Filton Aerodrome
Encyclopedia
Bristol Filton Airport or Filton Aerodrome lies on the border between Filton
and Patchway
, within South Gloucestershire
, 4 NM north of Bristol
, England. The airfield is bounded by the A38
trunk road to the east, the former London to Avonmouth
railway line to the south and the Old Filton Bypass road to the north west. The aerodrome's main runway runs east–west. The aerodrome is also called Filton Airfield.
Bristol Filton Aerodrome has a CAA
Ordinary Licence (number P741) that allows flights for the public transport of passengers or for flying instruction as authorised by the licensee (BAE Systems (Aviation Services) Limited).
Companies within the boundary of the aerodrome are BAE Systems
(which own the aerodrome), Airbus
, MBDA
and Rolls-Royce
, as well as a number of aircraft maintenance companies, flying schools and the South West of England Royal Mail
letter sorting depot. It has passenger facilities for corporate flights.
Filton's runway is one of the widest (300 feet or 91 m) and is 8,094 feet or 2,467 m long, having been extended first for the maiden flight of the Bristol Brabazon
airliner in 1949 and again in the late 1960s for Concorde
.
The first flight of the Concorde 002 prototype took place on 9 April 1969 at Filton Aerodrome. All other British-built Concordes also used the main Filton runway for their first flights.
On 26 November 2003, Concorde 216 (G-BOAF) made the final ever Concorde flight from Heathrow, passing over the Bay of Biscay
before making a low pass over Bristol and finally returning to Filton where it is now maintained on a temporary apron as a visitor attraction. It is hoped it will be joined by all the aircraft in the Bristol Aero
collection at Kemble Airport, in a purpose built museum.
The length of the runway and its closed-to-passengers status made it an ideal dispersion site for the nation's airborne nuclear deterrent during the Cold War
. During the Cuban Missile Crisis
, a number of Vulcan Bombers
were stationed at the airfield, on short-notice stand-by.
The aerodrome is equipped with full radio telephony services (control tower), runway/taxiway illumination and Instrument Landing System
(ILS).
In 1915, with the expansion of the aircraft works during World War I, the aerodrome was moved down the hill to its current location. In that year the Royal Flying Corps
opened a base on the airfield, access being from Hayes Lane, which led from Gypsy Patch Lane to the hamlet of Charlton
. The early buildings at the base were wooden huts, but eventually more permanent structures were erected, including Barnwell Hall.
During World War I, RFC Filton was mainly used as an aircraft acceptance facility.
A flying school was also located on the northern side of the airfield. This eventually became part of the West Works of the Engine Division of the Bristol Aeroplane Company. The West Works site was cleared in the late 1980s to make way for a Post Office Sorting centre.
From 1929 the 501 (City of Bristol) Squadron was based at RAF Filton
. The squadron was equipped with Hawker Hurricane
s by 1939 and formed part of the British forces sent to France. Following a heavy German raid on the Bristol Aeroplane Company
in 1940, a squadron of Supermarine Spitfire
s were based at Filton.
Prior to World War II, there were only grass runways at Filton. The main concrete runway was installed in 1941.
Prior to D-Day
, US-manufactured aircraft were assembled at Filton Aerodrome, from assemblies imported via Avonmouth
docks. Filton became a major port-of-entry for US casualties after the D-Day landings in June 1944. Most of the casualties were taken to Frenchay Hospital
.
The main runway was greatly extended in the late 1940s for the Brabazon project. Charlton village was demolished and the pre-war Filton bypass was severed. In the early 1960s, a new bypass was constructed, roughly parallel to the old one, and this later became part of the M5 motorway
.
The huge three-bay Brabazon Hangar was built in the late 1940s under the direction of T. P. O'Sullivan
. At the time, the hangar doors and the railway level crossing for the aircraft were the largest in the world. After a worker was crushed and killed while taking a nap in one of the folds of the hangar doors, a siren was installed to warn employees when the doors were being operated.
In 1948, 501 Squadron was equipped with De Havilland Vampire
jets. These were a common sight in the skies around Filton in the early to mid-1950s. 501 was disbanded on 3 February 1957. As a protest, one of the pilots decided to fly his aircraft under the Clifton Suspension Bridge
, but he crashed into a hillside on the Leigh Woods
side of the Avon Gorge
, near Sea Mills, Bristol
, and was killed.
