Date:	Friday 7 June 1957
Time:	09:45
Type:	Hawker Hunter F Mk 5
Owner/operator:	41 Sqn RAF
Registration:	WN969
MSN:	S4/U/2956
Fatalities:	Fatalities: 0 / Occupants: 1
Aircraft damage:	Destroyed
Location:	Downe, 2 miles east of RAF Biggin Hill, Bromley, Kent, England -   United Kingdom
Phase:	Initial climb
Nature:	Military
Departure airport:	RAF Biggin Hill, Bromley, Kent
Destination airport:
Confidence Rating:	Information is only available from news, social media or unofficial sources

Narrative:
Hawker Hunter F.Mk.5 WN696: Delivered to the RAF at 5 MU RAF Kemble 11th May 1955. Sole operational service career was as "N" of 41 Squadron, RAF Biggin Hill

Soon after take-off from Biggin Hill on the morning of 7th June 1957, an accident occurred to Hawker Hunter Mk.5 WN969. The pilot had been detailed to lead a formation of four aircraft on a high level practice interception - he throttled back at 2000ft, reducing his engine speed from 8,400 rpm to 8,000rpm, then down to 7,800rpm. At that instant the pilot heard a muffled explosion, noted a rapid loss of rpm, and was informed by a startled No.2 that flames about 30 ft in length were issuing from his jet pipe. The pilot immediately thought something along the lines of "bugger this for a game of soldiers" and closed the throttle completely, jettisoned the hood and then ejected. WN969 flew on for a short distance before striking the ground in a 45-degree bank to starboard.

Extensive digging operations were necessary to disinter the remains of the engine, which were recovered from a depth of about 10ft. The engine was taken to Biggin Hill for examination - when, after some considerable difficulty, the exhaust cone and tail pipe were removed from the rear of the turbine shroud, the damage suffered by the High Pressure turbine blades and low pressure nozzle guide vanes appeared to be due to severe over-fuelling. The evidence seemed to point to a sticking fuel distribution valve, and the engine was at once despatched to the manufacturer for a more detailed examination.

Strip examination was carried out under A.I.B. supervision. About one third of the circumference of the turbines and nozzle guide vanes had been submerged in molten aluminium in the ground fire - this had solidified, locking both turbines and nozzle guide vanes together. This had to be melted out before the turbine assembly could be stripped. The combustion chamber was cut open and about 18 inches of the inner locating shroud was found to be separated at the last line of spot welds, and bent upwards. Metallurgical analysis confirmed that it had suffered fatigue failure at a spot weld location, split, and folded over a section of the primary nozzle guide vanes.

It was noted that this was the twelfth case of this type of combustion chamber failure since January 1956 - of these twelve, six resulted in severe turbine damage necessitating four forced landings and two ejections. This type of engine (used in both the Hunter and the Javelin) was already being modified to eliminate the spot welds at the rate of 20 per month

The pilot (Flying Officer C. W. G. Young, aged 24) ejected safely. The aircraft crashed into a field at Downe, 2 miles east of Biggin Hill, killing a horse and injuring two others on the ground.

1. Halley, James (1999) Broken Wings – Post-War Royal Air Force Accidents Tunbridge Wells: Air-Britain (Historians) Ltd. p.171 ISBN 0-85130-290-4.
2. Royal Air Force Aircraft WA100-WZ999 (James J Halley, Air Britain, 1983 p 65)
3. Category Five; A Catalogue of RAF Aircraft Losses 1954 to 2009 by Colin Cummings p.251
4. Birmingham Daily Post - Saturday 8 June 1957
5. National Archives (PRO Kew) File AVIA 5/37/S2880: https://discovery.nationalarchives.gov.uk/details/r/C6578660
6. http://web.archive.org/web/20170421194235/http://www.ejection-history.org.uk:80/PROJECT/YEAR_Pages/1957.htm#may
7. http://www.ukserials.com/results.php?serial=WN
8. http://sussexhistoryforum.co.uk/index.php?topic=4996.0
9. http://www.ukserials.com/losses-1957.htm
10. https://en.wikipedia.org/wiki/Downe

Date/time	Contributor	Updates
10-Jan-2009 11:55	ASN archive	Added
15-Mar-2012 23:52	Dr. John Smith	Updated [Cn, Operator, Total fatalities, Total occupants, Other fatalities, Location, Country, Phase, Departure airport, Source, Narrative]
16-Aug-2012 08:45	Nepa	Updated [Aircraft type, Operator, Location]
03-Jan-2019 15:23	Anon.	Updated [Time, Aircraft type, Narrative]
25-Jan-2020 23:33	Dr. John Smith	Updated [Location, Departure airport, Source, Narrative]
18-Jul-2020 21:16	Dr. John Smith	Updated [Time, Location, Source, Narrative]
05-Aug-2020 18:47	Dr. John Smith	Updated [Narrative]
07-Dec-2020 00:33	Dr. John Smith	Updated [Source]
26-Jun-2023 21:18	Nepa	Updated [[Source]]