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ASN Wikibase Occurrence # 140545
Last updated: 5 June 2020
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Date:21-MAY-1992
Time:14:20
Type:Silhouette image of generic LAMA model; specific model in this crash may look slightly different
Aérospatiale SA 315B Lama
Owner/operator:Heli-Services (Hong Kong)
Registration: VR-HJE
C/n / msn: 2618
Fatalities:Fatalities: 1 / Occupants: 2
Other fatalities:0
Aircraft damage: Substantial
Location:nr Siu Lang Shui, Castle Peak -   Hong Kong
Phase: Take off
Nature:Cargo
Departure airport:
Destination airport:
Narrative:
The helicopter was operating under Visual Flight Rules with an underslung load in an isolated, hilly area outside controlled airspace.
The load, slung on an 18 m cable and chain, was a heavy (962 kg) piece of geotechnical drilling equipment. The helicopter lifted the load from a work site on the crest of a ridge (elevation 230 m above mean sea level) to transport it to another site on the slope of a hill seme 600 m to the northeast. However, after circling the area, the pilot, apparently unable to locate the drop-off site, returned to the crest of the ridge. He lowered the load onto the ground about 30 m f rcm the original pick-up point and landed alongside. The site agent approached the helicopter and, on receiving a hand signal from the pilot, boarded the helicopter with the
intention of guiding the pilot to the correct drop-off location. The helicopter lifted off with the load again and as soon as it set course towards the drop-off site the underslung load was dragged through a low bush adjacent to the lift-off point. The helicopter lost height, struck the downslope of the hillside and crashed into a small valley about 30 m below the crest of the ridge. The pilot was killed and the site agent was seriously injured. The helicopter was substantially damaged. There was no fire.
The helicopter was being operated very close to or slightly above the maximum total weight authorized and was transitioned from the hover position to forward flight in a downwind direction. During this manoeuvre the underslung load snagged on a bush and on breaking free was set in pendulum motion. This motion generated a varying centrifugal force on the cargo chain resulting in significant and drastic changes in the forces acting on the helicopter. These gave rise to control problems which caused the heavily loaded helicopter to go out of control and crash.

Sources:

http://ebook.lib.hku.hk/HKG/B35836982.pdf


Revision history:

Date/timeContributorUpdates
25-Dec-2011 13:18 harro Added

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