During the early 1950s, British Overseas Airways Corporation
(BOAC) flew their Lockheed Constellation
s and Boeing Stratocruisers into Filton to be serviced in the newly completed Brabazon Hangar, then the largest hangar in the world. Maintenance flights to Filton ceased when suitable hangars were completed at London Heathrow Airport.
In 1960, an RAF Vulcan bomber, approaching from the west, landed at Filton in heavy rain. The pilot braked, but started to aquaplane. He decided to abort the landing. Although he managed to take-off and eventually land successfully elsewhere, the jet blast from the aircraft's four Bristol Siddeley Olympus
201 engines severely damaged a filling station at the eastern end of the runway, sent cars spinning on the A38 trunk road and wrecked the boundary fence steel railings. Eye witnesses claimed that the aircraft barely cleared the engine test beds next to the Bristol to South Wales
railway embankment. Subsequently, the filling station was moved further north, to a safer location.
On 3 December 1962, Bristol Siddeley Engines were using Vulcan XA894 as a flying test bed for the Olympus
22R, which was designed specifically to power the ill-fated BAC TSR-2
bomber. On that particular day, the aircraft was positioned at Filton on an apron near the former RAF station, with the 22R discharging its exhaust into a de-tuner. The power was increased to maximum reheat. An LP turbine disc was ejected from the engine, rupturing two fuel tanks and starting a fire. A brand new fire truck positioned in front of the aircraft was quickly enveloped in flames. The fire took hold so quickly that there was little the fire crew could do. Both the aircraft and fire truck were destroyed. Fortunately, the test engineers managed to exit the aircraft so there were no significant casualties.
After the disbanding of 501 squadron, Bristol Siddeley Engine apprentices used Barnwell Hall for accommodation and Bristol University Air Squadron continued to use some of the RAF facilities. Nowadays, many of the RAF buildings are derelict or have been demolished. For many years a surplus Concorde, G-BBDG
was housed in one of the hangars and cannibalised for spares by British Airways
; following the decommissioning of Concorde, it was moved to the Brooklands Museum
and restored.
A further downhill extension to the main runway was made for the Concorde project in the late 1960s. There was also a shorter concrete runway at Filton with a roughly north-south orientation, which was sometimes used by a Dakota to ferry key BAC personnel to Fairford during Concorde development in the early 1970s. This has now been demolished for the Charlton Hayes housing development.
On 21 November 2006, a public inquiry meeting was held with South Gloucestershire Council to discuss the building of 2,200 homes on the north side of the airfield. Building has started and the first residents moved in October 2010. Both the police helicopter and the Great Western Air Ambulance are based at the airport.
On 14 April 2011, BAE Systems announced that the airfield is to close at the end of 2012 and were seeking to redevelop the site, an announcement which attracted local press attention and public debate involving various local groups. A local non-party-political pressure group called the "Save Filton Airfield" campaign was formed to oppose to the plans.
Both the police helicopter and the Great Western Air Ambulance are based at the airport. Despite the announcement to redevelop the airfield, on 6th September 2011, it was announced that the Great Western Air Ambulance is to remain at Filton after the airfield closure.
Filton
Filton is a town in South Gloucestershire, England, situated on the northern outskirts of the city of Bristol, about from the city centre. Filton lies in Bristol postcode areas BS7 and BS34. The town centres upon Filton Church, which dates back to the 12th century and is a grade II listed building...
and Patchway
Patchway
Patchway is a town in South Gloucestershire, England, situated northwest of central Bristol. The town is a housing overflow for Bristol being contiguous to Bristol's urban area, and is often regarded as a large outer suburb. Nearby are the other Bristol satellite towns of Filton and Bradley Stoke....
, within South Gloucestershire
South Gloucestershire
South Gloucestershire is a unitary district in the ceremonial county of Gloucestershire, in South West England.-History:The district was created in 1996, when the county of Avon was abolished, by the merger of former area of the districts of Kingswood and Northavon...
, 4 NM north of Bristol
Bristol
Bristol is a city, unitary authority area and ceremonial county in South West England, with an estimated population of 433,100 for the unitary authority in 2009, and a surrounding Larger Urban Zone with an estimated 1,070,000 residents in 2007...
