Accident Air Tractor AT-301 N23923,
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ASN Wikibase Occurrence # 215449
 
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Date:Tuesday 2 August 2016
Time:09:35
Type:Silhouette image of generic AT3P model; specific model in this crash may look slightly different    
Air Tractor AT-301
Owner/operator:Private
Registration: N23923
MSN: 301-0466
Year of manufacture:1982
Engine model:P&W R1340 SERIES
Fatalities:Fatalities: 0 / Occupants: 1
Aircraft damage: Substantial
Category:Accident
Location:Weiser, ID -   United States of America
Phase: Manoeuvring (airshow, firefighting, ag.ops.)
Nature:Agricultural
Departure airport:Weiser, ID (S87)
Destination airport:Weiser, ID (S87)
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
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.


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


Accident investigation:
cover
  
Investigating agency: NTSB
Report number: WPR16LA159
Status: Investigation completed
Duration: 2 years 1 month
Download report: Final report

Sources:

NTSB

Location

Revision history:

Date/timeContributorUpdates
16-Sep-2018 19:09 ASN Update Bot Added

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