LAX97LA018 · Cessna 172P
Sierra Academy Cessna 172P · Accident: total loss of engine power (mechanical failure) en route
From Livermore Municipal Airport (LVK) to Porterville Municipal Airport (PTV)
Event
- NTSB case
- LAX97LA018
- 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 172P
- 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
- N6187K
- Operator
- Sierra Academy
- Onboard fatalities
- Unknown
- Route
- From Livermore Municipal Airport (LVK), Livermore, CATo Porterville Municipal Airport (PTV), Porterville, CA
- 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
- Destroyed
Cause areas
- Engine assembly › Overtemperature
- Engine assembly, piston › Failure
- Miscellaneous, engine pre-ignition and/or detonation
- Pilot in command › Mixture, improper use of
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
As a student pilot was en route on his third supervised solo cross-country flight, the engine suddenly began running rough. Oil was observed to cover most of the front windscreen. Subsequently, the engine lost power, the student made a forced landing in a clearing, and the airplane collided with a tree and a building. An FAA inspector performed an examination of the wreckage, and observed a 2-inch diameter hole in the engine's upper case in the vicinity of the number 2 cylinder. A further examination revealed that the connecting rod to the number 2 piston was disconnected from the piston due to a failure of the piston skirt in the piston pin area. The rings on all pistons appeared to have been sticking, with over temperature signatures noted on all the intake and exhaust valves. The tops of the piston were abnormally clean. The engine had a total time of 3,794.5 hours since new and 1,987.0 hours since the last major overhaul.
Probable cause
the student pilot's use of an excessively lean mixture, which led to engine overheating, detonation, subsequent failure of the number 2 piston, and a forced landing.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record LAX97LA018
- Event ID
- 20001208X06927
- Case number
- LAX97LA018
- 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: 12f812d1cc89984ab0dd8ee47bde3d69bfd609d3a3c5376a230445a61fc12a34; retrieved 2026-09-21T21:33:48.282Z.