 NM from the edge. You could always increase this buffer in cases of thermic or windy conditions.

Correctly use a VFR moving map

Ensure your device’s chart is updated before you plan your route and that you carry a backup if your device was to fail in flight. Familiarise yourself with your Moving Map’s user guide. Moving Map technology should not be the sole means of planning or navigation as highlighted in the European General Aviation Safety Team’s Safety Promotion Leaflet, Using Advanced Navigation Technology Safely.

In flight, make sure that the moving map is within your field of vision, that it is showing airspace boundaries and that airspace alerts are enabled. Don’t cancel airspace alerts until you are completely aware of them and the associated TEM.

Make use of an Air Traffic Service or a Frequency Monitory Code (FMC)

Familiarise yourself with the different UK Flight Information Services available to you and the differences between a basic, traffic and deconfliction service. Make use of a Lower Airspace Radar Service (LARS) where available.

If operating proximate to controlled airspace and you do not want to obtain an air traffic service, listen to an appropriate frequency, and use the FMC rather than squawking 7000. This way, the unit will be able to contact you quickly should they need to.

In the case of Stansted, the Frequency is 120.625 MHz and the squawk is 7013 as annotated on the VFR chart.

Chart extract showing Stansted frequency and squawk ID

> Download listening squawks: Listening squawks

Infringement statistics analysis has identified a trend in infringements of Stansted airspace. This hot-spot narrative is the second in a series covering satellite airfields around Stansted controlled airspace. It is intended to provide guidance to help pilots operating at North Weald prevent airspace infringements.

DOWNLOAD North Weald Area of Operation A5

North Weald Aerodrome (EGSX) is located at 51°43’18″N, 0°9’15″E, approximately 10NM from Stansted Airport on a bearing of 197°. The aerodrome lies within the Stansted Transponder Mandatory Zone (TMZ-2) which extends from the surface to 1,500 feet AMSL and beneath Stansted Control Area (CTA-2). An Area of Operation (AoO) is established to facilitate flight at North Weald for aircraft unable to comply with TMZ requirements.

Figure 1: Chart extract from CAA 1:500k Sheet 2171CD Southern England and Wales Edition 49 (2023)

Controlled Airspace Proximate to North Weald

Figure 2: Chart extract from AD-2-EGSS-4-1 and table showing airspace structures

Area of Operation (AoO)

North Weald lies within Stansted TMZ-2, within which aircraft must carry and operate a serviceable Mode-S transponder (as per SERA.60005 (b)). An AoO is established up to 1500 feet AMSL to facilitate flight into and out of North Weald for aircraft unable to comply with the requirements of the TMZ.

The AoO is depicted below (Figure 3) and its shape comprises a circle of 2NM radius centred on 51°43’18″N, 0°9’15″E, with a “stub” to the southwest which extends approximately 1.5NM west of the eastern TMZ boundary. Epping Visual Reference Point (VRP) is within this stub.

Figure 3: Chart extract from CAA 1:250k Sheet 8 England South Edition 26 (2022) showing EGSX AoO

Aircraft without a serviceable Mode-S transponder must adhere to one of the following two options when visiting North Weald:

1. Route entirely via the North Weald AoO; or
2. Obtain a permission from either:
   • Farnborough Radar on 132.800 MHz between 0800 hours and 2000 hours UTC; or
   • Stansted Radar on 120.625 MHz at other times.

Aircraft without serviceable Mode-S wishing to operate within the TMZ, outside of the AoO, must gain specific Air Traffic Control (ATC) approval.

North Weald Procedures

Circuit Procedures

There are two reciprocal runways at North Weald, Tarmac/Concrete and Grass both orientated 02/20. Circuits are conducted to the west at 1,200 feet QNH. Due to the Stansted CTA above, overhead joins are not permitted.

Visual cues for the circuit can be seen below (Figure 5). To avoid an infringement of the Stansted CTR, pilots should make turns abeam or south of the M11 Junction 7 Roundabout. Aircraft unable to comply with TMZ requirements MUST turn at M11 Junction 7 to remain inside the AoO, see below (Figure 4).

All aircraft MUST remain south of The Church Langley Water Tower which lies on the boundary of the CTR (see Figure 5).

Figure 4: M11 Junction 7

Figure 5: EGSX circuit cues

M11 Junction 7 Roundabout from above.

M11 Junction 7 Roundabout from 1200 feet

Church Langley Water Tower

Airspace Infringements at North Weald

Due to the nature of North Weald’s location in relation to Stansted Airport, the impact of infringements in this area on Stansted Airport’s operations is high and often requires the implementation of safety intervention measures from ATC. These measures can include the issuing of traffic information, radar vectors or avoiding action or in the suspension/delay in departures. ATC must ensure that a minimum of 3NM or 3,000 feet is maintained between aircraft inbound to Stansted and any infringing aircraft. Should less separation be achieved a loss of separation occurs and the controller is suspended from controlling duties pending investigation.

