ANC96LA103 · Cessna 172XP
Cessna 172XP · Accident: total loss of engine power (mechanical failure) en route
From King Salmon Airport (AKN) to Merrill Field (MRI)
Event
- NTSB case
- ANC96LA103
- 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
- 0
- 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 172XP
- 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
- N736LB
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From King Salmon Airport (AKN), KING SALMON, AKTo Merrill Field (MRI), Anchorage, AK
- 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
- En route · cruise
- 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
- Total loss of engine power (mechanical failure)
- 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, bearing › Seized
- Engine assembly, connecting rod cap › Failure
- Engine assembly, connecting rod › Fractured
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot was exiting a mountain pass when the airplane's engine suddenly lost all power. His attempts at restarting the engine were unsuccessful, and he made an emergency landing on a rough gravel bar. During the engine examination, the #2 cylinder piston connecting rod was found fractured and separated from the crankshaft. The #2 piston connecting rod cap and cap bolts were also fractured and separated from the crankshaft. The #2 piston connecting rod journal was rough and abraded. The piston connecting rod cap bolts had fractured about mid span, and the fracture ends were stretched and necked down. The castellated nuts used to secure the rod cap were found still attached to their respective rod cap bolts. No other mechanical anomalies were discovered during the engine examination. The mechanic who recovered the airplane from the accident site indicated that he drained at least 6 quarts of oil from the engine prior to the recovery.
Probable cause
The loss of engine power due to seized piston connecting rod bearings, and subsequent failure of the piston connecting rod cap and fracture of the piston connecting rod. A factor associated with the accident was the rough and uneven emergency landing site.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record ANC96LA103
- Event ID
- 20001208X06138
- Case number
- ANC96LA103
- 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. 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: 6bcf45cde99df59b8d234a653592360d83ca5fafa3b841a67af72ced9b0a2eb4; retrieved 2026-09-22T21:46:15.120Z.