Past…

Flying has been taking place on the site of Denham Aerodrome since almost the earliest days of aviation. For some years a historian has been publishing the aerodrome’s History – discover the people who have shaped our present.

Present…

Overview

Denham Aerodrome is located several miles north-west of Heathrow Airport and approximately 4nm from RAF Northolt.

An Air/Ground Communication Service is provided whereby radio operators provide information to pilots, for example the runway in use, the local pressure setting, traffic information, etc. The radio operators do not give instructions to pilots.

The aerodrome is used by General Aviation users - basically all civil flying except that carried out by airlines. It includes emergency services, pollution, pipeline, powerline, fishery protection and traffic patrols, medical flights carrying urgently needed human organs or transporting the sick and injured, civil search and rescue, air survey, agricultural aviation, business aviation, flying training and private flying.

Much of the flying at Denham is for training. Some people train for a Private Pilot’s Licence to use privately, but many pilots who start flying at Denham make their way onto the flight decks of airlines in due course.

Supporting the flying operations is a diversity of technical and engineering activities and training. The aerodrome is home not only to flying schools offering pilot training for aeroplanes and helicopters, but also to maintenance and engineering companies; aerial filming; 2370 (Denham) Squadron Air Training Corps; Biggles Restaurant, which stands in its own grounds on the south side; and the Crew Room café which is sited next to the wartime hangar on the north side and gives an excellent view of the aircraft. Find more information about Who’s Here.

International flights are common, and close contact is maintained with Border Force, the Police and Special Branch.

Airspace

Similar to other aerodromes, Denham has a circular area radius 2nm called an Aerodrome Traffic Zone (ATZ). An ATZ is airspace set aside for the safe operation of aircraft using an aerodrome. At Denham the maximum height is 750 feet above ground level due to the proximity of RAF Northolt. There is an avoid area that aircraft are required to contact RAF Northolt before entering. Aircraft under the control of RAF Northolt or Heathrow overfly the ATZ. And there are several helicopter landing sites inside the Denham ATZ including Harefield Hospital.

Heathrow Airport has a large area of controlled airspace around it called the London Control Zone (London CTR). Denham lies just inside the northern boundary of the London CTR (see diagram below).

Arriving, departing

Some aircraft arrive/depart Denham route from the east, south or west under air traffic control of RAF Northolt or NATS (Heathrow). However, most aircraft arrive and depart Denham to the north. VRPs at St Giles and Maple Cross ensure that arriving and departing aircraft are safely separated from each other.

The arrival and departure procedures are published in the official UK Aeronautical Information Publication and in several flight guides. A briefing is provided on the website and visiting pilots must confirm they have read it before flight. New resident pilots are required to fly a sortie with a resident flying instructor to ensure they are familiarised with the procedures and relevant landmarks.

Runways and circuit

The aerodrome's main runway 06/24 is aligned with the south-west prevailing wind. Aircraft must take off and land into wind so most often aircraft take off on Runway 24. However, when the wind dictates, aircraft take off on Runway 06, and there is also a grass runway oriented south-east/north-west which is used when necessary.

Runway 06/24 is equipped with lights and aids so it may be used by day and night.

Aircraft sometimes fly a rectangular path around an aerodrome called a circuit. This starts with the take-off, followed by the crosswind leg, downwind leg, base leg and then the final approach. Circuits are flown to the north of the aerodrome due to the proximity of RAF Northolt.

In an effort to avoid most noise sensitive areas the circuit at Denham is comparatively small. While many aircraft can safely fly this path there are factors that affect an aircraft's course and pilots that fly a larger circuit are generally not doing anything wrong.

Weather conditions can have a marked effect on the path an aircraft takes: on days with little wind, or high temperatures, aircraft climb performance is reduced and this may necessitate aircraft flying a larger circuit; and days with a strong crosswind will affect the ability of aircraft to accurately fly the circuit path. Variation will also occur due to aircraft performance, as faster aircraft may have to fly a larger circuit. And quite often aircraft will have to fly a larger circuit in order to maintain a safe lateral separation from other aircraft. Consequently, flight path routes are represented not as lines but as swathes showing.

Training, and further training

Circuit training is an important part of the syllabus for the private pilot's licence in both aeroplanes and helicopters, and continuation training. Helicopters also practice hovering and manoeuvring over the aerodrome.

Essential training includes engine failure practice. Aeroplane instructors simulate engine failure by reducing power and pilots swiftly lower the nose and turn towards a suitable site where a forced landing could take place; the throttle is then returned to a climb power setting and the aircraft climbs away.

Helicopter pilot training also includes engine failure practice. Should a single engined helicopter lose power or suffer complete engine failure pilots are taught to carry out a controlled procedure called auto-rotation.

Low level circuits become necessary when the cloud base determines that a normal height visual circuit cannot be flown. These are practised on good weather days in preparation for inclement weather.

When a student pilot completes their training course and exams and gains a Private Pilot's Licence, the licence has a rating attached. The rating lasts two years then it must be revalidated or renewed: the pilot may need to do refresher training before doing a check flight. If a pilot wants to fly more sophisticated aircraft, or fly under instrument flight rules, or do aerobatics, or gain a Commercial Pilot's Licence, etc, they have to do further training.

Aerobatics are only permitted by professional pilots with prior permission from the Aerodrome Operator. This may need to be arranged with RAF Northolt and Heathrow Airport. Banner towing flights, and flights by airships and balloons, are not frequent but they may be carried out by suitable pilots with prior permission of the Aerodrome Operator.

Aerodrome Consultative Committee

As noted above, compliance with the procedures is secondary to the primary goal of safe flight. But where investigation provides evidence of non-compliance without any overriding reason, an informal exchange with the pilot may suffice to encourage more consistent compliance in the future. Where a pilot shows a lack of understanding of the procedures, if appropriate they will be required to fly a sortie with a resident flying instructor to re-familiarise them with the procedures.

In 1970 the Aerodrome Operator and local authorities agreed to form a committee to act as a means of consultation in accordance with s.35 of the Civil Aviation Act 1982. Government guidelines state that the role of aerodrome consultative committees is to promote greater understanding both to the surrounding community about airport operations and to the airport operator about the impact of those airport operations.

Committees can facilitate constructive discussion while maintaining an overview of trends.