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Date: | Saturday 21 February 1959 |
Time: | day |
Type: | Bristol 171 Sycamore HR Mk 14 |
Owner/operator: | 194 Sqn RAF |
Registration: | XE319 |
MSN: | 13221 |
Fatalities: | Fatalities: 2 / Occupants: 2 |
Aircraft damage: | Destroyed |
Location: | 6 miles South of RAF Kuala Lumpur -
Malaysia
|
Phase: | Initial climb |
Nature: | Military |
Departure airport: | RAF Kuala Lumpur, Malaya |
Destination airport: | |
Confidence Rating: | Information is only available from news, social media or unofficial sources |
Narrative:Bristol 171 Sycamore HR14 XE319, 194 Squadron, RAF - Written off 21/02/1959: Spun into the ground from 400 feet killing two crew six moles south of RAF Kuala Lumpur, Malaya, after one of the rotor blades detached in flight. Aircraft caught fire on impact, and the two crew members were killed.
This accident led to the grounding of the Sycamore fleet while work was done to investigate the main rotor failure causes. Under the extreme hot and humid climatic conditions, it was found that the wooden blades deteriorated due to moisture absorption, which caused swelling and consequent decay of the (already not very brilliant) helicopter’s performance.
Dynamic imbalance of the main rotor was another common problem which seriously affected the first generation of helicopter rotor blades like those of the Bristol 171.
However the most serious problem was another: with the humidity the glue joints started to fail and this led to the deposit of moisture in the internal structure of the blades and consequently dry rot. The problem was only partially overcome when blade-spar and external glued joints were sealed as suggested by the technicians to prevent the internal deposit of moisture. Initially heavy mass-balance weights were added to the blade tips to correctly reposition the centre of gravity. This improved the dynamic balancing and reduced vibrations. Finally the aircraft resumed normal duties in February 1960.
Sources:
1. Halley, James (1999) Broken Wings – Post-War Royal Air Force Accidents Tunbridge Wells: Air-Britain (Historians) Ltd. p.199 ISBN 0-85130-290-4.
2. Royal Air Force Aircraft XA100-XZ999 (James J Halley, Air Britain, 2001 p 22)
3. Malaya 1948-1960 – Emergency!! Never, Just a Forgotten War By Joe P. Plant
4. National Archives (PRO Kew) File BT233/2408:
https://discovery.nationalarchives.gov.uk/details/r/C424529 5.
http://www.ukserials.com/results.php?serial=XE 6.
https://www.helis.com/database/cn/42080/ 7.
http://www.filton.flyer.co.uk/bristol/prod171.html 8.
http://www.ukserials.com/losses-1959.htm 9.
https://www.heli-archive.ch/en/helicopters/in-depth-articles/bristol-171-sycamore/ Revision history:
Date/time | Contributor | Updates |
21-Apr-2013 20:13 |
Dr. John Smith |
Added |
22-Apr-2013 08:34 |
Nepa |
Updated [Operator, Location] |
27-Jan-2020 16:16 |
Dr. John Smith |
Updated [Time, Operator, Location, Source, Narrative] |
27-Jan-2020 22:36 |
stehlik49 |
Updated [Aircraft type, Operator, Operator] |