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LAX91LA260 · Piper PA-22-135

16 Jun 1991 · SONITA, AZ, United States

Piper PA-22-135 · Accident: loss of engine power en route

From Ryan Field (RYN) to Sierra Vista Municipal Airport / Libby Army Air Field (FHU)

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Event

NTSB case
LAX91LA260
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

Piper PA-22-135

Aircraft type
Piper PA-22
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
N1429C
Onboard fatalities
Unknown
Route
From Ryan Field (RYN), Tucson, AZTo Sierra Vista Municipal Airport / Libby Army Air Field (FHU), FT. HUACHUCA, AZ
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
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 › Failure, partial
  • Engine assembly, ring › Cracked

Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.

NTSB narrative

DURING CRUISE FLIGHT, THE AIRPLANE'S ENGINE BEGAN TO RUN ROUGH. THE PILOT EXECUTED EMERGENCY PROCEDURES TO TRY TO REGAIN ADEQUATE POWER. THE POWER WAS NOT RESTORED AND THE AIRCRAFT COULD NOT MAINTAIN LEVEL FLIGHT. THE PILOT EXECUTED A FORCED LANDING TO A FIELD. DURING THE LANDING ROLL, THE AIRCRAFT COLLIDED WITH A DITCH, TRAVELED ABOUT 20 YARDS, AND NOSED OVER. EXAMINATION OF THE AIRCRAFT'S ENGINE REVEALED THAT A PISTON RING IN THE NUMBER 3 CYLINDER WAS BROKEN WHICH ALLOWED BLOW BY IN THE CYLINDER. THE PILOT SAID THAT HE HAD VAPOR LOCK. HE TOLD AN FAA SAFETY INSPECTOR THAT HE HAD USED AUTOMOBILE GAS FOR THE FLIGHT AND THE GAS WAS TRANSPORTED USING 'OLD CANS' FROM HIS FATHER'S HOUSE. NO EVIDENCE WAS FOUND TO INDICATE THAT THE AIRCRAFT'S ENGINE HAD VAPOR LOCK.

Probable cause

A LOSS OF ENGINE POWER DUE TO A BROKEN PISTON RING IN THE NUMBER 3 CYLINDER, WHICH RESULTED IN THE AIRCRAFT'S INABILITY TO MAINTAIN LEVEL FLIGHT.

Verbatim NTSB analysis and probable cause from the NTSB dataset

Sources

NTSB record LAX91LA260
Event ID
20001212X17311
Case number
LAX91LA260
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: 1ae9a37d453fcaa3843df830d961ee81fde81d27fabf17f18ab0e110d7ef51e1; retrieved 2026-09-23T04:04:02.624Z.