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ASN Wikibase Occurrence # 31053
Last updated: 24 November 2020
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Date:15-AUG-1997
Time:10:38 PDT
Type:Silhouette image of generic UH1 model; specific model in this crash may look slightly different
Bell UH-1H
Owner/operator:Nevada SDF
Registration: N205DF
C/n / msn: 4477
Fatalities:Fatalities: 0 / Occupants: 7
Other fatalities:0
Aircraft damage: Written off (damaged beyond repair)
Category:Accident
Location:Lake Tahoe, Californa -   United States of America
Phase: Manoeuvring (airshow, firefighting, ag.ops.)
Nature:Fire fighting
Departure airport:Tahoe City, CA
Destination airport:Sierra Nevada Mountains, CA
Investigating agency: NTSB
Narrative:
The public-use helicopter was transporting fire fighting personnel to a nearby forest fire at a small lake in the Sierra Nevada Mountains. The pilot said he calculated the allowable load for the hottest time of the day when he reported for work that morning.

After dispatch for the fire mission, the pilot flew to the small lake where he determined that the area, 'appeared large enough to land and that the obstructions were fifty-foot tall trees.' He made an approach over the lake and landed on the beach and was told that they were no longer needed. The pilot said that as he lifted off from the lake edge he ran out of blade pitch and available power as he tried to climb above the trees and was forced to reverse direction. At the middle of the turn the aircraft began descending rapidly toward the water, and he attempted to accelerate the aircraft and pulled power until the rotor rpm began to droop.

The helicopter settled into the lake with about 10 knots of forward airspeed. The pilot said the helicopter remained upright on the water with the skids immersed and a dropped main rotor rpm. The pilot reduced collective and recovered rpm with the intention of hovering the helicopter back to the beach area.

After the rpm returned to normal, he increased collective, and the helicopter rolled to the right and sank inverted. Review of the cargo manifest, load calculation sheet, and hover ceiling chart show that the helicopter was about 800 pounds over the hover out of ground effect ceiling for the temperature and pressure altitude. The density altitude was computed to be approximately 9,500 feet.

Sources:

http://dms.ntsb.gov/aviation/AccidentReports/qojewp45iwqcqm45uerkemix1/R10312011120000.pdf


Revision history:

Date/timeContributorUpdates
27-Sep-2008 01:00 ASN archive Added
31-Oct-2011 11:52 Dr. John Smith Updated [Time, Total fatalities, Total occupants, Other fatalities, Location, Country, Phase, Nature, Departure airport, Destination airport, Source, Damage, Narrative]

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