Fighter Interception Development Unit RAF
The Fighter Interception Unit (FIU) was a special fighter unit of the Royal Air Force during the Second World War. It was part of Air Defence of Great Britain
The Fighter Interception Unit was initially set up to counter increasing night raids by the Luftwaffe, and thus to evaluate technological advances such as airborne interception (radar) equipment and other proposed operational innovations.
The unit was formed at RAF Tangmere in April 1940 under the command of Squadron Leader George Philip (known as Peter) Chamberlain, with a strength of 5 Blenheims equipped with A.I.Mark III, the latest variant of Airborne Interception (A.I.) radar.
Operations initially consisted of daytime practice interceptions and operational night defence flights. The night fighter Blenheims were directed several times to possible targets, in the early days of Ground-controlled interception (GCI) it proved difficult to both acquire and then maintain a radar contact and successfully intercept.
However on the night of the 22/23 July 1940 a Blenheim Mk. IF flown by Flying Officer Ashfield, with a crew of Pilot Officer C. Morris (Observer) and Sergeant R.A. Leyland (AI Operator), patrolled the Sussex coast at 10,000 feet. They were directed to a possible intercept by the controller at Poling CH radar station who reported an incoming raid. Sgt. Leyland reported a response on the A.I. at a range of 8,000 feet and presently P/O Morris made a visual sighting of a Dornier Do 17 to port and below the Blenheim. Ashfield closed the distance to 400 feet and then opened fire. Strikes were observed on fuselage and engines, the Dornier lurched to starboard and fell away, 5 miles south of Bognor Regis. The aircraft, a Dornier 17Z of 2 Staffel, Kampfgeschwader 3, crashed into the sea, the first airborne radar intercepted kill in history.
The unit was also later equipped with the Hawker Hurricane and the Bristol Beaufighter while at RAF Tangmere[1]
Between 1940 and June 1944, some 21 victories were claimed by the FIU.
A FIU detachment was at RAF Newchurch to compliment the already formed 150 Wing with the Hawker Tempest V, where it tested the AN/APS 13 range-determining radar for night fighting use.[2] This special flight of Tempest V's were formed to develop counter measures to the V-1 Flying Bomb which had begun falling on South-East England. This flight operated mainly by night, and claimed 86 ½ V1's destroyed before being absorbed into No 501 Squadron. The FIU's Squadron Leader Joseph Berry claimed 52 V-1's to become the RAF's top scorer against the flying bombs.
On 23 August 1944 the FIU became the 'Fighter Interception Development Squadron' (FIDS). By the latter war years the main element of the unit had become the 'Night Fighter Development Wing' (NFDW) -comprising the Bomber Support Development Unit (BSDU), the FIDS, and the 'Fighter Experimental Flight' (FEF), the latter specialising in day 'Ranger' operations by Mosquitoes.
During the closing months of the war the BSDU claimed four victories, the FIDS two victories, and the FEF eight victories plus a large number of aircraft destroyed on the ground.
In late 1944 a radar-equipped Vickers Wellington was modified for use by the Fighter Interception Unit as one of the first Airborne Early Warning and Control aircraft. It operated at an altitude of 4,000 feet over the North Sea to control Mosquito night fighters intercepting Heinkel He 111s flying from Dutch airbases and carrying out airborne launches of the V-1 flying bomb.
Bases
- RAF Tangmere 18 April 1940 to 20 August 1940
- RAF Shoreham 20 August 1940 to 1 February 1941
- RAF Ford 1 February 1941 to 3 April 1944
- RAF Wittering 3 April 1944 to 23 August 1944 [3]