Piper PA-25-235 N7279Z

Summary

On 11 May 2015 at about 01:15 local time, a Piper PA-25-235 registered N7279Z was involved in an accident near Omega, Oklahoma, 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

11 May 2015 at 01:15

Classification

Accident

Location

Omega, Oklahoma, United States

Coordinates

35.8703, -98.1978

Aircraft

Piper PA-25-235

Registration

N7279Z

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

Watonga → Watonga

Aircraft damage

Substantial

Weather

VMC

Light

Dusk

NTSB number

CEN15LA238

Nobody was injured.

Improper base metal preparation or contamination of the No. 5 cylinder wall before it was coated, which resulted in the coating peeling off of the cylinder wall and contaminating the engine oil and the subsequent partial loss of engine power.

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

Read the full NTSB narrative

The commercial pilot was conducting an agricultural application flight. During the flight, the airplane was unable to maintain altitude, and the pilot conducted an emergency landing on a dirt road. During the landing roll, the left wing struck a fence, crushing the leading edge. The pilot reported that the oil temperature was extremely high and that the engine was having a problem producing power. A postaccident engine examination revealed metal particles in the engine oil, oil pump, and oil sump. The oil was black and smelled burnt. Coating was peeling off of the No. 5 cylinder wall. Energy dispersive spectroscopy analysis of the cylinder base metal produced a spectrum consistent with a steel alloy; the spectrum of the coating was consistent with a nickel-silicon carbide. It is likely that the coating was peeling either due to improper base metal preparation or contamination of the cylinder wall before it was coated, which resulted in poor bond strength between the coating and inner wall of the barrel. The metal particles from the peeled coating contaminated the engine oil and resulted in the partial loss of power.

Quoted verbatim from the NTSB record.