Piper PA 25-235 N7336Z

Summary

On 28 September 2017 at about 22:16 local time, a Piper PA 25-235 registered N7336Z was involved in an accident near Westphalia, Kansas, 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

28 September 2017 at 22:16

Classification

Accident

Location

Westphalia, Kansas, United States

Coordinates

38.1850, -95.4836

Aircraft

Piper PA 25-235

Registration

N7336Z

Category

Airplane

Year built

1965

Engines

1

Operator

Not recorded

Operating rule

Part 137: Agricultural

Purpose of flight

Aerial Application

Phase of flight

Not recorded

Route

Garnett → Garnett

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

CEN17LA372

Nobody was injured.

A total loss of engine power due to a fatigue failure of the crankshaft that resulted from main bearing shift and lack of lubrication.

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

Read the full NTSB narrative

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.  

Quoted verbatim from the NTSB record.