ASN Wikibase Occurrence # 358961
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Date: | Thursday 25 May 1995 |
Time: | 10:00 LT |
Type: | Cessna 206 |
Owner/operator: | Arctic Circle Air Service Inc. |
Registration: | N19BR |
MSN: | U206002992 |
Total airframe hrs: | 6615 hours |
Engine model: | CONTINENTAL IO-520-F |
Fatalities: | Fatalities: 0 / Occupants: 1 |
Aircraft damage: | Substantial |
Category: | Accident |
Location: | Bethel, AK -
United States of America
|
Phase: | En route |
Nature: | Unknown |
Departure airport: | , AK (KBET) |
Destination airport: | Chevak, AK (VAK) |
Investigating agency: | NTSB |
Confidence Rating: | Accident investigation report completed and information captured |
Narrative:THE COMMERCIAL PILOT DEPARTED ON AN AIR TAXI CARGO FLIGHT TO A REMOTE DESTINATION. ABOUT 20 MINUTES AFTER TAKEOFF, THE ENGINE SUDDENLY QUIT, AND THE PILOT PERFORMED AN EMERGENCY LANDING ON ROUGH TERRAIN IN A STREAM BED. AFTER RECOVERY OF THE AIRPLANE 5 MONTHS LATER, AN EXAMINATION OF THE ENGINE REVEALED THAT THE #2 MAIN BEARING HAD FAILED AND THE CRANKSHAFT HAD FRACTURED THROUGH THE CRANK CHEEK BETWEEN THE #2 ROD AND #2 MAIN BEARING JOURNALS. THE #2 MAIN BEARING WAS SEVERELY FRAGMENTED AND DEFORMED, AND THE NUMBER 2 MAIN BEARING SADDLE WAS SEVERELY DEFORMED. A METALLURGICAL EXAMINATION OF THE CRANKSHAFT INDICATED THAT IT HAD FAILED FROM FATIGUE. THE EXAMINATION ALSO DISCLOSED THAT THE CRANKSHAFT CONFORMED TO THE MANUFACTURER'S MATERIAL SPECIFICATIONS FOR HARDNESS AND NITRIDING. RECORDS SHOWED THE ENGINE HAD BEEN REBUILT BY THE MANUFACTURER ON 7/23/92 AND INSTALLED IN THE AIRPLANE ON 9/3/92. AFTER BEING REBUILT, IT HAD ACCUMULATED 1154 HOURS OF FLIGHT TIME. AT 1004 HOURS, THE OIL PUMP HAD BEEN SERVICED DUE TO LOW OIL PRESSURE. DURING A 100 HOUR INSPECTION AT 1140 HOURS, METAL WAS FOUND IN THE OIL FILTER AND THE #4 CYLINDER WAS CHANGED.
Probable Cause: A FAILURE OF THE #2 MAIN ENGINE BEARING AND SUBSEQUENT FATIGUE FAILURE OF THE ENGINE CRANKSHAFT. A FACTOR RELATING TO THE ACCIDENT WAS: THE LACK OF SUITABLE TERRAIN FOR AN EMERGENCY LANDING.
Accident investigation:
|
| |
Investigating agency: | NTSB |
Report number: | ANC95LA058 |
Status: | Investigation completed |
Duration: | 8 months |
Download report: | Final report |
|
Sources:
NTSB ANC95LA058
Location
Revision history:
Date/time | Contributor | Updates |
14-Mar-2024 20:07 |
ASN Update Bot |
Added |
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