# NTSB LAX08LA196: Schweizer 269C, N432MS, Buffalo, WY, June 24, 2008 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: June 24, 2008, 13:45 local (19:45 UTC) - Place: Buffalo, WY - Coordinates: 44.322498, -106.261108 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=44.3225&lon=-106.2611&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff-rejected takeoff: Collision during takeoff/land](https://openairdocs.org/ntsb-events/490) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report January 29, 2009 - Report: Approved by Office Director - Parties: Federal Aviation Administration FSDO - NTSB case key (mKey): 68317 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX08LA196 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/68317/pdf - Page: https://openairdocs.org/ntsb/LAX08LA196 ## Probable cause The pilot's attempted downwind takeoff that resulted in an aborted takeoff. Contributing to the accident was the unsuitable terrain. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Wind: tailwind](https://openairdocs.org/ntsb-findings/03034015): Environmental issues › Conditions/weather/phenomena · Decision related to condition (probable cause); cases with it: [Schweizer 269C, 2 cases](https://openairdocs.org/ntsb-findings/03034015/cases.md?model=8059502), [All aircraft, 594 cases](https://openairdocs.org/ntsb-findings/03034015/cases.md) - [Terrain: sloped/uneven terrain](https://openairdocs.org/ntsb-findings/03021017): Environmental issues › Physical environment · Contributed to outcome (probable cause); cases with it: [Schweizer 269C, 3 cases](https://openairdocs.org/ntsb-findings/03021017/cases.md?model=8059502), [All aircraft, 270 cases](https://openairdocs.org/ntsb-findings/03021017/cases.md) - [Aircraft capability: climb capability](https://openairdocs.org/ntsb-findings/01061010): Aircraft › Aircraft oper/perf/capability · Not attained/maintained; cases with it: [Schweizer 269C, 2 cases](https://openairdocs.org/ntsb-findings/01061010/cases.md?model=8059502), [All aircraft, 183 cases](https://openairdocs.org/ntsb-findings/01061010/cases.md) - [Wind: tailwind](https://openairdocs.org/ntsb-findings/03034015): Environmental issues › Conditions/weather/phenomena · Effect on operation (probable cause); cases with it: [Schweizer 269C, 2 cases](https://openairdocs.org/ntsb-findings/03034015/cases.md?model=8059502), [All aircraft, 594 cases](https://openairdocs.org/ntsb-findings/03034015/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Takeoff-rejected takeoff: Collision during takeoff/land](https://openairdocs.org/ntsb-events/490) (defining event); cases with it: [Schweizer 269C, 2 cases](https://openairdocs.org/ntsb-events/490/sequence.md?model=8059502), [All aircraft, 1,309 cases](https://openairdocs.org/ntsb-events/490/sequence.md) ## Analysis The helicopter pilot was picking up a biologist who was conducting land surveys. Prior to landing he circled the landing zone to observe the wind conditions. During the landing approach he transitioned out of effective translational lift earlier than expected, and attributed this to a reduced headwind caused by the enclosed terrain. During departure and acceleration to effective translational lift speed, the rotor speed began to decay. The ground speed was faster than he anticipated so he lowered the collective, and added forward cyclic, but could not maintain enough rotor speed for sustained flight. The pilot elected to land the helicopter ahead on a 30-degree uphill slope. After landing, the helicopter rolled back and the tail rotor made contact with the ground causing substantial damage to the tail rotor drive system. After the accident the pilot noted that the winds had shifted 180 degrees from his initial pre-accident observation. ## Factual narrative On June 24, 2008, about 1345 mountain daylight time, a Schweizer 269C, N432MS, collided with terrain during takeoff near Buffalo, Wyoming. Northern Skies Aviation, Inc., was operating the helicopter under the provisions of 14 Code of Federal Regulations Part 135. The certificated airline transport pilot and passenger were not injured; the helicopter sustained substantial damage. The local passenger-repositioning flight departed from a landing zone 22 miles east of Buffalo, just prior to the accident. Visual meteorological conditions prevailed, and no flight plan had been filed. In a written statement, the pilot reported that the purpose of the flight was to pickup a biologist who was conducting land surveys. He reported arriving at the landing zone and circling the area to assess the wind conditions. He noted the landing zone was within a 3/4-mile diameter bowl like depression. He landed to pickup the passenger and noted that he transitioned out of effective translational lift (ETL) earlier than expected. He attributed this phenomena to a reduced headwind caused by the enclosed terrain. He loaded the passenger and they departed; however, during acceleration to ETL speed the pilot reported that the rotor speed began to decay. He observed that his ground speed was faster than he anticipated. He lowered the collective, and added forward cyclic, but could not maintain enough rotor speed for sustained flight. He flew the helicopter 1/4 mile further trying to locate a safe landing area. With airspeed and rotor speed decaying, the pilot elected to land the helicopter ahead on a 30-degree uphill slope. After landing, the helicopter rolled back and the tail rotor made contact with the ground causing substantial damage to the tail rotor drive system. After the accident the pilot walked up an embankment above the accident site to observe the wind conditions. He noted that the winds had shifted 180 degrees from his initial pre-accident observation. The accident occurred at an altitude of approximately 4,300 feet mean sea level (msl). The closest official weather observation station was Johnson County Airport, Buffalo, located about 24 miles west of the accident site. The elevation of the weather reporting station was 4,968 feet msl. An aviation routine weather report was issued at 1353. It stated: winds from 010 degrees at 13 knots, gusting to 19 knots; visibility 10 statute miles; clear skies; temperature 28 degrees Celsius; dew point 12 degrees Celsius; altimeter 30.01 inches of mercury. The pilot stated that the helicopter and engine had no mechanical failures or malfunctions during the flight. ## Aircraft - Registration: [N432MS](https://openairdocs.org/deregistered/N432MS-2018-03-08), registration cancelled 2018-03-08, S/N S1437, built 1990 (OpenAirDocs) - Reported make and model: SCHWEIZER 269C - Registry model: [Schweizer 269C](https://openairdocs.org/model/schweizer-269c) (registry code 8059502) (OpenAirDocs) - Registry engine: [Lycoming HIO-360 series](https://openairdocs.org/engine/lycoming-hio-360-series) (registry code 41524, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: S1437 - Airframe hours: 3293 - Engines: Lycoming HIO-360-D1A 190 horsepower reciprocating - Damage: Substantial damage - Flight: Part 135 - Operator: Northern Skies Aviation Inc., doing business as Northern Skies Aviation Inc - Registered owner: Northern Skies Aviation Inc. - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, June 11, 2008, 42 hours before - Departed: Buffalo, WY - Destination: Buffalo, WY - Airport: KBYG, Johnson County Airport ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 53; injuries: none; commercial, airline transport; airplane ratings: multi-engine land, single-engine sea, single-engine land; instrument ratings: airplane, helicopter; medical: class 2, with waivers/limitations; last flight review March 21, 2008; seat: left; flight hours: 17,256 total, 2,310 in this make and model, 15,724 as pilot in command, 151 in the last 90 days, 93 in the last 30 days, 6 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 10° at 13 knots, gusting 19 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 82 °F, dew point 54 °F - Altimeter: 30.01 inHg - Observed at: KBYG, 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 20080624841529A](https://openairdocs.org/incident/20080624841529A), Jun 24, 2008: Hughes 269C, Buffalo, WY, Substantial damage. (-23)On a steep departure takeoff, aircraft lost rotor RPM because of a wind switch. Aircraft lost altitude and stuck vegetation. 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.