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| Date: | Sunday 4 April 1999 |
| Time: | 14:30 LT |
| Type: |  Cessna 180J Skywagon 6 |
| Owner/operator: | Bobby Graham |
| Registration: | N420SB |
| MSN: | 18052313 |
| Total airframe hrs: | 3990 hours |
| Engine model: | Continental O-470-R |
| Fatalities: | Fatalities: 0 / Occupants: 2 |
| Other fatalities: | 0 |
| Aircraft damage: | Substantial |
| Category: | Accident |
| Location: | Iliamna, AK -
 United States of America
|
| Phase: | Landing |
| Nature: | Private |
| Departure airport: | , AK |
| Palmer, AK (PAQ) | |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
The pilot was landing the wheel/ski equipped airplane on a frozen lake to wait for improving weather. During the landing roll, the pilot heard a 'whump' and the airplane settled onto the left wing. Inspection revealed the main landing gear attaching bolt had fractured in overload across a threaded area. The installed NAS-147R bolt was not the one specified for installation, and had a shorter smooth shank section (1.3 inches) than the specified AN bolt (1.43 inches). When an undamaged NAS-147R bolt is installed in the landing gear, a threaded area remains within the bolt hole. The bolt had been installed three weeks prior to the accident during the last annual inspection.
Probable Cause: The improper installation of the main landing gear attaching bolt by maintenance personnel, which resulted in total failure of the bolt and collapse of the landing gear.
Accident investigation:
 |
|
Sources:
NTSB ANC99LA042
History of this aircraft
Other occurrences involving this aircraft
| 7 September 1985 | N420SB | Private | 0 | Egegik, AK | |
sub |
| 1 October 1988 | N420SB | Graham, Bobby | 0 | Wasilla, AK | |
sub |
| 11 November 1988 | N420SB | Private | 0 | Meshik Lake, AK | |
sub |
| 12 June 1991 | N420SB | Bobby Graham | 0 | Pilot Point, AK | |
sub |
Location
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 26-Nov-2017 12:37 | ASN Update Bot | Added |
| 08-Apr-2024 07:42 | ASN Update Bot | Updated [Time, Operator, Other fatalities, Departure airport, Source, Narrative, Category, Accident report, ] |
Corrections or additions? ... Edit this accident description
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