# NTSB DEN99LA160: Bell UH-1H, N4085L, Silverton, CO, September 6, 1999 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: September 6, 1999, 08:30 local (14:30 UTC) - Place: Silverton, CO - Coordinates: 37.819759, -107.640167 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=37.8198&lon=-107.6402&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report November 30, 2000 - Report: Approved by Office Director - NTSB case key (mKey): 47264 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN99LA160 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/47264/pdf - Page: https://openairdocs.org/ntsb/DEN99LA160 ## Probable cause The total loss of engine power for undetermined reasons. A factor was the lack of suitable terrain for a forced landing. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(total) - mech failure/malf, hover - out of ground effect - turboshaft engine - failure,total (cause) - turboshaft engine - undetermined (cause) - Forced landing, emergency descent/landing - autorotation - performed, pilot in command - On ground/water encounter with terrain/water, emergency descent/landing - terrain condition - none suitable (contributing factor) - terrain condition - mountainous/hilly - terrain condition - rough/uneven ## Analysis The pilot said this was his first trip of the morning, and he was transporting approximately 300 pounds of construction materials. He said that the load was on the ground and he was hovering while ground personnel disconnected the cargo net. He said that one of the ground team radioed him and reported that 'fire and smoke was coming from your tail pipe.' The pilot said that he noticed that the rotor rpm warning light was on, and the engine out lights and horns had been activated. He lowered the collective and autorotated to the ground, but the main rotors impacted terrain. The aircraft records indicate that the engine came from a civilian overhaul facility, and was installed in N4085L approximately 21 hours prior to the accident. The Colorado Department of Minerals and Mines reported the mine entrance elevation was 11,500 feet. The density altitude was calculated to be 13,000 feet. ## Factual narrative On September 6, 1999, at 0830 mountain daylight time, a Bell UH-1H helicopter, N4085L, was substantially damaged during impact with terrain following an autorotation near Silverton, Colorado. The commercial pilot, the sole occupant on board, received minor injuries. The helicopter was being operated by High Country Helicopters, Inc., of Montrose, Colorado, under Title 14 CFR Part 133. Visual meteorological conditions prevailed for the local long-line cargo flight which originated from a staging area approximately 20 minutes before the accident. No flight plan had been filed. The pilot reported that this was his first trip of the morning, and he was transporting approximately 300 pounds of construction materials which were to be used to close a mine entrance. He said that the load was on the ground and he was hovering while ground personnel were disconnecting the cargo net. He said that one of the ground team radioed him and reported that "fire and smoke was coming from your tail pipe." The pilot said that he noticed that the rotor rpm warning light was on, and the engine out lights and horns had been activated. He lowered the collective and autorotated to the ground, but the main rotors impacted terrain. The tail rotor and its associated gear boxe separated from the aircraft. The tail boom was bent and pushed forward into the transmission. Aircraft records indicated that the engine was overhauled by the U.S. Army 791 hours before the accident. The maintenance records further indicated that the engine came from a civilian overhaul facility and was installed in N4085L approximately 21 hours prior to the accident. The Colorado Department of Minerals and Mines reported the mine entrance elevation was 11,500 feet. The density altitude was calculated to be 13,000 feet. ## Aircraft - Registration: [N4085L](https://openairdocs.org/deregistered/N4085L-2020-08-21), registration cancelled 2020-08-21, S/N 68-15655, built 1968 (OpenAirDocs) - Reported make and model: Bell UH-1H - Registry model: [Bell UH-1H](https://openairdocs.org/model/bell-uh-1h) (registry code 1181407) (OpenAirDocs) - Registry engine: [Lycoming T53-L-13](https://openairdocs.org/engine/lycoming-t53-l-13) (registry code 41551, turbo-shaft) (OpenAirDocs) - Category: Helicopter - Serial number: 68-15655 - Airframe hours: 3854 - Engines: Lycoming T53-L-13 turbo shaft - Damage: Substantial damage - Flight: Other work use, Part 133 - Registered owner: High Country Helicopters, Inc. - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, October 12, 1999 - Departed: NONE ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 44; flight instructor, commercial, private; airplane ratings: single-engine land; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 10,500 total, 5,000 in this make and model, 11,000 as pilot in command, 16 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 130° at 8 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 61 °F, dew point 45 °F - Altimeter: 30.00 inHg - Observed at: MTJ, 40 nm away ## 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 19990906046569A](https://openairdocs.org/incident/19990906046569A), Sep 6, 1999: Bell UH1H, Silverton, CO, No damage. (-23) Pilot was transporting an external load on the first flight of the day when the ground crew reported fire and smoke coming out the tail pipe of the… ## Other investigations on N4085L (1) 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. - [NTSB GAA19CA344](https://openairdocs.org/ntsb/GAA19CA344), Jun 6, 2019: Bell UH 1H (N4085L), Bethel, AK, substantial damage. Probable cause: The pilot's improper fuel planning, which resulted in fuel exhaustion and a total loss of engine power, and his improper landing flare during a forced autorotation, which resulted in a hard landing.… 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.