ASN Wikibase Occurrence # 174017
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Date: | Saturday 17 January 2004 |
Time: | 15:25 |
Type: | Cessna 170B |
Owner/operator: | Private |
Registration: | N2502C |
MSN: | 26146 |
Total airframe hrs: | 5228 hours |
Fatalities: | Fatalities: 0 / Occupants: 1 |
Aircraft damage: | Substantial |
Category: | Accident |
Location: | Santa Rosa, CA -
United States of America
|
Phase: | Landing |
Nature: | Private |
Departure airport: | Santa Rosa, CA (STS) |
Destination airport: | |
Investigating agency: | NTSB |
Confidence Rating: | Accident investigation report completed and information captured |
Narrative:The engine lost power and the airplane nosed over during a forced landing in a field. Post accident examination revealed that the number 2 cylinder separated from the engine. The engine had accumulated 900 hours since its last major overhaul 13 years prior to the accident; the cylinder had accumulated 1,212 hours since replacement in 1986. The hours on the cylinder prior to that time could not be determined. A metallurgical examination found that the barrel failed due to a fatigue crack. The barrel fractured circumferentially between the 11th and 13th fin from the head. The fracture initiated approximately 1.8 inches below the head and started from the inner diameter below a plated region. The initiation area was a small, flat, thumbnail-shaped region approximately 0.5-inch wide through the wall thickness, with signatures indicative of fatigue. Multiple crack initiation sites were observed in the origin area. From the initiation point, the fracture continued propagating in the circumferential direction with coarse arrest marks over approximately 45 percent of the barrel circumference. No material, manufacture, or plating defects were found. The metallurgical examination could not determine why the cracking occurred at the given location; however, it occurred below the chrome plating. From this, it is possible that the barrel exhausted the available fatigue life at that location, which was lowered by the presence of plating.
Probable Cause: the failure of the number 2 cylinder barrel due to fatigue. The lack of suitable landing terrain was a factor in the accident.
Sources:
NTSB:
https://www.ntsb.gov/_layouts/ntsb.aviation/brief.aspx?ev_id=20040126X00110&key=1 Location
Revision history:
Date/time | Contributor | Updates |
21-Feb-2015 18:27 |
Noro |
Added |
21-Dec-2016 19:28 |
ASN Update Bot |
Updated [Time, Damage, Category, Investigating agency] |
07-Dec-2017 17:34 |
ASN Update Bot |
Updated [Total occupants, Other fatalities, Departure airport, Destination airport, Source, Narrative] |
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