, England. The airfield is bounded by the A38
A38 road
The A38, part of which is also known as the Devon Expressway, is a major A-class trunk road in England.The road runs from Bodmin in Cornwall to Mansfield in Nottinghamshire. It is long, making it one of the longest A-roads in England. It was formerly known as the Leeds — Exeter Trunk Road,...
trunk road to the east, the former London to Avonmouth
Avonmouth
Avonmouth is a port and suburb of Bristol, England, located on the Severn Estuary, at the mouth of the River Avon.The council ward of Avonmouth also includes Shirehampton and the western end of Lawrence Weston.- Geography :...
railway line to the south and the Old Filton Bypass road to the north west. The aerodrome's main runway runs east–west. The aerodrome is also called Filton Airfield.
Bristol Filton Aerodrome has a CAA
United Kingdom Civil Aviation Authority
The Civil Aviation Authority is the public corporation which oversees and regulates all aspects of aviation in the United Kingdom. The CAA head office is located in the CAA House on Kingsway in Holborn, London Borough of Camden...
Ordinary Licence (number P741) that allows flights for the public transport of passengers or for flying instruction as authorised by the licensee (BAE Systems (Aviation Services) Limited).
Companies within the boundary of the aerodrome are BAE Systems
BAE Systems
BAE Systems plc is a British multinational defence, security and aerospace company headquartered in London, United Kingdom, that has global interests, particularly in North America through its subsidiary BAE Systems Inc. BAE is among the world's largest military contractors; in 2009 it was the...
(which own the aerodrome), Airbus
Airbus
Airbus SAS is an aircraft manufacturing subsidiary of EADS, a European aerospace company. Based in Blagnac, France, surburb of Toulouse, and with significant activity across Europe, the company produces around half of the world's jet airliners....
, MBDA
MBDA
MBDA is a missile developer and manufacturer with operations in France, Britain, Germany, Italy, and the United States. It was formed by a merger of Aérospatiale-Matra Missiles , Finmeccanica and Matra BAe Dynamics in December 2001. In 2003 the company had 10,000 employees...
and Rolls-Royce
Rolls-Royce plc
Rolls-Royce Group plc is a global power systems company headquartered in the City of Westminster, London, United Kingdom. It is the world’s second-largest maker of aircraft engines , and also has major businesses in the marine propulsion and energy sectors. Through its defence-related activities...
, as well as a number of aircraft maintenance companies, flying schools and the South West of England Royal Mail
Royal Mail
Royal Mail is the government-owned postal service in the United Kingdom. Royal Mail Holdings plc owns Royal Mail Group Limited, which in turn operates the brands Royal Mail and Parcelforce Worldwide...
letter sorting depot. It has passenger facilities for corporate flights.
Filton's runway is one of the widest (300 feet or 91 m) and is 8,094 feet or 2,467 m long, having been extended first for the maiden flight of the Bristol Brabazon
Bristol Brabazon
The Bristol Type 167 Brabazon was a large propeller-driven airliner, designed by the Bristol Aeroplane Company to fly transatlantic routes from the United Kingdom to the United States. The prototype was delivered in 1949, only to prove a commercial failure when airlines felt the airliner was too...
airliner in 1949 and again in the late 1960s for Concorde
Concorde
Aérospatiale-BAC Concorde was a turbojet-powered supersonic passenger airliner, a supersonic transport . It was a product of an Anglo-French government treaty, combining the manufacturing efforts of Aérospatiale and the British Aircraft Corporation...
.
The first flight of the Concorde 002 prototype took place on 9 April 1969 at Filton Aerodrome. All other British-built Concordes also used the main Filton runway for their first flights.
On 26 November 2003, Concorde 216 (G-BOAF) made the final ever Concorde flight from Heathrow, passing over the Bay of Biscay
Bay of Biscay
The Bay of Biscay is a gulf of the northeast Atlantic Ocean located south of the Celtic Sea. It lies along the western coast of France from Brest south to the Spanish border, and the northern coast of Spain west to Cape Ortegal, and is named in English after the province of Biscay, in the Spanish...
before making a low pass over Bristol and finally returning to Filton where it is now maintained on a temporary apron as a visitor attraction. It is hoped it will be joined by all the aircraft in the Bristol Aero
Bristol Aeroplane Company
The Bristol Aeroplane Company, originally the British and Colonial Aeroplane Company, was both one of the first and one of the most important British aviation companies, designing and manufacturing both airframes and aero engines...
collection at Kemble Airport, in a purpose built museum.
