Beechcraft A36 N7214Y

Summary

On 9 June 2008 at about 01:30 local time, a Beechcraft A36 registered N7214Y was involved in an accident near Grand Rapids, Minnesota, United States. 3 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

9 June 2008 at 01:30

Classification

Accident

Location

Grand Rapids, Minnesota, United States

Nearest airport

Grand Rapids/Itasca County (GPZ)

Coordinates

47.2111, -93.5097

Aircraft

Beechcraft A36

Registration

N7214Y

Category

Airplane

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

International F → Minneapolis

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

CHI08LA154

Nobody was injured.

A loss of engine thrust due to the propeller separating from the aircraft as a result of fatigue failure of the propeller attachment bolts caused by the insufficient torque of the bolts during installation.

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

Read the full NTSB narrative

The pilot stated that about 40 minutes into the flight he heard a loud noise followed by a rapid deceleration of the engine, and then a "distinct bang." The windshield was immediately covered with a film of oil, completely obstructing forward visibility. He established a descent at best glide airspeed and established a course for the nearest suitable airport. During the descent, the engine continued to run rough and smoke entered the cockpit. It became apparent to the pilot that he did not have enough altitude to reach the airport. He attempted to increase engine power in order to slow the descent; however, the engine seized shortly afterward. He set up for a forced landing to a clearing adjacent to a set of power lines. During the forced landing, the airplane impacted trees and a utility pole, which separated the left tip tank and left aileron from the airframe. The airplane slid approximately 50 feet and came to rest upright. A postaccident inspection revealed that the propeller assembly had separated from the engine propeller flange. The propeller flange appeared intact. The propeller assembly was not recovered. Two propeller bolt fragments and one propeller alignment pin fragment were recovered from the engine cowling. Examination of the fracture surfaces revealed features consistent with reverse bending fatigue cracking. In addition, the washer faces of both nuts were worn and polished consistent with relative movement against the crankshaft flange. Maintenance records indicated that the propeller spinner bulkhead was replaced approximately one year prior to the accident in order to comply with a manufacturer's service letter. At the time of the accident, the propeller assembly had accumulated 1,906 hours total time in service, with 235 hours since replacement of the spinner bulkhead. About 531 hours had accumulated since overhaul of the propeller assembly.

Quoted verbatim from the NTSB record.