Fatal aircraft crash near Mercer during cargo flight

2 fatalities • Mercer, United States of America • Flight

A twin-engine cargo aircraft crashed in a cornfield near Mercer following an in-flight fire and explosion.

What happened

During a scheduled cargo transport from Buffalo to Beaver Falls, a twin engine airplane experienced a significant fire and subsequent explosion while maintaining cruising altitude. The incident forced the aircraft to descend rapidly, ultimately resulting in a crash into a cornfield situated near Mercer. The impact of the crash caused the total destruction of the airframe.

There were two fatalities among the crew members on board the aircraft during the accident.

Findings

Investigations into the wreckage identified several critical mechanical failures that led to the disaster. A fatigue fracture occurred within the exhaust system manifold, specifically involving part number 085072-39. This crack, measuring approximately three inches, allowed hot exhaust gases to escape into the wing structure.

This leak of high-temperature gas ignited a pre-existing leak in the fuel system, where lines and fittings were found to be leaking. The resulting fire within the wing was exacerbated by excessive temperatures and the presence of high obstructions. The primary cause of the accident was determined to be an inadequate aircraft inspection by maintenance staff, which allowed these critical component failures to go undetected.

Probable cause

The in-flight fire was caused by a fatigue crack in the exhaust manifold that allowed hot gases to ignite leaking fuel components due to improper maintenance inspections.

Frequently asked questions

What happened in the 1977-09-28 Cessna 402 accident near Mercer, United States of America?

A twin-engine cargo aircraft crashed in a cornfield near Mercer following an in-flight fire and explosion.

Were there any fatalities in the 1977-09-28 Cessna 402 accident?

The accident was fatal, resulting in 2 fatalities.

What aircraft was involved and where did it happen?

The accident on 1977-09-28 involved a Cessna 402, registration N69338, operated by Sky Line Flying Services, at Mercer, United States of America.

What was the probable cause of the accident?

The in-flight fire was caused by a fatigue crack in the exhaust manifold that allowed hot gases to ignite leaking fuel components due to improper maintenance inspections.

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