The length of the runway and its closed-to-passengers status made it an ideal dispersion site for the nation's airborne nuclear deterrent during the Cold War
Cold War
The Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...
. During the Cuban Missile Crisis
Cuban Missile Crisis
The Cuban Missile Crisis was a confrontation among the Soviet Union, Cuba and the United States in October 1962, during the Cold War...
, a number of Vulcan Bombers
Avro Vulcan
The Avro Vulcan, sometimes referred to as the Hawker Siddeley Vulcan, was a jet-powered delta wing strategic bomber, operated by the Royal Air Force from 1956 until 1984. Aircraft manufacturer A V Roe & Co designed the Vulcan in response to Specification B.35/46. Of the three V bombers produced,...
were stationed at the airfield, on short-notice stand-by.
The aerodrome is equipped with full radio telephony services (control tower), runway/taxiway illumination and Instrument Landing System
Instrument Landing System
An instrument landing system is a ground-based instrument approach system that provides precision guidance to an aircraft approaching and landing on a runway, using a combination of radio signals and, in many cases, high-intensity lighting arrays to enable a safe landing during instrument...
(ILS).
History
Opened in 1910, the original 'flying ground' was located near Fairlawn Avenue, next to the Bristol and Colonial Aeroplane Company works, at the top of Filton Hill.In 1915, with the expansion of the aircraft works during World War I, the aerodrome was moved down the hill to its current location. In that year the Royal Flying Corps
Royal Flying Corps
The Royal Flying Corps was the over-land air arm of the British military during most of the First World War. During the early part of the war, the RFC's responsibilities were centred on support of the British Army, via artillery co-operation and photographic reconnaissance...
opened a base on the airfield, access being from Hayes Lane, which led from Gypsy Patch Lane to the hamlet of Charlton
Charlton, Bristol
Charlton was the name of a small village in Gloucestershire, England, demolished in the late 1940s. It was located between Filton and Cribbs Causeway immediately north of Bristol.-History:...
. The early buildings at the base were wooden huts, but eventually more permanent structures were erected, including Barnwell Hall.
During World War I, RFC Filton was mainly used as an aircraft acceptance facility.
A flying school was also located on the northern side of the airfield. This eventually became part of the West Works of the Engine Division of the Bristol Aeroplane Company. The West Works site was cleared in the late 1980s to make way for a Post Office Sorting centre.
From 1929 the 501 (City of Bristol) Squadron was based at RAF Filton
RAF Filton
RAF Filton was a World War II, Royal Air Force Sector Airfield situated at Filton Aerodrome about 5 miles north of the city centre of Bristol, England....
. The squadron was equipped with Hawker Hurricane
Hawker Hurricane
The Hawker Hurricane is a British single-seat fighter aircraft that was designed and predominantly built by Hawker Aircraft Ltd for the Royal Air Force...
s by 1939 and formed part of the British forces sent to France. Following a heavy German raid on the Bristol Aeroplane Company
Bristol Aeroplane Company
The Bristol Aeroplane Company, originally the British and Colonial Aeroplane Company, was both one of the first and one of the most important British aviation companies, designing and manufacturing both airframes and aero engines...
in 1940, a squadron of Supermarine Spitfire
Supermarine Spitfire
The Supermarine Spitfire is a British single-seat fighter aircraft that was used by the Royal Air Force and many other Allied countries throughout the Second World War. The Spitfire continued to be used as a front line fighter and in secondary roles into the 1950s...
s were based at Filton.
Prior to World War II, there were only grass runways at Filton. The main concrete runway was installed in 1941.
Prior to D-Day
D-Day
D-Day is a term often used in military parlance to denote the day on which a combat attack or operation is to be initiated. "D-Day" often represents a variable, designating the day upon which some significant event will occur or has occurred; see Military designation of days and hours for similar...
