Date:	Thursday 19 August 1948
Time:	day
Type:	Sikorsky R-4 Hoverfly I
Owner/operator:	RAE Farnborough
Registration:	KL109
MSN:
Fatalities:	Fatalities: 0 / Occupants: 2
Aircraft damage:	Destroyed
Location:	Buckland, 4 miles North East of Farringdon, Berkshire -   United Kingdom
Phase:	En route
Nature:	Military
Departure airport:	RAF Brize Norton, Carterton, Oxfordshire
Destination airport:

Narrative:
Sikorsky R-4 Hoverfly I KL109, RAE Farnborough: Written off (damaged beyond repair) when crashed 19-8-48 at Buckland, 4 miles North East of Farringdon, Berkshire.

The helicopter was being used as a camera platform, to film the dropping of a universal freight container from a Handley Page Halifax C.8 of the ATDU (Air Transport Development Unit). Whilst flying at 500 feet toward RAF Brize Norton, the helicopter lurched suddenly onto its side, and descended rapidly out of control

The helicopter struck a substantial hedge during its impact with the ground, which acted as a "cushion" and probably saved the two crew from death or serious injury:

Crew of Hoverfly KL109:
Flight Lieutenant J N Dennis, RN (pilot)
Mr. A Bishop, RAE Farnborough (Civilian Flight test Observer)

The cause of the accident was a failure to wire-lock a bolt attaching one of the rotor blades to its friction damper. The allowed the rotor blade to flap about laterally, leading to a complete and immediate loss of lift from the rotor.

The crash location of Buckland is a village and large civil parish about 4 miles northeast of Farringdon in the Vale of White Horse District. Buckland was part of Berkshire until the 1974 boundary changes transferred it to Oxfordshire.

1. Halley, James (1999). Broken Wings – Post-War Royal Air Force Accidents. Tunbridge Wells: Air-Britain (Historians) Ltd. ISBN 0-85130-290-4.
2. Final Landings: A Summary of RAF Aircraft and Combat Losses 1946 to 1949 by Colin Cummings p.419
3. https://en.wikipedia.org/wiki/Sikorsky_R-4
4. RAE Farnborough: Hoverfly Mk 1: directional behaviour (RAE Rep AERO 2268): National Archives (PRO Kew) File DSIR 23/17538: https://discovery.nationalarchives.gov.uk/details/r/C2431757
5. https://en.wikipedia.org/wiki/Buckland,_Oxfordshire

Date/time	Contributor	Updates
17-Apr-2023 18:27	Dr. John Smith	Added