Cessna 172 N7966B

Summary

On 15 August 1998 at about 22:15 local time, a Cessna 172 registered N7966B was involved in an accident near Palmer, Alaska, 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

15 August 1998 at 22:15

Classification

Accident

Location

Palmer, Alaska, United States

Nearest airport

Palmer Municipal Airport (PAQ)

Coordinates

61.6195, -148.9791

Aircraft

Cessna 172

Registration

N7966B

Category

Airplane

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Instructional

Phase of flight

Not recorded

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

ANC98LA131

Nobody was injured.

Fatigue of the forward end of the engine crankshaft resulting in separation of the propeller assembly, and the operator's failure to comply with a required maintenance procedure. A factor was uneven terrain.

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

Read the full NTSB narrative

The student pilot was departing on runway 15, on his first solo flight. He stated that during the initial climb, the engine developed a severe vibration followed by a 'very loud bang'. He made a forced landing on a golf course at the southeast end of the airport. During the landing roll, the airplane's right wing struck a small hill, and sustained substantial damage. After landing, the pilot discovered that the entire propeller, propeller flange, and the forward end of the engine crankshaft were missing. They were later located near the midpoint of the departure runway. An FAA airworthiness inspector's review of the engine log book discovered that the accident engine had previously sustained two propeller strikes. He reported that the log book failed to reflect any inspection following the prop strikes. An NTSB metallurgical examination of the propeller flange assembly revealed multiple clamshell marks, typical of fatigue cracking. The engine is the subject of a Lycoming Engine Service Letter, L163C, that recommends that any engine involved in a sudden stoppage event be removed, dissembled, and inspected prior to returning the engine to service.

Quoted verbatim from the NTSB record.