FlightFinder
Check my flight
Casualties unknown

Air Tractor AT-301 accident at Roberts, ID, 17 Jul 1995 (N4326S)

Roberts, ID, US

On July 17, 1995, an Air Tractor AT-301 (registration N4326S) was involved in an aviation accident near Roberts, ID. Investigators recorded the probable cause as: A LOSS OF ENGINE POWER DUE TO THE SEPARATION OF THE NUMBER 3 CYLINDER EXHAUST VALVE ROCKER ARM SHAFT FROM THE CYLINDER HEAD, WHICH DISABLED MOVEMENT OF THE EXHAUST VALVE. A FACTOR WAS THE LACK OF SUITABLE TERRAIN FOR THE FORCED LANDING. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 2026-06-10Data APIEditorial standards

Probable cause

A LOSS OF ENGINE POWER DUE TO THE SEPARATION OF THE NUMBER 3 CYLINDER EXHAUST VALVE ROCKER ARM SHAFT FROM THE CYLINDER HEAD, WHICH DISABLED MOVEMENT OF THE EXHAUST VALVE. A FACTOR WAS THE LACK OF SUITABLE TERRAIN FOR THE FORCED LANDING.

— NTSB Determination

Accident narrative

THE PILOT REPORTED THAT SHORTLY AFTER TAKEOFF, AT 40 FEET ABOVE GROUND LEVEL, THE ENGINE LOST POWER AND BEGAN BACKFIRING. THE PILOT MADE A FORCED LANDING IN A BARLEY FIELD WITH 3-FOOT-TALL CROPS, AND THE AIRPLANE CARTWHEELED. POSTACCIDENT EXAMINATION OF THE ENGINE REVEALED THAT THE EXHAUST VALVE ROCKER ARM HOUSING ON THE NUMBER 3 CYLINDER SEPARATED, DISABLING THE NUMBER 3 CYLINDER EXHAUST VALVE.

Engine failure

More accident analyses

PKBWL Investigating Serious Incident Involving AT-3R100

The Polish aviation safety authority is investigating a serious incident involving an AT-3R100 aircraft that occurred on September 2, 2024. The investigation…

AERO AT-3 R-100Aeroklub Warszawski2024-09-02PKBWL Poland

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001207X04098. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.