Cessna 172P N54872

Summary

On 4 January 2012 at about 03:45 local time, a Cessna 172P registered N54872, operated by Civil Air Patrol, Inc., was involved in an accident near Conroe, Texas, 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

4 January 2012 at 03:45

Classification

Accident

Location

Conroe, Texas, United States

Coordinates

30.3086, -95.4500

Aircraft

Cessna 172P

Registration

N54872

Category

Airplane

Engines

1

Operator

Civil Air Patrol, Inc.

Operating rule

Public Use

Phase of flight

Not recorded

Route

Houston → Conroe

Aircraft damage

Substantial

Weather

VMC

Light

Night/Dark

NTSB number

CEN12TA122

Nobody was injured.

Failure of the rear crankshaft gear dowel pin due to improper installation, which resulted in a total loss of engine power.

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

Read the full NTSB narrative

The airplane was at 1,600 feet mean sea level with the engine power set at 2,300 rpm. When the airplane was about 6 miles from the airport, the pilot heard a loud “boom” and the engine lost all power. The pilot did not have sufficient altitude to glide to the airport, so he landed the airplane on a street. When the airplane was on final approach to land, it collided with power lines. The pilot was able to land the airplane, but was forced to swerve to the right to avoid oncoming traffic. The right wing struck a utility pole, which resulted in substantial damage. A postaccident engine examination revealed that when the crankshaft was turned, there was no movement of the intake or exhaust valves or magneto gears. The rear crank gear bolt was loose and the gear dowel pin was sheared, which would cause the camshaft and rear accessory gears to stop turning. Metallurgical examination revealed beach markings at the aft end of the crankshaft approximately in plane with the aft face of the crankshaft where it mated to the crankshaft gear. There was fretting damage on the crankshaft gear, wear on the dowel pins, and wear on the lock washer, indicative of movement as a result of insufficient clamping force from the attachment bolt at the time of installation. The engine had accrued 752 hours since it was overhauled in August 2007.

Quoted verbatim from the NTSB record.