Piper PA28 N4139A

Summary

On 29 August 2018 at about 01:40 local time, a Piper PA28 registered N4139A was involved in an accident near Tat Momoli, Arizona, United States. 2 people were 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

29 August 2018 at 01:40

Classification

Accident

Location

Tat Momoli, Arizona, United States

Coordinates

32.6447, -111.8681

Aircraft

Piper PA28

Registration

N4139A

Category

Airplane

Year built

1998

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Nogales → Van Nuys

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR18LA248

Nobody was injured.

A total loss of engine power due to a fatigue crack in the connecting rod bushing end.

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

Read the full NTSB narrative

The pilot reported that during the cross-country flight, the engine experienced a total loss of power. The pilot initiated a forced landing to a nearby road where, during the landing roll, the airplane impacted a barbed wire fence, resulting in substantial damage to the right wing. Postaccident examination revealed a large hole in the engine case at the No. 4 cylinder that exposed the crankshaft and connecting rod. The No. 4 cylinder was seized, and the connecting rod was fractured at the piston end. Further examination revealed that the connecting rod fractured from a fatigue crack in the bore on the piston end, which likely initiated at an internal corner of the bore. The fatigue crack progressed through most of the pin bore cross-section. Following the fracture of the connecting rod, the continued movement of the broken part led to subsequent overstress fractures and damage to nearby components, which resulted in catastrophic engine failure and a complete seizure of the engine. The cause of the fatigue crack initiation could not be determined, as both the initiation site (or sites) and the termination of the fatigue crack were destroyed by postfracture impact damage. The general location of the initiation, the internal corner of the pin bore, suggested the presence of concentrated stress in that location, which could have been the result of a material defect, such as a pore, inclusion, or corrosion pit that may have occurred when the connecting rod was rebushed. A crack initiation could also have been the result of improper sizing of the internal bushing, improper installation of the connecting rod, or use of the wrong parts. The engine was overhauled 42 flight hours before the accident.

Quoted verbatim from the NTSB record.