Beechcraft B36TC N6465X

Summary

On 14 August 2011 at about 23:00 local time, a Beechcraft B36TC registered N6465X was involved in an accident near Lemoore, California, United States. 3 people were on board and nobody was injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

14 August 2011 at 23:00

Classification

Accident

Location

Lemoore, California, United States

Nearest airport

Lemoore Naval Air Station (NLC)

Coordinates

36.2897, -119.9375

Aircraft

Beechcraft B36TC

Registration

N6465X

Category

Airplane

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Bermuda Dunes → Byron

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR11LA380

Nobody was injured.

A loss of engine power during cruise flight due to maintenance personnel's failure to adequately torque the number 4 cylinder retaining nuts, which resulted in the in-flight separation of the cylinder.

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

Read the full NTSB narrative

The pilot reported that, while at cruise altitude, the engine experienced a partial loss of engine power. The pilot requested to land, and then heard a loud noise, followed by the engine cowling opening, and the pilot noted something fly out of the engine compartment followed by a total loss of engine power. Unable to reach the airport, the pilot subsequently made a forced landing in a plowed field. Postaccident examination of the engine revealed that the number 4 cylinder and piston had separated from the engine in flight and likely departed through the open engine cowling. The crankcase had mechanical damage concentrated at the number 4 and 6 cylinder bay areas. The number 4 cylinder bay area had missing crankcase material, with rubbed and displaced material noted on the cylinder attachment area. Further examination of the remaining cylinders found that the retaining self-locking nuts were loose and had not been tightened or properly torqued. Review of maintenance records noted that the engine had been overhauled less than 40 flight hours before the accident. It is likely that maintenance personnel did not properly tighten the self-locking nuts for the number 4 cylinder, which subsequently led to its separation.

Quoted verbatim from the NTSB record.