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ASN Wikibase Occurrence # 173661
Last updated: 8 November 2019
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Date:10-JAN-1999
Time:13:30
Type:Silhouette image of generic C207 model; specific model in this crash may look slightly different
Cessna 207(F)
Owner/operator:Village Aviation, Inc.
Registration: N6312H
C/n / msn: 20700478
Fatalities:Fatalities: 0 / Occupants: 1
Other fatalities:0
Aircraft damage: Substantial
Category:Accident
Location:1,6 km SE of Quinhagak AP, AK -   United States of America
Phase: Unknown
Nature:Unknown
Departure airport:Bethel, AK (BET)
Destination airport:
Investigating agency: NTSB
Narrative:
The certificated commercial pilot reported that during the initial descent to land, the engine began to run rough and lose power. He noted that the roughness improved momentarily, followed by a severe engine vibration, and complete loss of engine power. The pilot selected a forced landing area on snow and tree-covered terrain. The airplane sustained substantial damage to the landing gear, fuselage, and wings. Postaccident investigation discovered that the engine crankshaft had sustained a complete fracture of the #2 cheek. A subsequent investigation revealed that on some crankshafts, a crack in the nitride layer that originated from a shallow tool mark, would in some cases ultimately lead to the fatigue failure of the crankshaft cheek. On April 22, 1999, the FAA issued an emergency airworthiness directive (AD) requiring that all TCM 470, 520, and 550 engine crankshafts manufactured in 1998, with less than 300 hours in service, will be inspected in accordance with the TCM critical service bulletin (CSB) within 10 hours of operation.

Probable Cause: Loss of engine power due to fracture of the engine crankshaft, and the manufacturer's improper manufacturing procedure during engine assembly. Factors associated with the accident were the manufacturer's inadequate quality control standards, trees, and snow-covered terrain.

Sources:

20700478


Revision history:

Date/timeContributorUpdates
09-Feb-2015 12:11 harro Added
09-Feb-2015 12:19 harro Updated [Embed code, Narrative]
09-Feb-2015 22:33 Geno Updated [Aircraft type, Location, Departure airport, Source]
23-Feb-2017 14:54 TB Updated [Date, Time, Aircraft type, Registration, Cn, Operator, Total occupants, Location, Country, Phase, Nature, Departure airport, Destination airport, Source, Embed code, Damage, Narrative]
25-Nov-2017 12:47 ASN Update Bot Updated [Time, Cn, Operator, Nature, Departure airport, Destination airport, Source, Narrative]
14-Dec-2017 16:55 ASN Update Bot Updated [Cn, Operator, Nature, Departure airport, Destination airport, Narrative]

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