ASN Wikibase Occurrence # 357999
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| Date: | Tuesday 21 November 1995 |
| Time: | 08:56 LT |
| Type: |  Beechcraft M35 |
| Owner/operator: | Private |
| Registration: | N9886R |
| MSN: | D-6457 |
| Year of manufacture: | 1960 |
| Total airframe hrs: | 5888 hours |
| Engine model: | Continental IO-470-C |
| Fatalities: | Fatalities: 0 / Occupants: 3 |
| Aircraft damage: | Substantial |
| Category: | Accident |
| Location: | Estancia, NM -
 United States of America
|
| Phase: | En route |
| Nature: | Executive |
| Departure airport: | Albuquerque, NM |
| Carlsbad, NM (KCNM) | |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
While cruising at 9,500 feet MSL, the pilot noticed 'vibrations' accompanied by a 'slight' loss of power. He then 'heard a loud noise,' observed smoke, and the engine lost 'all power.' Subsequently, the airplane collided with trees during a forced landing on wooded/mountainous terrain. Engine examination revealed the following: A hole, 3 inches in diameter, was found adjacent to the #1 cylinder's attachment point on the right side of the crankcase. Debris from the #1 and #2 pistons and the #1 and #2 connecting rods was found throughout the interior of the crankcase. According to an FAA inspector's report, 'Cylinders 1 and 2 evidenced a catastrophic failure similar to that caused by detonation from uneven fuel distribution.' The rear crankcase journals were dry and displayed thermal damage. The interior of the crankcase and rear section of the crankshaft displayed impact damage associated with internal engine component failures. Part of an air intake bypass door from the throttle body air intake was found lodged in the intake port of the #6 cylinder. Examination of the throttle body revealed that a replacement air intake door had been installed, but maintenance records did not reveal service performed on (or a replacement of) the bypass door.
Probable Cause: improper maintenance and inspection of the engine, ingestion of an air intake bypass door into the engine intake, detonation (or preignition), and failure of the #1 and #2 piston and connecting rod assemblies. A factor relating to the accident was: the lack of suitable terrain for a forced landing.
Accident investigation:
 |
|
Sources:
NTSB FTW96LA050
Location
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 14-Mar-2024 08:59 | ASN Update Bot | Added |
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