ASN Wikibase Occurrence # 157770
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| Date: | Wednesday 24 July 2013 |
| Time: | 11:40 |
| Type: |  de Havilland Canada DHC-2 Beaver |
| Owner/operator: | Promech Air |
| Registration: | N4787C |
| MSN: | 1330 |
| Year of manufacture: | 1958 |
| Total airframe hrs: | 33326 hours |
| Engine model: | Pratt & Whitney R-985AN-14B |
| Fatalities: | Fatalities: 0 / Occupants: 4 |
| Aircraft damage: | Substantial |
| Category: | Accident |
| Location: | near Lake Galea, Prince of Wales island, AK -
 United States of America
|
| Phase: | Landing |
| Nature: | Unknown |
| Departure airport: | Ketchikan, AK (5KE) |
| Shipley Bay, AK | |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
The pilot reported that, while the float-equipped airplane was in cruise flight about 1,200 ft above ground level, the engine made a loud noise and lost partial power, so he maneuvered the airplane to land on a nearby lake. During the approach, the engine lost total power, and the airplane descended into an area of trees before reaching the lake, which resulted in substantial damage to the wings, fuselage, and empennage.
The operator reported that the engine had been overhauled (zero-timed) 31 hours before the accident. A postaccident engine examination revealed metal fragments and heavy gouging damage to the rotating components within the crankcase. The bottom portion (crankshaft end) of the No. 1 linkrod and its respective bushing were missing from the No. 1 linkpin; the oil sump contained metal debris consistent with heavily damaged remnants of these (and other) components. The No. 2 cylinder barrel and linkrod and the No. 3 linkrod showed deformation to the left (in the direction of engine rotation). Based on the damage observed in the engine, it is likely that the event that initiated the engine failure involved either the the No. 1 linkrod bushing or the bottom portion of the No. 1 linkrod; however, the extensive damage to these components precluded determination of the failure mode.
Probable Cause: The failure of the No. 1 linkrod bushing or the bottom portion of the linkrod, which resulted in a total loss of engine power.
Accident investigation:
 |
|
Sources:
NTSB
History of this aircraft
Other occurrences involving this aircraft
| 26 July 1984 | N4787C | Promech Air | 2 | Ketchikan, AK | |
w/o |
| 29 September 1997 | N4787C | Promech Air, Inc. | 1 | Ketchikan, Alaska | |
w/o |
Location
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 25-Jul-2013 04:20 | Geno | Added |
| 25-Jul-2013 07:32 | harro | Updated [Aircraft type] |
| 25-Jul-2013 22:40 | Geno | Updated [Registration, Cn, Source, Narrative] |
| 31-Jul-2013 13:03 | TB | Updated [Aircraft type, Location] |
| 21-Dec-2016 19:28 | ASN Update Bot | Updated [Time, Damage, Category, Investigating agency] |
| 18-Aug-2017 17:54 | ASN Update Bot | Updated [Other fatalities, Nature, Departure airport, Destination airport, Source, Narrative] |
Corrections or additions? ... Edit this accident description
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