# NTSB LAX97TA289: Bell UH-1H, N205DF, Tahoe City, CA, August 15, 1997 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Final report - Date: August 15, 1997, 10:38 local (17:38 UTC) - Place: Tahoe City, CA - Coordinates: 39.179817, -120.140281 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.1798&lon=-120.1403&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor, 6 uninjured - Status: Completed, report April 10, 1998 - Report: Approved by Office Director - NTSB case key (mKey): 29914 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX97TA289 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/29914/pdf - Page: https://openairdocs.org/ntsb/LAX97TA289 ## Probable cause The pilot's decision to attempt a takeoff in environmental conditions which exceeded the helicopter's performance capability, and his improper use of the collective, which caused a decay of the main rotor rpm, the collision with the lake, and the subsequent rollover. Factors in the accident were the high density altitude and the confined area. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of control - in flight, takeoff - initial climb - terrain condition - congested/confined area (contributing factor) - weather condition - high density altitude (contributing factor) - in-flight planning/decision - inadequate, pilot in command (cause) - aircraft performance,climb capability - exceeded - collective - improper use of, pilot in command (cause) - rotor rpm - not maintained, pilot in command (cause) - In flight collision with terrain/water, descent - uncontrolled - terrain condition - water - Roll over, other - collective - improper use of, pilot in command (cause) ## Analysis 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. ## Factual narrative On August 15, 1997, at 1038 hours Pacific daylight time, a Bell UH-1H helicopter, N205DF, crashed into Lake Watson near Tahoe City, California, and sank. The helicopter was operated by the Nevada Division of Forestry (NDF) as a public-use aircraft and was transporting fire fighting personnel to a nearby forest fire. The helicopter sustained substantial damage. The pilot and five of the six firefighters were not injured; however, one firefighter sustained minor injuries. Visual meteorological conditions prevailed at the time and a company flight plan was filed. The flight originated at the Minden, Nevada, airport at 1011 on the morning of the accident on a mutual aid fire response mission for the U.S. Forest Service in the Lake Tahoe basin. According to the pilot's written and verbal statement, he reported for work that morning and calculated the allowable load for the hottest time of the day and determined when one Helitack crew members would have to be bumped. After receiving the dispatch for the fire mission, the pilot flew to Lake Watson and circled the fire incident site several times, attempting to establish communications with the ground crew on scene. While circling the site the pilot determined that the area, "appeared large enough to land and that the obstructions were fifty-foot tall trees." The helicopter made an approach over the lake and landed on the beach where they were informed that they were no longer needed. The pilot reported to the NDF that as he lifted off from the camp site at the edge of the lake, he ran out of blade pitch and available power as he tried to climb above some trees, so he tried to reverse direction. At the middle of the turn the aircraft began descending rapidly toward the water, so 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 and broke the chin bubbles. The pilot stated, "at this point, we are upright on the water, rpm is still drooped, and the aircraft is beginning to turn slowly to the right." The pilot said that he reduced collective to recover 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 provided to the Safety Board by the NDF show that the helicopter was approximately 800 pounds over the hover out of ground effect ceiling for the existing temperature and pressure altitude. The temperature was reported as 68 degrees Fahrenheit and the elevation at the accident site was listed as 7,800 feet mean sea level. The density altitude was computed to be approximately 9,500 feet. (All referenced charts and documents are attached to the report). A review of the helicopter documents and registration data on file with the FAA Aircraft Registry revealed that the helicopter was a military surplus unit and not certificated in any category. ## Aircraft - Registration: [N205DF](https://openairdocs.org/deregistered/N205DF-2000-03-07), registration cancelled 2000-03-07, S/N 64-13770 (OpenAirDocs) - Reported make and model: Bell UH-1H - Registry model: [Bell UH-1H](https://openairdocs.org/model/bell-uh-1h) (registry code 1181407) (OpenAirDocs) - Category: Helicopter - Serial number: 64-13370 - Airframe hours: 5973 - Engines: Detr. Diesel T53L-13B 1100 horsepower turbo shaft - Damage: Substantial damage - Flight: Public aircraft, Part 91 - Operator: Usda / Forest Service - Registered owner: Nevada Division Of Forestry - Last inspection: AAIP, June 16, 1997, 60 hours before - Departed: MEV, MINDEN, NV - Destination: NV - Flight plan: Company VFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 48; flight instructor, airline transport, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: right; toxicology performed; flight hours: 10,500 total, 1,226 in this make and model, 9,280 as pilot in command, 64 in the last 90 days, 40 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Visibility: 30 statute miles - Lowest ceiling: none - Temperature: 68 °F, dew point 46 °F - Altimeter: 30.00 inHg ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 19970815022639A](https://openairdocs.org/incident/19970815022639A), Aug 15, 1997: Bell UH1H, Cedar Flat, CA, Substantial damage. Forestry helicopter was responding to a fire when it crashed into lake. From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.