, US-manufactured aircraft were assembled at Filton Aerodrome, from assemblies imported via Avonmouth
Avonmouth
Avonmouth is a port and suburb of Bristol, England, located on the Severn Estuary, at the mouth of the River Avon.The council ward of Avonmouth also includes Shirehampton and the western end of Lawrence Weston.- Geography :...
docks. Filton became a major port-of-entry for US casualties after the D-Day landings in June 1944. Most of the casualties were taken to Frenchay Hospital
Frenchay Hospital
Frenchay Hospital is a large hospital situated in Frenchay, South Gloucestershire, on the outskirts of Bristol, England, part of the North Bristol NHS Trust....
.
The main runway was greatly extended in the late 1940s for the Brabazon project. Charlton village was demolished and the pre-war Filton bypass was severed. In the early 1960s, a new bypass was constructed, roughly parallel to the old one, and this later became part of the M5 motorway
M5 motorway
The M5 is a motorway in England. It runs from a junction with the M6 at West Bromwich near Birmingham to Exeter in Devon. Heading south-west, the M5 runs east of West Bromwich and west of Birmingham through Sandwell Valley...
.
The huge three-bay Brabazon Hangar was built in the late 1940s under the direction of T. P. O'Sullivan
Terence Patrick O'Sullivan
Terence Patrick O'Sullivan BSc, PhD, FICE, MSocCE , was a civil engineer. He specialised initially in steel and reinforced concrete structures. Later he founded a firm of consulting engineers, T. P...
. At the time, the hangar doors and the railway level crossing for the aircraft were the largest in the world. After a worker was crushed and killed while taking a nap in one of the folds of the hangar doors, a siren was installed to warn employees when the doors were being operated.
In 1948, 501 Squadron was equipped with De Havilland Vampire
De Havilland Vampire
The de Havilland DH.100 Vampire was a British jet-engine fighter commissioned by the Royal Air Force during the Second World War. Following the Gloster Meteor, it was the second jet fighter to enter service with the RAF. Although it arrived too late to see combat during the war, the Vampire served...
jets. These were a common sight in the skies around Filton in the early to mid-1950s. 501 was disbanded on 3 February 1957. As a protest, one of the pilots decided to fly his aircraft under the Clifton Suspension Bridge
Clifton Suspension Bridge
Brunel died in 1859, without seeing the completion of the bridge. Brunel's colleagues in the Institution of Civil Engineers felt that completion of the Bridge would be a fitting memorial, and started to raise new funds...
, but he crashed into a hillside on the Leigh Woods
Leigh Woods
Leigh Woods is a 2 square kilometre area of woodland on the south-west side of the Avon Gorge, opposite the English city of Bristol and north of the Ashton Court estate. It has been designated as a National Nature Reserve. Small mountain biking circuits are present in the woods and the area is a...
side of the Avon Gorge
Avon Gorge
The Avon Gorge is a 1.5-mile long gorge on the River Avon in Bristol, England. The gorge runs south to north through a limestone ridge west of Bristol city centre, and about 3 miles from the mouth of the river at Avonmouth. The gorge forms the boundary between the unitary authorities of...
, near Sea Mills, Bristol
Sea Mills, Bristol
Sea Mills is a suburb of the English port city of Bristol. It is situated some 3.5 miles north-west of the city centre, towards the seaward end of the Avon Gorge. Nearby suburbs are Shirehampton, Sneyd Park, Combe Dingle and Stoke Bishop...
, and was killed.
During the early 1950s, British Overseas Airways Corporation
British Overseas Airways Corporation
The British Overseas Airways Corporation was the British state airline from 1939 until 1946 and the long-haul British state airline from 1946 to 1974. The company started life with a merger between Imperial Airways Ltd. and British Airways Ltd...
(BOAC) flew their Lockheed Constellation
Lockheed Constellation
The Lockheed Constellation was a propeller-driven airliner powered by four 18-cylinder radial Wright R-3350 engines. It was built by Lockheed between 1943 and 1958 at its Burbank, California, USA, facility. A total of 856 aircraft were produced in numerous models, all distinguished by a...
s and Boeing Stratocruisers into Filton to be serviced in the newly completed Brabazon Hangar, then the largest hangar in the world. Maintenance flights to Filton ceased when suitable hangars were completed at London Heathrow Airport.
