Date:	Thursday 20 December 1951
Time:	night
Type:	Avro Lincoln B Mk 2
Owner/operator:	Radar Reconnaissance Flt RAF
Registration:	SX991
MSN:	OT-C
Fatalities:	Fatalities: 0 / Occupants: 6
Aircraft damage:	Destroyed
Location:	Coates Farm, Watlington, 4 mi E of RAF Benson, Oxfordshire, England -   United Kingdom
Phase:	Approach
Nature:	Military
Departure airport:	RAF Benson, Oxfordshire
Destination airport:	RAF Benson, Oxfordshire
Confidence Rating:	Information is only available from news, social media or unofficial sources

Narrative:
Avro Lincoln SX991/C: Written off (damaged beyond repair) 20/12/1951: Following an uneventful aerial photography and surveillance mission, the crew was returning to their base at Benson, south Oxfordshire. On final approach by night, the pilot-in-command completed two successive turns to the left and then to the right, when the aircraft hit the ground and crashed in a field at Coates Farm, Coates Lane, Watlington, Oxfordshire, located about 4 miles east of the airfield. The airplane was damaged beyond repair and all six crew members were unhurt.

In October 1951 two 58 Sqn Lincoln’s, SX991/‘OT:C’ and RF331/‘OT:B’, based at RAF Benson in Oxfordshire were formed into the new Radar Reconnaissance Flight (RRF) to exploit the potential of H2S radar for reconnaissance purposes. With the imminent arrival of the V Bomber Force, who planned to operate from high-level using the aircraft's radar to navigate and identify their targets, it was essential that radar signatures of likely routes and even targets were assembled into a target information library. Consequently, the RRF aircraft were tasked to fly sorties into various areas of mainland Europe, particularly Germany. As the H2S radar scanned the ground, identifying prominent features, these details were photographed. These photographs were then used to provide V Bomber crews with a clear indication of the likely radar signature of prominent features on their intended routes towards their actual targets.

Exact details of the RRF’s activities have never been released. One particular ‘special duty’ sortie, flown by Sgt Gill in SX991 on the night of 20 December 1951, was so sensitive that it was actually authorised by the then Prime Minister, Winston Churchill.

Probable cause: It was determined that the pilot-in-command did not have a sufficient experience with night missions and failed to consult his altimeters while approaching the airbase. In doing so, he did not realize that the aircraft lost altitude during the two last turns. It is also reported that the Blind Approach Beam System (BABS) was faulty, which was considered as a contributory factor.

1. Halley, James (1999) Broken Wings – Post-War Royal Air Force Accidents Tunbridge Wells: Air-Britain (Historians) Ltd. p.123 ISBN 0-85130-290-4.
2. Royal Air Force Aircraft SA000-VZ999 (James J Halley, Air Britain)
3. Last Take Off; A Catalogue of RAF Aircraft Losses 1950 to 1953 by Colin Cummings p.207
4. https://spyflight.co.uk/aircraft/#Avro
5. https://www.baaa-acro.com/crash/crash-avro-694-lincoln-b2-near-raf-benson
6. SX991 when with 58 Squadron RAF: https://www.worldwarphotos.info/gallery/uk/raf/lincoln/lincoln-sx991/
7. https://en.wikipedia.org/wiki/List_of_accidents_and_incidents_involving_the_Avro_Lincoln#1950s .

Date/time	Contributor	Updates
27-Sep-2008 01:00	ASN archive	Added
10-Mar-2013 20:36	Dr. John Smith	Updated [Operator, Location, Phase, Nature, Destination airport, Source, Damage, Narrative]
30-Apr-2013 21:55	Dr. John Smith	Updated [Aircraft type, Location, Source, Narrative]
06-May-2013 14:30	Nepa	Updated [Operator, Location]
17-Feb-2021 22:43	Dr. John Smith	Updated [Time, Operator, Location, Departure airport, Destination airport, Source, Narrative]
18-Feb-2021 08:45	King T.	Updated [Operator, Location, Operator]
18-Feb-2021 15:52	Dr. John Smith	Updated [Source, Narrative]
22-Jun-2021 19:35	Anon.	Updated [Aircraft type, Operator]
17-Jul-2023 07:44	Nepa	Updated [[Aircraft type, Operator]]