# NTSB SEA98LA039: Cessna 150F, N8794G, Fife, WA, February 24, 1998 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: February 24, 1998, 14:30 local (22:30 UTC) - Place: Fife, WA - Coordinates: 47.580711, -121.880615 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=47.5807&lon=-121.8806&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report December 8, 1998 - Report: Approved by Office Director - NTSB case key (mKey): 42759 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA98LA039 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/42759/pdf - Page: https://openairdocs.org/ntsb/SEA98LA039 ## Probable cause The fracture separation of an exhaust valve head, followed by the total failure of the associated piston. A factor was the soft terrain at the location of the 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, maneuvering - engine assembly,valve,exhaust - fractured (cause) - engine assembly,piston - failure,total (cause) - Forced landing, emergency landing - Nose over, landing - roll - terrain condition - soft (contributing factor) ## Analysis The Subaru Legacy powered Cessna 150 experienced a partial loss of engine power about 30 minutes after takeoff. Soon thereafter, the engine lost all power, and the pilot executed a forced landing in a nearby field. Although the touchdown was successful, the nose gear dug into the soft terrain as the pilot applied brakes to stop short of an upcoming ditch. After the nose gear dug into the terrain, the aircraft flipped over onto its back. A teardown of the engine revealed that the head had fractured off one of the exhaust valves in the forward left cylinder, resulting in the destruction of the piston. ## Factual narrative On February 24, 1998, approximately 1430 Pacific standard time, an experimental Cessna 150F, N8794G, nosed over during the landing roll following a forced landing after a loss of engine power near Fife, Washington. The private pilot and his passenger were not injured, but the aircraft, which was owned and operated by the pilot, sustained substantial damage. The 14 CFR Part 91 flight, which departed Auburn Municipal Airport, Auburn, Washington, about 30 minutes earlier, was being operated in visual meteorological conditions. No flight plan had been filed, and there was no report of an ELT activation. According to the pilot, the aircraft, which was registered in the Experimental Exhibition category, was powered by a modified Subaru Legacy automobile engine. He said that while demonstrating the aircraft to an acquaintance, the engine experienced a partial power loss. Soon thereafter, the engine lost all power, and the pilot elected to land in a nearby farm field. He said that his touchdown on the soft terrain was successful, but as he applied brakes to stop prior to an upcoming ditch, the nose wheel dug into the soft terrain and the aircraft nosed over. Although the owner, who was the individual that modified the engine for aviation use, was quite sure that a camshaft gear locating pin had failed, an engine teardown revealed that was not the case. Instead, it was found that the head on one of the two exhaust valves in the forward left cylinder had broken off of its stem and fallen into the cylinder. The piston itself had been torn into numerous small pieces and much of it was found laying in the cylinder. The piston pin was still in the end of the connecting rod, but none of the piston was still attached to the pin. ## Aircraft - Registration: [N8794G](https://openairdocs.org/deregistered/N8794G-2019-10-11), registration cancelled 2019-10-11, S/N 15062894, built 1966 (OpenAirDocs) - Reported make and model: Cessna 150F - Registry model: [Cessna 150F](https://openairdocs.org/model/cessna-150f) (registry code 2071814) (OpenAirDocs) - Registry engine: [Lycoming O-320 series](https://openairdocs.org/engine/lycoming-o-320-series) (registry code 42389, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 15062894 - Airframe hours: 2500 - Engines: Subaru EJ22 180 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Reiner O. Hoffmann - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Annual, July 1, 1997, 45 hours before - Departed: S50, AUBURN, WA ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 36; private; airplane ratings: single-engine land; medical: class 3, expired; seat: left; flight hours: 800 total, 650 in this make and model, 800 as pilot in command, 10 in the last 90 days ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 20 statute miles - Lowest ceiling: none - Temperature: 55 °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 19980224025649A](https://openairdocs.org/incident/19980224025649A), Feb 24, 1998: Cessna 150F, Fife, WA, Substantial damage. (.4)The subaru legacy powered Cessna 150 experienced a partial loss of engine power about 30 minutes after takeoff. Soon thereafter, the engine lost all power,… 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.