Casualties unknown

1990-07-25: Lake LA-4-200 (N8011M) — Paul E. Thorn — Gt. Barrington, MA

Gt. Barrington, MA, US

On July 25, 1990, a Lake LA-4-200 (registration N8011M) operated by Paul E. Thorn was involved in an aviation accident near Gt. Barrington, MA. Investigators recorded the probable cause as: The engine was not capable of producing rated power due to mechanical inefficiency and wear limits being exceeded. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 1781061362Data APIEditorial standards

After takeoff, aircraft climbed to 50 ft; pilot lowered nose twice to accelerate, losing altitude each time. Banked right, struck trees 1,500 ft from runway, impacted in backyard. Passenger escaped; pilot not rescued before fire. Engine exam found corrosion, worn parts, timing error; engine incapable of rated power due to inefficiency and wear.

Accident Sequence

Following takeoff, the aircraft climbed to approximately 50 feet above ground level. The pilot attempted to accelerate by lowering the nose on two occasions, each time resulting in a loss of altitude. Subsequently, the aircraft banked to the right and collided with trees about 1,500 feet from the runway departure end. Impact occurred within a residential backyard. The passenger managed to escape the wreckage but was unable to rescue the pilot before fire engulfed the cabin.

Engine Findings

A post-accident engine run was performed and proved successful; however, it failed to achieve the required airflow and RPM test points. Disassembly of the engine disclosed corrosion throughout the components, indicating prolonged periods of inactivity. Evidence of multiple worn parts and metal contamination was also present. Compression readings for cylinders 1 through 4 were 65/80, 75/80, and 69/80, respectively. The left magneto timing was measured at 24.5 degrees before top center, compared to the specified timing of 20 degrees before top center.

Maintenance History

An annual inspection had been completed on April 5, 1990. The investigation determined that the engine was not capable of producing rated power due to mechanical inefficiency and because wear limits had been exceeded.

Probable cause

The engine was not capable of producing rated power due to mechanical inefficiency and wear limits being exceeded.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001212X23780. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.