# NTSB SEA98LA024: Bell 206L, N206LT, Idaho Falls, ID, December 16, 1997 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: December 16, 1997, 14:15 local (21:15 UTC) - Place: Idaho Falls, ID - Coordinates: 43.429092, -111.889198 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=43.4291&lon=-111.8892&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report July 13, 1998 - Report: Approved by Office Director - NTSB case key (mKey): 42745 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA98LA024 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/42745/pdf - Page: https://openairdocs.org/ntsb/SEA98LA024 ## Probable cause loss of engine power for undetermined reason(s). A factor relating to the accident included a dirt berm/ridge in the field where the pilot executed the forced landing. ## Analysis About ten minutes after departing on a repositioning flight, the aircraft's engine experienced a total power loss. The pilot elected to autorotate to an open farm field, where the helicopter touched down on frozen muddy terrain. As the helicopter slid forward, it impacted a ridge of frozen dirt, resulting in the collapse of the skids. When the skids collapsed, the main rotor impacted the tail boom, and the aircraft sustained substantial damage. An inspection of the aircraft revealed no anomalies in any of its systems, and no contamination or water accumulation was found in its fuel. The reason for the loss of power was not determined. ## Factual narrative On December 16, 1997, approximately 1415 mountain standard time, a Bell 206L helicopter, N206LT, collided with the terrain during a forced landing about 15 miles south of Idaho Falls, Idaho. The airline transport pilot and his passenger were not injured, but the aircraft, which was owned by Tundra Copters, Inc., of Fairbanks, Alaska, and operated by Briles Helicopters, Inc., of Van Nuys, California, sustained substantial damage. The 14 CFR Part 91 repositioning flight, which was being conducted in visual meteorological conditions, departed Idaho Falls about ten minutes prior to the accident, and was en route to Salt Lake City International Heliport. No flight plan had been filed, and there was no report of an ELT activation. The pilot reported that the aircraft had been sitting on the ramp for a little over two months prior to the initiation of this flight. He said that during that time, the fuel tank was 17 gallons short of being full, but that it had been topped off prior to the flight. He reported that fuel had been drained from the aircraft prior to starting the engine, and that after finding no contamination or water accumulation, the aircraft was run on the ground for about 20 minutes. After the ground-run, the helicopter was hovered over the airport ramp for about five minutes prior to calling for departure. The pilot said that after departure he remained at a low altitude because he had overheard the pilot of another aircraft announce that he was inbound from the direction in which the helicopter pilot was departing. He said that about ten minutes after departure, while cruising at 5,500 feet MSL (760 feet AGL) and 100 knots indicated airspeed, the engine suddenly lost all power. The pilot elected to autorotate to a nearby open farm field, where the helicopter touched down on muddy terrain and slid forward until contacting a small ridge of frozen dirt. Upon impacting the ridge, the skids collapsed, and the main rotor blades contacted the tail boom. A Federal Aviation Administration Inspector from the Salt Lake City, Utah Flight Standards District Office inspected the engine and fuel system, and reported that prior to the removal of the wreckage from the field, the engine was started and run without any noted problems. He also said that fuel was drained from the aircraft and no contamination or water accumulation was noted. No anomalies or any evidence of a malfunction in the aircraft's systems were noted. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power, cruise - reason for occurrence undetermined (cause) - Forced landing, emergency descent/landing - autorotation - performed - On ground/water encounter with terrain/water, emergency landing - terrain condition - berm (contributing factor) ## Aircraft - Registration: [N206LT](https://openairdocs.org/deregistered/N206LT-2014-06-05), registration cancelled 2014-06-05, S/N 51069, built 1993 (OpenAirDocs) - Reported make and model: Bell 206L - Registry model: [Bell 206L-3](https://openairdocs.org/model/bell-206l-3) (registry code 1182108) (OpenAirDocs) - Registry engine: [Allison 250-C20 series](https://openairdocs.org/engine/allison-250-c20-series) (registry code 03020, turbo-prop) (OpenAirDocs) - Category: Helicopter - Serial number: 51069 - Airframe hours: 2985 - Engines: Allison 250-C30P 650 horsepower turbo shaft - Damage: Substantial damage - Flight: Positioning, Part 91 - Operator: Briles Helicopter - Registered owner: Tundra Copters, Inc. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, July 30, 1997, 78 hours before - Departed: IDA, ID - Destination: SLC, SALT LAKE CITY, UT ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 48; airline transport, flight instructor; airplane ratings: multi-engine land, single-engine land; instrument ratings: helicopter, airplane; medical: class 1, valid medical--w/ waivers/lim; seat: right; flight hours: 12,400 total, 1,000 in this make and model, 11,600 as pilot in command, 94 in the last 90 days, 40 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 230° at 5 knots - Visibility: 15 statute miles - Lowest ceiling: 4,000 ft broken - Temperature: 39 °F ## 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 19971216039119A](https://openairdocs.org/incident/19971216039119A), Dec 16, 1997: Bell 206L3, Idaho Falls, ID, Substantial damage. Engine lost power departing on ferry flight. Autorotated into rough terrain no defects noted sat idle for 2 months. (-23) see attached. No attachment. From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date; 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.