While we understand that many pilots are currently unable to fly due to COVID-19 restrictions we aim to continue to release safety education and awareness material to support the GA community with the future return to flying and promote longer-term safety awareness. To meet that aim we are continuing to publish information relating to airspace infringement hot-spots.
Focus on Redhill — Preventing Airspace Infringements in the vicinity of Gatwick
This update is the fifteenth in a series of narratives focusing on identified infringement hot-spots in the UK. It has been written by members of the Gatwick Local Airspace Infringement Team.
In 2019, there were 77 infringements of Gatwick Controlled Airspace (CAS); 54 were in the Control Area (CTA) and 23 were in the Control Zone (CTR). Every month of 2019 saw at least one infringement of the Gatwick Controlled Airspace (CAS) by an aircraft operating to or from Redhill. Some of these were navigational errors, pilots entering the Gatwick CTR without permission, however many were vertical infringements of the CTA caused either by inaccurate height keeping or inaccurate altitude reporting equipment. Any infringement may result in an immediate safety risk with arriving or departing traffic, ‘go-arounds’ and disruption to thousands of passengers from one of the busiest single runway operations in the world. Airspace infringements can be avoided by effective pre-flight planning, sound inflight decision making underpinned by the application of Threat and Error Management (TEM).
The CTR extends from the Surface to 2,500 feet amsl with the CTA extending from 1,500 feet amsl to 2,500 feet amsl; both are Class D airspace. The Class A London Control Area (LTMA-1) extends upwards from 2,500 feet amsl to FL195.
Redhill Aerodrome is approximately 4.5NM northeast of London Gatwick. The southern half of the Aerodrome lies within the Gatwick CTR and the northern half beneath the Gatwick CTA. An ATC service is provided by Redhill Tower on Channel 119.605; there is no requirement to contact Gatwick ATC for an entry clearance as long as flights are made within the published Local Flying Area (LFA) joining or leaving via one of the Visual Reference Points (VRPs); in accordance with the published Redhill procedures. To reduce the chances of pilots using an incorrect altimeter setting all procedures are based on the Redhill QNH. The LFA is not coincident with the Aerodrome Traffic Zone (ATZ). The ATZ is a non-standard shape and the maximum altitude within the ATZ is 1,400 feet QNH unless otherwise co-ordinated with Gatwick ATC. The LFA and associated procedures are published in the UK AIP EGKR AD 2.22 FLIGHT PROCEDURES (section 3).
The VRPs are:
- Junction 7 M25/ Junction 8 M23;
- Godstone (the southern tip of Godstone town);
- Godstone Railway Station (the railway station in South Godstone not in Godstone);
- Buckland (the lake to the West of Reigate)
The southern boundary of the Redhill’s non-standard ATZ is 3NM north of, and parallel, to the Gatwick extended runway centreline. Any excursion from the ATZ or the LFA extension to the West of the ATZ create a risk to the Gatwick operation resulting in ‘go-arounds’, disruptions, delays impacting the airport and airlines.
A ‘Loss of Separation’ is recorded when it’s not possible to achieve 3NM or 3000FT from the unknown aircraft.
The location of Redhill Aerodrome is a key factor in the airspace infringement risk. This is important when Runway 18/36 is in use, especially when 36 is used with a strong northerly wind.
Runway 18 departing aircraft must complete their turn within 0.5NM of the Southern Aerodrome Boundary and track parallel to the 08/26 runways on the crosswind leg. For fixed-wing aircraft flying the standard (left-hand) circuit pattern, this is a turn of more than 90° which must be made at low level, typically below 200 feet agl, especially when commencing the take-off run from the displaced threshold on runway 18. Helicopters turn right from Runway 18.
Runway 36 aircraft must turn base remaining within the ATZ and track parallel to runways 08/26 to turn on to final approach at a range not greater than 0.5NM. For fixed-wing aircraft flying the standard (right-hand) circuit, the base-leg turn must be made abeam Burstow Park Farm allowing for the drift caused by the northerly wind. The turn from base-leg to final requires a turn of more than 90° which must be made at low level and results in a very short final approach leg. A series of green woodsheds exist right on the southern boundary of the ATZ which provide a good visual landmark. These must be kept to the south of the aircraft at all times. Helicopters fly a left-hand circuit to Runway 36.
When Runway 08/26 is in use helicopter pilots must ensure they remain north of the southern ATZ boundary, approximately mid-way between Axes Lane and Cross Oak Lane (marked by Picketts and Brownslade Farms on the LFA diagram). This particularly important at night when fewer ground features are visible.
The Redhill UK AIP entry contains operational information and details of the LFA. All aircraft must have a serviceable transponder with altitude reporting. Those aircraft that do not may apply for an exemption. Visiting aircraft will be deemed to have an exemption by virtue of obtaining PPR by telephone. The use of Runway 18/36 is restricted to transponder equipped aircraft only.
