Beechcraft A36 N920GL

Summary

On 29 December 2004 at about 23:35 local time, a Beechcraft A36 registered N920GL was involved in an incident near Natchitoches, Louisiana, United States. 4 people were on board and nobody was injured. The aircraft was slightly damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

29 December 2004 at 23:35

Classification

Incident

Location

Natchitoches, Louisiana, United States

Coordinates

31.7356, -93.0989

Aircraft

Beechcraft A36

Registration

N920GL

Category

Airplane

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Diamondhead → Center

Aircraft damage

Minor

Weather

VMC

Light

Day

NTSB number

DFW05IA048

Nobody was injured.

The loss of engine power due to pre-ignition and detonation. Contributing factors were the lack of suitable terrain available for the forced landing and the unapproved installation of a turbocharger.

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

Read the full NTSB narrative

The 15,000-hour commercial pilot reported that while he was in cruise flight at 12,000 feet mean sea level (msl) during an IFR cross country flight, he began to smell smoke and noticed the engine began to surge. After requesting a lower altitude, the air traffic controller advised him of the nearest airport. During the descent, at an altitude of approximately 9,000 feet msl, "the engine lost oil pressure" and the pilot shut the engine down using the mixture control. The "engine continued to turn over" as he heard "several loud explosions and observed fireballs at the propeller hub" before the propeller stopped turning. After realizing he was unable to make it to the airport, the pilot elected to land in a field approximately 1/2 mile south of his intended airport. After maneuvering the airplane under a set of power lines, the pilot landed in an open field. A detailed examination of the engine was completed at the facilities of the engine manufacturer. The examination revealed that the crankshaft and counterweights assembly exhibited lubrication distress of a varying degree to all connecting rod journals and bearings. The number six piston head exhibited detonation and pre-ignition damage. The examination concluded that a turbo-normalizing system had been installed and the installation of a turbo-normalizing system on an engine originally certificated as a normally aspirated model containing high compression pistons is contrary to the recommendations in TCM Service Bulletin M64-18 and can reduce the engine's detonation margins.

Quoted verbatim from the NTSB record.