SEA04LA033 · Cessna 172RG
Cessna 172RG · Accident: loss of engine power while maneuvering
From King County International Airport - Boeing Field (BFI) to King County International Airport - Boeing Field (BFI)
Event
- NTSB case
- SEA04LA033
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Cessna 172RG
- Aircraft type
- Cessna 172
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N64ML
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From King County International Airport - Boeing Field (BFI), Seattle, WATo King County International Airport - Boeing Field (BFI)
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 91: General Aviation
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Maneuvering
- First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Loss of engine power
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Engine assembly, valve lifter › Fractured
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
During a power-on stall sequence the aircraft's engine experienced a significant partial power loss, followed by the engine oil pressure dropping to zero. Since there was no suitable landing area directly below the area where the power loss occurred, the pilot headed to the south and attempted to land on what appeared to be the only available reasonably safe terrain. Based upon his quick evaluation of the landing site, the pilot chose to leave the gear fully retracted. Although the initial touchdown was uneventful, soon thereafter the aircraft contacted the rough/uneven terrain in a manner that resulted in substantial damage to the airframe. A post-accident inspection of the engine revealed that the crankcase mating flange was cracked in two different places, and the number three cylinder push rod and push rod tube were bent in a manner consistent with compression of the pushrod from its ends. The heads of six of the eight cam followers had fractured, the crankcase surface behind all but two of the follower heads was dented and gouged, and the crankcase surface behind two of the heads had small chunks of fractured steel imbedded/crushed into the metal of the case. Removal of the oil pan revealed about a dozen pieces of metal that were clearly identifiable as sections of the cam follower heads. Further inspection of the engine and its cylinders could not determine the initiating event leading to the fracturing of the cam followers.
Probable cause
A loss of engine power while maneuvering due to the failure of the heads of six of the eight cam followers. Factors include the pilot's decision to keep the gear retracted during the forced landing, and the rough/uneven terrain.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record SEA04LA033
- Event ID
- 20040115X00067
- Case number
- SEA04LA033
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status, coordinates. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: c78a2554afb1adca57d1b34597ac20fb070fb92f37e5630e9b70223daa8314c1; retrieved 2026-09-22T08:01:41.990Z.