# NTSB DEN03LA020: Aerospatiale AS-350BA, N20840, Monticello, UT, December 2, 2002 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: December 2, 2002, 11:25 local (18:25 UTC) - Place: Monticello, UT - Coordinates: 37.937221, -109.327774 - Nearby events: https://openairdocs.org/map.md?lat=37.9372&lon=-109.3278&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report March 2, 2004 - Report: Approved by Office Director - Parties: FAA FSDO - NTSB case key (mKey): 56146 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN03LA020 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/56146/pdf - Page: https://openairdocs.org/ntsb/DEN03LA020 ## Probable cause the pilot's failure to maintain rotor rpm. A related factor was the presence of an object in the path during the touchdown. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of control - in flight, approach - rotor rpm - not maintained, pilot in command (cause) - Forced landing, emergency descent/landing - autorotation - attempted, pilot in command - Roll over, descent - uncontrolled - object - other (contributing factor) ## Analysis According to the pilot, he had moved approximately 80 bags of seismic sensor cable earlier that morning with no problems. At approximately 1120, the pilot stopped operations to change lines. He proceeded to pick up five bags and was en route to the drop off point. During the approach to the north, the pilot "noticed that the Nr (rotor rpm) was high at roughly 400 rpm as [he] turned to the west." As the pilot slowed down, he added collective to reduce the rotor speed. The rotor rpm began to slow, at which point the pilot lowered the collective and applied forward cyclic to maintain forward airspeed. The rotor speed continued to decrease and the "low rotor speed warning horn" sounded. The pilot lowered the collective and flared, at which point the bags contacted the ground. The pilot then "noticed that the Nr was low" at approximately 320 rpm. The pilot "zeroed the airspeed, pumped the collective once[,] trying to slow the rate of decent and pulled up on the collective," just before impacting the ground. The helicopter settled onto the load beneath it, and subsequently rolled over on its right side causing substantial damage. An examination of the helicopter revealed no anomalies. ## Factual narrative On December 2, 2002, at approximately 1125 mountain standard time, an Aerospatiale AS-350BA, N20840, operated by Crew Concepts Inc., was substantially damaged following an autorotation and subsequent landing rollover 1 mile east of Monticello, Utah. The commercial pilot, the sole occupant on board, received minor injuries. The external load operation was being conducted under the provisions of Title 14 CFR Part 133. Visual meteorological conditions prevailed and no flight plan had been filed for the local geophysical flight that originated approximately 5 minutes prior to the accident. According to the pilot, he had moved approximately 80 bags earlier that morning with no problems. The bags contained seismic sensor cables. At approximately 1120, the pilot stopped operations to change lines. He proceeded to pick up five bags and was en route to the drop off point. During the approach to the north, the pilot "noticed that the Nr [rotor rpm] was high at roughly 400 rpm as [he] turned to the west." As the forward speed slowed down, the pilot added collective to reduce the rotor speed. The rotor rpm began to slow but continued to decrease, at which point the pilot lowered the collective and applied forward cyclic to maintain forward airspeed. The rotor speed continued to decrease and the "low rotor speed warning horn" sounded. The pilot lowered the collective and flared, at which point the bags contacted the ground. The pilot then "noticed that the Nr was low" at approximately 320 rpm. Impact with the ground was unavoidable and the pilot "zeroed the airspeed, pumped the collective once[,] trying to slow the rate of decent and pulled up on the collective," just before impacting the ground. The helicopter settled onto the load on the ground. Subsequently, the helicopter rolled over, coming to rest on its right side. The tail boom was severed, the engine and transmission were separated, and the main rotor blades and hub assembly were destroyed. On March 6, 2003, the fuel control unit was examined at Turbomeca, Grand Prairie, Texas. No anomalies were reported. An examination of the helicopter's systems revealed no anomalies. The calculated density altitude at the accident site was 7,443 feet. The helicopter's maximum substantiated pressure altitude is 16,000 feet. ## Aircraft - Registration: [N20840](https://openairdocs.org/deregistered/N20840-2005-06-22), registration cancelled 2005-06-22, S/N 1070, built 1979 (OpenAirDocs) - Reported make and model: Aerospatiale AS-350BA - Registry model: [Aerospatiale AS350BA](https://openairdocs.org/model/aerospatiale-as350ba) (registry code 8680817) (OpenAirDocs) - Registry engine: [Turbomeca ARRIEL-1SER](https://openairdocs.org/engine/turbomeca-arriel-1ser) (registry code 60030, turbo-shaft) (OpenAirDocs) - Category: Helicopter - Serial number: 1070 - Engines: Turbomeca Aerial 1B 681 horsepower turbo shaft - Damage: Substantial damage - Flight: Other work use, Part 133 - Operator: Crew Concepts Inc - Registered owner: Copter Lease LLC Trustee - Airworthiness certificate: Standard, Normal - Departed: NONE, Monticello, UT ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 41; injuries: minor; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--w/ waivers/lim; last flight review March 22, 2002; seat: right; flight hours: 6,790 total, 815 in this make and model, 6,590 as pilot in command, 59 in the last 90 days, 52 in the last 30 days, 6 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 130° at 4 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 46 °F, dew point 28 °F - Altimeter: 30.19 inHg - Observed at: BDG, 24 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 20021202031869A](https://openairdocs.org/incident/20021202031869A), Dec 2, 2002: Snias AS350BA, Monticello, UT, Substantial damage. (-23) Pilot was executing a shallow approach to an open field to drop off a 50 foot long class b external load. On short final pilot noticed rotor RPM increase… 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.