In 1960, an RAF Vulcan bomber, approaching from the west, landed at Filton in heavy rain. The pilot braked, but started to aquaplane. He decided to abort the landing. Although he managed to take-off and eventually land successfully elsewhere, the jet blast from the aircraft's four Bristol Siddeley Olympus
Rolls-Royce Olympus
The Rolls-Royce Olympus was one of the world's first two-spool axial-flow turbojet aircraft engines, originally developed and produced by Bristol Aero Engines. First running in 1950, its initial use was as the powerplant of the Avro Vulcan V Bomber...
201 engines severely damaged a filling station at the eastern end of the runway, sent cars spinning on the A38 trunk road and wrecked the boundary fence steel railings. Eye witnesses claimed that the aircraft barely cleared the engine test beds next to the Bristol to South Wales
South Wales
South Wales is an area of Wales bordered by England and the Bristol Channel to the east and south, and Mid Wales and West Wales to the north and west. The most densely populated region in the south-west of the United Kingdom, it is home to around 2.1 million people and includes the capital city of...
railway embankment. Subsequently, the filling station was moved further north, to a safer location.
On 3 December 1962, Bristol Siddeley Engines were using Vulcan XA894 as a flying test bed for the Olympus
Rolls-Royce Olympus
The Rolls-Royce Olympus was one of the world's first two-spool axial-flow turbojet aircraft engines, originally developed and produced by Bristol Aero Engines. First running in 1950, its initial use was as the powerplant of the Avro Vulcan V Bomber...
22R, which was designed specifically to power the ill-fated BAC TSR-2
BAC TSR-2
The British Aircraft Corporation TSR-2 was a cancelled Cold War strike and reconnaissance aircraft developed by the British Aircraft Corporation for the Royal Air Force in the late 1950s and early 1960s...
bomber. On that particular day, the aircraft was positioned at Filton on an apron near the former RAF station, with the 22R discharging its exhaust into a de-tuner. The power was increased to maximum reheat. An LP turbine disc was ejected from the engine, rupturing two fuel tanks and starting a fire. A brand new fire truck positioned in front of the aircraft was quickly enveloped in flames. The fire took hold so quickly that there was little the fire crew could do. Both the aircraft and fire truck were destroyed. Fortunately, the test engineers managed to exit the aircraft so there were no significant casualties.
After the disbanding of 501 squadron, Bristol Siddeley Engine apprentices used Barnwell Hall for accommodation and Bristol University Air Squadron continued to use some of the RAF facilities. Nowadays, many of the RAF buildings are derelict or have been demolished. For many years a surplus Concorde, G-BBDG
G-BBDG
G-BBDG was the third British production Concorde built for evaluation testing. Along with the French Concorde F-WTSB, the aircraft was used to enable sufficient testing to allow for the Concorde fleet to receive certification...
was housed in one of the hangars and cannibalised for spares by British Airways
British Airways
British Airways is the flag carrier airline of the United Kingdom, based in Waterside, near its main hub at London Heathrow Airport. British Airways is the largest airline in the UK based on fleet size, international flights and international destinations...
; following the decommissioning of Concorde, it was moved to the Brooklands Museum
Brooklands Museum
Brooklands Museum is an independent charitable trust, established in 1987, whose aim is to conserve, protect and interpret the unique heritage of the Brooklands site. It is located south of Weybridge, Surrey and was first opened regularly in 1991 on of the original 1907 motor-racing circuit...
and restored.
A further downhill extension to the main runway was made for the Concorde project in the late 1960s. There was also a shorter concrete runway at Filton with a roughly north-south orientation, which was sometimes used by a Dakota to ferry key BAC personnel to Fairford during Concorde development in the early 1970s. This has now been demolished for the Charlton Hayes housing development.
On 21 November 2006, a public inquiry meeting was held with South Gloucestershire Council to discuss the building of 2,200 homes on the north side of the airfield. Building has started and the first residents moved in October 2010. Both the police helicopter and the Great Western Air Ambulance are based at the airport.
On 14 April 2011, BAE Systems announced that the airfield is to close at the end of 2012 and were seeking to redevelop the site, an announcement which attracted local press attention and public debate involving various local groups. A local non-party-political pressure group called the "Save Filton Airfield" campaign was formed to oppose to the plans.
Both the police helicopter and the Great Western Air Ambulance are based at the airport. Despite the announcement to redevelop the airfield, on 6th September 2011, it was announced that the Great Western Air Ambulance is to remain at Filton after the airfield closure.