Below (Figure 6) is a snapshot from the CAA’s Airspace Analyser Tool. Figure 6 illustrates aircraft tracks inbound to Stansted which were routed from the South over North Weald within CTA-2 at between 1,500 and 2,500 feet (AMSL) from 1 January 2023 to 22 June 2023. The lowest aircraft was recorded at 1,700 feet. The 3NM scale line highlights the radius that must be maintained around an infringing aircraft, as 3,000 feet separation would not be possible.

Figure 6: EGSS inbound tracks from the south at 1,500 feet – 2,500 feet, 1 January 2023 – 22 June 2023.

Types of infringement reported in the vicinity of North Weald

Vertically into CTA-2

Due to the airfield elevation of 321 feet, it is essential that you operate on the Stansted QNH to avoid entering the CTA above. You must ensure that climbs are arrested at the circuit altitude of 1,200 feet and you maintain a high level of monitoring of your altitude after departing the circuit, beneath the CTA.

Tips to avoid a vertical infringement of Stansted CTA-2

• Minimise distraction within the cockpit whilst climbing out, flying in the circuit and beneath the CTA to enable you the capacity to monitor your altitude. The concept of a ‘sterile cockpit’ is not limited to commercial aircraft operations.
• Remind yourself of the 1,200 feet circuit limit on your pre-departure checklist.
• Understand the impact of forecast weather on your flight. Thermic or turbulent conditions can inadvertently push you updwards. A strong headwind will result in a greater climb angle, as with reduced ground speed you will travel a shorter distance laterally before reaching 1,200 feet, which is important to consider if you use ground features as circuit turning points without referencing your altitude. Use the regulated Met Office Aviation Briefing Service in your planning.
• Only depart when you are comfortable and ready. Do not rush yourself into a gap in the circuit traffic to the detriment of your situational awareness. It has been found that rushing to depart in such a gap has often led to pilots forgetting to select their transponders on to ALT. Thereby leading to an infringement of the TMZ.
• Monitor your altitude after leaving the North Weald circuit – you are still flying under the CTA, when possible Take 2 – remain 200 feet below the base.

Laterally into the CTR

The Stansted CTR is less than 2NM on runway heading from the airfield boundary to the north northeast It is of particular importance when managing the workload of climbing out from Runway 02, however must also be considered when managing traffic ahead when downwind for Runway 20.

Tips to avoid a lateral infringement of the Stansted CTR

• Be aware of your ground speed – particularly if operating an aircraft with a higher relative performance than one you are used to, you’ll approach the CTR quicker.
• If safe to do so, turn abeam the M11 Junction 7 roundabout. This will give you a 1NM buffer from the CTR.
• If unable to turn at M11 Junction 7, you MUST ensure you turn prior to the Church Langley Water Tower. Your turn should be commenced prior to the built-up area of Church Langley west of the M11 to ensure it is completed before the water tower.
• Do not be pressured by limited gaps in the circuit. Departing too soon after a preceding aircraft (particularly one slower than you) will result in the need to extend your climb from 02 out for separation. When operating on Runway 20, consider slowing your cruise, going around at circuit height or leaving the circuit to avoid extending the downwind leg into the CTR.

Lateral into CTA-2

Overhead joins are not permitted at North Weald. You must plan how you will integrate with established circuit traffic ahead of time.

Tips to avoid a lateral infringement of Stansted CTA-2

• Do not plan to overfly North Weald if transiting TMZ-2, without having established two-way communications with North Weald Radio on 123.530 MHz. The circuit is often busy at 1,200 feet, leaving very little distance from the CTA above should you need to climb to avoid traffic. Overflying North Weald without establishing positions of circuit traffic increases the risk of a mid-air collision. Alternatively, request a clearance from Stansted Radar to transit the CTA above North Weald or obtain information from Stapleford Radio on 122.805 MHz to transit the Stapleford ATZ in accordance with Rule 11 (5) of the Rules of the Air Regulations 2015.
• Incorporate an easily identifiable limit point into your pre-flight planning, which is plotted on your chart and PLOG beyond which you won’t proceed until at circuit height to avoid last moment descents below the CTA or the effect of a strong tailwind. From the east such a limit point could be Chipping Ongar A414/B184 Interchange VRP or from the southwest M25 Junction 26.
• Increase your situational awareness by listening out on the North Weald Radio frequency (123.530 MHz) to establish a picture of the traffic situation at the airfield prior to arrival. Identify an area in your planning in which you can hold if the airfield traffic is high and wait until you have a full picture before commencing your join. Remember North Weald Radio is non-surveillance so should only be used when arriving, departing, or operating in the circuit.

