Piper J3C N98550

Summary

On 13 August 2017 at about 21:00 local time, a Piper J3C registered N98550, operated by Berkshire Aviation Enterprises Inc, was involved in an accident near Salisbury, Connecticut, United States. 2 people were on board and 2 had minor injuries. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

13 August 2017 at 21:00

Classification

Accident

Location

Salisbury, Connecticut, United States

Coordinates

42.0350, -73.4339

Aircraft

Piper J3C

Registration

N98550

Category

Airplane

Year built

1946

Engines

1

Operator

Berkshire Aviation Enterprises Inc

Operating rule

Part 91: General Aviation

Purpose of flight

Instructional

Phase of flight

Not recorded

Route

Great Barringto → Great Barringto

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

ERA17LA275

2 people had minor injuries.

An improper replacement of the crankshaft by maintenance personnel, which resulted in a failure of the crankshaft gear and total loss of engine power.

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

Read the full NTSB narrative

During cruise flight, the airplane experienced a total loss of engine power, and the flight instructor performed a forced landing into trees. The engine crankshaft was replaced about 4 years and about 317 hours of operation before the accident. Teardown examination of the engine revealed that the crankshaft gear screws were fractured, and the crankshaft gear was separated from the crankshaft. Fretting was observed near two of the four crankshaft screw holes and corresponded to two elongated screw holes on the crankshaft gear. The crankshaft and crankshaft gear did not contain a dowel pin as specified in the most current versions of the manufacturer's illustrated parts catalog and overhaul manual, which were published more than 2 years before the crankshaft replacement. Additionally, the crankshaft gear did not contain a dowel pin hole, which was consistent with a crankshaft gear for an older, different model engine. Both publications contained numerous instructions and references to use a crankshaft gear with a dowel pin hole and to align the gear to the crankshaft with a dowel pin, which would pilot the crankshaft gear on the crankshaft. Thus, it is likely that when the crankshaft was replaced, maintenance personnel did not use the most recent manuals and installed a crankshaft gear for a different engine, which led to the crankshaft gear's failure and the subsequent loss of all engine power.

Quoted verbatim from the NTSB record.