Casualties unknown

1987-06-28: American Aviation Corp. (aac) AA-1A (N9399L) — Kralltown, PA

Kralltown, PA, US

On June 28, 1987, an American Aviation Corp. (aac) AA-1A (registration N9399L) was involved in an aviation accident near Kralltown, PA. Investigators recorded the probable cause as: The pilot's failure to achieve adequate climb performance during takeoff from a short grass runway in hot and humid conditions, resulting in collision with terrain, followed by fire caused by sparks igniting leaking fuel during post-impact battery disconnect. 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

Aircraft failed to climb after takeoff from a short grass runway on a hot day, striking trees. Subsequent battery disconnection ignited fuel leaks, causing further fire damage.

What happened

The pilot attempted to take off from a 2130-foot grass strip under relatively hot and humid conditions, with an air temperature of 85 degrees Fahrenheit. Approximately two-thirds of the way down the runway, he rotated the aircraft for takeoff. However, it did not climb sufficiently to clear a hill located beyond the airport boundary.

The aircraft subsequently touched down and ran into trees, resulting in substantial damage. About one and a half hours later, the operator arrived at the aircraft. While disconnecting the battery, sparks ignited leaking fuel, causing further damage by fire.

The investigation

The investigation focused on the mechanical condition of the aircraft and the circumstances surrounding the incident. The initial impact with trees caused substantial damage to the airframe. Subsequent examination revealed that fuel was leaking from the aircraft. When the operator attempted to disconnect the battery, electrical sparks ignited this fuel, leading to a fire that further damaged the aircraft.

Findings

Several factors contributed to the outcome of this incident. The short length of the grass runway likely limited acceleration and climb performance. High ambient temperatures reduce air density, which can degrade engine power and lift generation. The pilot's decision to rotate at that point did not result in adequate climb gradient to clear the terrain obstacle.

Additionally, the presence of leaking fuel created a hazardous environment after the initial crash. The act of disconnecting the battery introduced an ignition source in close proximity to the fuel vapor, exacerbating the damage through fire.

Probable cause

The pilot's failure to achieve adequate climb performance during takeoff from a short grass runway in hot and humid conditions, resulting in collision with terrain, followed by fire caused by sparks igniting leaking fuel during post-impact battery disconnect.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001213X31325. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.