ASN Wikibase Occurrence # 225693
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| Date: | Thursday 28 September 2017 |
| Time: | 17:16 |
| Type: |  Piper PA-25-235 Pawnee |
| Owner/operator: | Private |
| Registration: | N7336Z |
| MSN: | 25-3285 |
| Year of manufacture: | 1965 |
| Engine model: | Lycoming O-540-B2B5 |
| Fatalities: | Fatalities: 0 / Occupants: 1 |
| Aircraft damage: | Substantial |
| Category: | Accident |
| Location: | Westphalia, KS -
 United States of America
|
| Phase: | |
| Nature: | Agricultural |
| Departure airport: | Garnett, KS (K68) |
| Garnett, KS (K68) | |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
The commercial pilot reported that he departed in the airplane with full fuel and chemical for the aerial application flight. After spraying a field for about 20 minutes, the engine experienced a total loss of power. The pilot jettisoned the chemical load and initiated a forced landing to a field. About 5 ft above the field, as the pilot tried to bleed off airspeed, the airplane stalled and impacted terrain.
Disassembly and examination of the engine revealed that the crankshaft was fractured, and the main bearings displayed thermal damage and smearing. Material examination of the crankshaft showed features consistent with a subsurface crack initiation and fatigue crack propagation. The fatigue striations, particularly near the initiation site, were consistent with high-cycle fatigue. The forward main bearings exhibited spalling, displacement, and cracking consistent with bearing wear fatigue. All the bearing damage was typical of similar bearings that had been operated at elevated temperatures using inadequate lubrication. The main bearing damage was likely the result of main bearing shift and a blockage of the lubrication paths. The blockage resulted in a lack of lubrication, main bearing failure, and a fatigue failure of the crankshaft. The reason for the main bearing shift could not be determined based on the available information.
Probable Cause: A total loss of engine power due to a fatigue failure of the crankshaft that resulted from main bearing shift and lack of lubrication.
Accident investigation:
 |
|
Sources:
NTSB
History of this aircraft
Other occurrences involving this aircraft
| 8 June 1985 | N7336Z | Private | 0 | Lovington, NM | |
sub |
Location
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 01-Jun-2019 07:29 | ASN Update Bot | Added |
Corrections or additions? ... Edit this accident description
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