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Atlas / NTSB / SEA99LA092

NTSB CAROL · Event

Event SEA99LA092

1999-06-22 SHELTON, Washington, United States Airport · SHN None 1 aircraft Status: Completed

Aircraft involved

Probable cause & findings

The pilot's failure to maintain rotor RPM during an autorotation.

Factual narrative

On June 22, 1999, about 1430 Pacific daylight time, a Hughes 369D, N1089Y, registered to and operated by Olympic Air, Incorporated, was substantially damaged during landing following a practice autorotation. The accident occurred at Shelton Airport, Shelton, Washington. The commercial pilot, the sole occupant of the aircraft, was not injured. A company VFR flight plan was filed and visual meteorological conditions prevailed for this 14CFR91 flight. The flight originated from Rockaway, Oregon, approximately one hour prior to the accident. The pilot stated he was practicing autorotations from an altitude of approximately 200 feet above ground level (AGL) and an airspeed of approximately 50 knots. During the second practice autorotation, the pilot reduced power with throttle and used collective to adjust rotor speed to 410 RPM (minimum RPM for practice autorotations). The pilot stated the rotor RPM "quickly" decayed and the aircraft rapidly started to descend. Before the pilot was able to recover, the aircraft collided with the ground and rolled over. The aircraft sustained substantial damage to the main rotor blades, tail rotor, tail boom and fuselage. The pilot reported no mechanical failures or malfunctions with the aircraft at the time of the accident. The pilot was practicing autorotations from an altitude of approximately 200 feet above ground level (AGL) and an airspeed of approximately 50 knots. During the second practice autorotation, the pilot reduced power with throttle and used collective to adjust rotor speed to 410 RPM (minimum RPM for practice autorotations). The rotor RPM decreased below 410 RPM and the aircraft rapidly started to descend. Before the pilot was able to recover, the aircraft collided with the ground and rolled over. The aircraft sustained substantial damage to the main rotor blades, tail rotor, tail boom and fuselage. The pilot reported no mechanical failures or malfunctions with the aircraft at the time of the accident. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12

Verbatim from NTSB's published report. Source file NTSB_1999_SEA99LA092.txt. Findings + structured fields enriched from FAA avall.mdb. Full investigation docket on data.ntsb.gov ↗.

Related research

What the literature says.

Academic papers and agency reports matching this event's aircraft type or causal vocabulary (icing). Sourced from NASA NTRS, NTSB Safety Studies, FAA CAMI, AOPA Air Safety Institute, Embry-Riddle Scholarly Commons, arXiv, and the Semantic Scholar academic graph.

Browse the full corpus — academia portal ↗