Pilot Debrief

CESSNA P210N near Caledonia, MI — 2010-09-06

Final reportCEN10FA521
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Date
2010-09-06
Location
Caledonia, MI, USA
Airport
GRR
Aircraft
CESSNA P210N
Registration
N4632A
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Maneuvering

Probable cause

A loss of engine power as a result of a fatigue failure of the crankshaft due to the loss of engine case through-bolt torque. Contributing to the accident was a mechanic's use of incorrect hardware.

NTSB narrative

The pilot and certified flight instructor were in a holding pattern during an instrument proficiency check when they heard a bang from the airplane's engine area. They initiated a forced landing and the airplane impacted terrain at the base of a hill. Fuel leaked and a ground fire ensued, resulting in substantial damage to the left wing. No airframe preimpact anomalies were observed on-scene. An engine teardown inspection revealed a separation of the crankshaft No. 3 short cheek consistent with fatigue. Additionally, the No. 2 lower through-bolt had the lowest torque value of all bolts and incorrect hardware was used on that through-bolt. Fretting was observed on the mating surfaces of the main bearing supports near the No. 2 through-bolt and its bearing had spun out of its support. Engine logbook entries indicated a mechanic replaced cylinders that would have required the removal and installation of hardware on the No. 2 through-bolt, approximately 19 months prior to the accident.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Pilot could have aborted the maneuver after hearing the engine bang.

NTSB coding

Evidence available

  • Photos
  • 5 docket documents
View NTSB final reportView NTSB docket

Docket documents5

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