ASN Wikibase Occurrence # 299018
This information is added by users of ASN. Neither ASN nor the Flight Safety Foundation are responsible for the completeness or correctness of this information.
If you feel this information is incomplete or incorrect, you can submit corrected information.
| Date: | Tuesday 9 May 2000 |
| Time: | 12:40 LT |
| Type: |  Beechcraft B24R |
| Owner/operator: | Flight Safety Alaska |
| Registration: | N6951R |
| MSN: | MC-316 |
| Total airframe hrs: | 7137 hours |
| Engine model: | Lycoming IO-360A1B6 |
| Fatalities: | Fatalities: 0 / Occupants: 2 |
| Aircraft damage: | Substantial |
| Category: | Accident |
| Location: | ANCHORAGE, Alaska -
 United States of America
|
| Phase: | Unknown |
| Nature: | Training |
| Departure airport: | |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
The first pilot, a certificated flight instructor, was providing flight instruction to the second pilot, a certificated private pilot. While returning to the airport, during the initial descent, the engine began to run rough, and lose power. The roughness improved momentarily, followed by a severe engine vibration, a loud bang, and complete loss of engine power. During a forced landing in a densely populated neighborhood, the airplane struck a power line, veered to the right, collided with the street, and came to rest in the front yard of a daycare center. Examination of the engine revealed the number 3 cylinder was broken free at the crankcase-mounting flange. A metallurgical examination of the number 4 position crankcase thru-bolt showed signs of fatigue cracking that emanated from the thread root. In addition, the cylinder flange mating surface displayed signs of fretting damage consistent with relative movement between the cylinder and the crankcase. The operator's director of maintenance stated that about 40 hours before the accident, he repaired a substantial oil leak between the number 3 cylinder, and the engine crankcase. He said that in the process of the repair he removed the number 4 position crankcase thru-bolt nut, applied an engine sealant, reinstalled the through bolt nut, and torqued the nut in accordance with the Lycoming overhaul manual. There was no engine log book entry pertaining to the engine total time, aircraft total time, or date when this repair was accomplished.
Probable Cause: A fatigue failure of the crankcase through bolt, the separation of number 3 cylinder assembly, and the inadequate maintenance/service of the airplane by company maintenance personnel.
Accident investigation:
 |
|
Sources:
NTSB ANC00FA056
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 16-Oct-2022 01:30 | ASN Update Bot | Added |
Corrections or additions? ... Edit this accident description
The Aviation Safety Network is an exclusive service provided by:
Quick Links:
| ASN Home | Send Correction / Feedback |
| FSF Home | Disclaimer | Copyright |
| Contact Us | Privacy Policy |
| Press / Media |
CONNECT WITH US:
©2024 Flight Safety Foundation