The Redhill operational information page of the aerodrome’s website contains details of the LFA, VRPs, information of arrival/departure tracks, circuit and noise abatement procedures.
Terminal Control & Gatwick Approach
Gatwick Approach are required to provide a minimum separation of 3NM laterally or 3000FT vertically between IFR aircraft and any unknown aircraft within the CTA/CTR. A deviation outside of the ATZ or LFA may result in an infringement of the Gatwick controlled airspace. Any infringement may have an immediate impact on the approach controller’s workload and may require avoiding action or suspension of Gatwick movements. As the controller will not know the intentions of the unknown aircraft, they are required to take proactive action promptly. A telephone call to Redhill ATC highlighting the issue, ascertaining the aircraft identification and allowing Redhill sufficient time to contact the aircraft, issuing information or instructions to the infringing aircraft, if known, and for the pilot to comply with those instructions, all takes time. In the meantime, the risk remains while the aircraft remains within the CTA/CTR, distracting the controller who may need to issue instructions to multiple commercial aircraft operating to or from Gatwick until the risk no longer exists.
Some of the Gatwick departures route directly over Redhill Aerodrome, hence there is sometimes very little time to resolve conflict, especially when Runway 08 is in use at Gatwick.
Away from the Redhill area an additional ‘hot‐spot’ is traffic routeing via Bough Beech Reservoir which is underneath the eastern Gatwick CTA boundary. These are caused by aircraft climbing too early after departure or descending too late when arriving. When heading eastbound, do not commence a climb above 1,400 feet QNH until Bough Beech Reservoir is behind you. In the same manner, when heading westbound into Redhill, ensure you are at or below 1,400 feet QNH prior to reaching the eastern edge of the reservoir; plan your descent to be at or below 1,400 feet prior to that point.
Any infringement of the CTA in this area can have an immediate impact on traffic being sequenced by the Gatwick approach controller for Runway 26 or affect departures from Runway 08.
Redhill SSR Code
Redhill uses an unvalidated and unverified conspicuity code 3767 which pilots must only select when instructed to do so by Redhill ATC. As ATC only provides a service within 10NM of the Aerodrome, pilots flying outside this area should inform ATC on passing 10NM (i.e. just to the West of Bough Beech Reservoir) when they will be instructed to select A7000/2000. Pilots are encouraged to either obtain a service from Farnborough LARS East on Channel 123.225 or select the Frequency Monitor Code (FMC) 7012 and monitor Gatwick on Channel 126.825.
Prevent an airspace infringement
The Airspace & Safety Initiative website provides extensive advice on how to avoid the risk of infringing airspace. Redhill pilots are strongly encouraged to:
- Use a Moving Map which will provide a profile along your planned route showing the controlled airspace boundary.
- Take 2. When flying in proximity to Gatwick controlled airspace, and if able to, Take 2. Apply TEM when planning your route and altitude; there is high terrain to the northeast of Edenbridge with a spot height of 820 feet amsl. Use the Redhill-to-Tonbridge railway line to remain clear of the Gatwick CTR and in the area of lower terrain. There is half a mile between the railway line and the CTR boundary, hence it is prudent to apply the “line feature on the left” recommendation.
- Obtain a service Obtain a service from Farnborough ATSU on LARS East (Channel 123.225) or West (125.250MHz) as appropriate.
- Use a Frequency Monitor Code (FMC). Rather than squawking 7000/2000, if you do not want to obtain a service from ATC, use a FMC appropriate to the direction of flight. FMCs have proven to prevent infringements and reduce the severity of such occurrences.
Gatwick: Channel 126.825 Code: 7012
Once outside the area defined in the UK AIP EGKK AD 2.22 FLIGHT PROCEDURES (section 5) and in the chart at UK AIP ENR 6-80 (FREQUENCY MONITORING CODE (FMC) AREAS) use one of the following:
Farnborough West: 125.250MHz Code: 4572
Thames: 132.700MHz Code: 0012
- Use the correct QNH Obtain the Redhill QNH from the ATIS channel 125.305 which operates H24. If you are unable to receive the Redhill ATIS use the Gatwick QNH from their ATIS frequency 136.525MHz.
- Make a Detailed Plan. Build in your climb and descent points when planning your route. Know what VRPs look like and what airspace lies above them or close by. Note that most of the Redhill VRPs need to be overflown not above 1,400 feet QNH.
- Use the Redhill-to-Tonbridge railway line to remain clear of the Gatwick CTR. There is half a mile between the railway line and the CTR boundary, hence it is prudent to apply the “line feature on the left” recommendation.
- If appropriate – request a clearance. If for any reason a climb is required above the base of the CTA, then a clearance must be obtained from Gatwick Director on channel 126.825. If in any doubt, contact Gatwick Director for assistance.
The full set of hot-spot narratives can be found on this page: Local area information