Cessna 172S N957TA

Summary

On 31 July 2017 at about 19:30 local time, a Cessna 172S registered N957TA was involved in an accident near Seattle, Washington, 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

31 July 2017 at 19:30

Classification

Accident

Location

Seattle, Washington, United States

Coordinates

47.5486, -122.4014

Aircraft

Cessna 172S

Registration

N957TA

Category

Airplane

Year built

2002

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Instructional

Phase of flight

Not recorded

Route

Seattle → Seattle

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR17LA176

2 people had minor injuries.

The total loss of engine power due to oil starvation as a result of the loose right magneto, which allowed oil to escape and the engine to seize. Contributing to the accident was inadequate maintenance, which failed to identify the loose magneto bolt.

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

Read the full NTSB narrative

During an instructional flight, the engine started running rough and, shortly after the oil pressure light illuminated, subsequently quit. The pilot elected to ditch the airplane in the water close to the shoreline. An onsite examination of the engine revealed that the top bolt of the right magneto was loose and had backed off, which allowed the magneto to become partially separated, leaving a 3/8-inch gap at the top of the magneto where it mounted to the case, which allowed oil to exit the engine. Metal shavings were observed throughout the engine. A review of the maintenance records indicated that the magnetos were removed and overhauled about 9 months before the accident during a 500-hour inspection, which was 420.5 hours of flight time before the accident. The airplane had accumulated about 22 hours of flight time since its last annual inspection, and the loose magneto bolt should have been able to be identified at that time.

Quoted verbatim from the NTSB record.