TMZ-2

Aircraft operating at North Weald must either be Mode-S equipped, operate wholly within the AoO or obtain a permission from Farnborough or Stansted Radars (as detailed above.)

Tips to avoid an infringement of Stansted TMZ-2

• Check, check and check again. Include an ALT check on your checklist immediately prior to departure. Incorporate it into your checks once lined up, and once again when airborne, prior to leaving the AoO. Confirmation bias is a common causal factor in TMZ infringements.
• Incorporate an ALT check into your limit point identified at the pre-flight planning stage when inbound to the airfield. Do not proceed beyond until you have descended to circuit height AND checked your transponder is set to ALT.
• Check your transponder is within limits. Farnborough LARS can advise if your Mode-C is displaying erroneously against your altimeter. The maximum error of altitude encoder and transponder equipment can be no more than +/- 125 feet.
• Request a permission to transit the TMZ if your transponder is in-operational or out of limits (as detailed above), or if you are uncertain of its operational status in-flight.

How to avoid airspace infringements

Apply Threat and Error Management

Identify threats you may face and errors that you may make. Plan for how you would address each, so you are not surprised in-flight.

Threats at North Weald include:

• Notified airspace: Stansted CTA-2, Stansted TMZ-2, Stansted CTR or Stapleford ATZ
• Other aircraft: the area in the vicinity of North Weald and Stapleford can become very congested with traffic of varying performance levels.
• Distraction, for example from passengers or technical issues. Workload is high in the vicinity of North Weald and you must be wholly focused on the flying task. See Safety Sense Leaflet 31 on Distraction and Interruption

Errors you could make at North Weald include:

• Operating within the TMZ, outside of the AoO, without an operational Mode-S transponder displaying ALT information.
• Extending your climb-out (from Runway 02) or downwind (Runway 20) leg, leading to an inadvertent entry into the CTR.
• Losing situational awareness as to your lateral and vertical position relative to CTA-2.
• Fail to formulate a contingency plan (a ‘Plan-B’ ) in your pre-flight planning. The airspace in this area can be very busy, including limit points in your plan can create more time in the air to manage the workload.

> Read more on TEM: Threat & Error Management

Plan your flight appropriately using regulated material

Study airspace structures along your route and make note of vertical as well as lateral dimensions. Be aware of using non-regulated, third-party materials as your sole source of planning – make use of regulated, up to date paper charts and NATS UK Aeronautical Information Service (AIS) to access NOTAM, the UK Aeronautical Information Publication (AIP) & Supplements and UK Aeronautical Information Circulars (AICs). In the UK, NATS AIS is the authorised source of UK aeronautical information provided on behalf of, and regulated by, the CAA.

Where able, plan your route to “TAKE2” – remain 200 feet from the base of controlled airspace and/or 2 NM from the edge. You could always increase this buffer in cases of thermic or windy conditions.

Obtain an appropriate Air Traffic Service or use a Frequency Monitoring Code (FMC)

Familiarise yourself with the different UK Flight Information Services available to you and the differences between a basic, traffic and deconfliction service. Make use of a Lower Airspace Radar Service (LARS) where available.

If operating proximate to controlled airspace and you do not want to obtain an air traffic service, listen to an appropriate frequency and use the FMC rather than squawking 7000. This way, the unit will be able to contact you quickly should they need to.

Whilst operating proximate to Stansted, make use of the Stansted FMC. The Frequency is 120.625 MHz and the squawk is 7013 as annotated on the VFR chart (see Figure 7). Alternatively, within the TMZ obtain a service from Farnborough LARS North on 132.800 MHz.

Figure 7: Chart extract showing Stansted CTR, CTA-2 and TMZ-2 with FMC annotation.

Correctly use a VFR Moving Map

Ensure your device is connected to wifi and the charting is updated before you plan your route and that you carry a backup if your device was to fail in flight. Familiarise yourself with your Moving Map’s user guide. Moving Map technology should not be the sole means of planning or navigation as highlighted in the European General Aviation Safety Team’s Safety Promotion Leaflet, Using Advanced Navigation Technology Safely.

In flight, make sure that the moving map is within your field of vision, that it is showing airspace boundaries and that airspace alerts are enabled. Don’t cancel airspace alerts until you are completely aware of them and the associated TEM.

Further information on Stansted Controlled Airspace can be found in Hot-Spot Narratives:

• 16. Stansted CTA, CTR and TMZ
• 35. Hunsdon Microlight Site