Air Tractor AT 301 N23923

Summary

On 2 August 2016 at about 15:35 local time, a Air Tractor AT 301 registered N23923 was involved in an accident near Weiser, Idaho, 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

2 August 2016 at 15:35

Classification

Accident

Location

Weiser, Idaho, United States

Coordinates

44.2203, -116.9075

Aircraft

Air Tractor AT 301

Registration

N23923

Category

Airplane

Year built

1982

Engines

1

Operator

Not recorded

Operating rule

Part 137: Agricultural

Purpose of flight

Aerial Application

Phase of flight

Not recorded

Route

Weiser → Weiser

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR16LA159

Nobody was injured.

A partial loss of engine power due to an internal catastrophic failure of the master rod crankpin bearing.

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

Read the full NTSB narrative

The airline transport pilot reported that, during an aerial application flight, he observed rising engine cylinder head temperatures and a partial loss of engine power. Unable to maintain altitude, he jettisoned the load of liquid fertilizer and made a forced landing to an alfalfa field. During the landing, the airplane collided with a wheel line sprinkler system. A postaccident examination of the radial engine revealed damage to the No. 1 cylinder lower piston skirt and the oil scraper ring. The inside of the piston exhibited multiple indentations consistent with continued battering. The remaining eight cylinders and pistons were removed and exhibited similar signatures. Multiple metallic fragments that resembled bearing material were found in the crankcase, and the magnetic chip detector displayed metallic debris. The master rod and link rod assembly were removed from the crankshaft, and the front side of the master rod exhibited two perpendicular dents. The master rod crankpin bearing revealed substantial wear and gouging-type damage, consistent with its failure initiating the engine failure. The master rod crankpin bearing was thinned, or gouged out, consistent with the metallic shavings found in the crankcase and oil galley. No maintenance records were provided, and the engine's service and maintenance history could not be determined.

Quoted verbatim from the NTSB record.