Beechcraft M35 N9886R

Summary

On 21 November 1995 at about 14:56 local time, a Beechcraft M35 registered N9886R was involved in an accident near Estancia, New Mexico, United States. 3 people were on board and 2 had minor injuries. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

21 November 1995 at 14:56

Classification

Accident

Location

Estancia, New Mexico, United States

Coordinates

34.7608, -106.0607

Aircraft

Beechcraft M35

Registration

N9886R

Category

Airplane

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Business

Phase of flight

Not recorded

Route

Albuquerque → Carlsbad

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

FTW96LA050

2 people had minor injuries.

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.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

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.

Quoted verbatim from the NTSB record.