Air Tractor AT-401 N4543F

Summary

On 4 August 1995 at about 14:45 local time, a Air Tractor AT-401 registered N4543F was involved in an accident near Aurora, Nebraska, United States. One person was on board and nobody was injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

4 August 1995 at 14:45

Classification

Accident

Location

Aurora, Nebraska, United States

Coordinates

40.8598, -97.9999

Aircraft

Air Tractor AT-401

Registration

N4543F

Category

Airplane

Engines

1

Operator

Not recorded

Operating rule

Part 137: Agricultural

Purpose of flight

Aerial Application

Phase of flight

Not recorded

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

CHI95LA258

Nobody was injured.

the cracked engine assembly that caused the power loss during a critical phase of flight. Factors associated with this accident were the restricted airplane performance due to the power loss, the airplane's altitude was too low, and remedial action, by, the pilot, that would lead to an uneventful forced landing was not possible.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

AT THE BEGINNING OF THE PILOT'S SWATH RUN HE NOTICED WHITE SMOKE COMING FROM THE RIGHT SIDE OF THE ENGINE. HE SAID HE DISCONTINUED THE RUN AND TURNED BACK TOWARD HIS HOME AIRPORT. JUST AS THE AIRPLANE LEVELED OUT FROM ITS TURN THE PILOT SAID THE ENGINE LOST MOST OF ITS POWER. THE PILOT SAID HE HEADED THE AIRPLANE FOR A PASTURE BUT WAS UNABLE TO GLIDE TO IT. THE AIRPLANE NOSED OVER SHORTLY AFTER ITS WHEELS CONTACTED THE CORN, COMING TO REST ON THE GROUND. EXAMINATION OF THE ENGINE REVEALED THE NUMBER 4 CYLINDER'S EXHAUST TOWER WAS CRACKED WHERE THE ROCKER ARM SHAFT WENT THROUGH THE CYLINDER HEAD. THE OWNER/MECHANIC OF THE AIRPLANE SAID THE CONDITION RESULTING FROM THE DAMAGED EXHAUST TOWER PREVENTS THE CYLINDER'S EXHAUST VALVE FROM OPENING. THE RESULT OF THE EXHAUST VALVE NOT OPENING CREATES A BLOW BACK CONDITION THAT AFFECTS THE OTHER CYLINDERS. THE END RESULT, ACCORDING TO THE OWNER, IS THAT THE ENGINE WILL LOSE MOST OF ITS POWER. THIS WAS CONFIRMED BY THE FAA PRINCIPAL MAINTENANCE INSPECTOR WHO CONDUCTED THE ENGINE EXAMINATION.

Quoted verbatim from the NTSB record.