What happened
On a scheduled service from Elmira-Corning Airport to Washington-National Airport, an aircraft carrying 30 passengers and four crew members experienced a catastrophic failure shortly after departure. At approximately 14:39 local time, the flight crew received clearance to climb to FL160. During this ascent, the aircraft type entered a sudden nose-down pitch.
The plane descended rapidly into a forested region situated roughly one mile east of Blossburg, Pennsylvania. The impact was followed by a massive explosion, and the airframe disintegrated upon hitting the ground. There were 34 fatalities and no survivors from the crash.
Findings
Investigations determined that an intense in-flight fire destroyed the pitch control systems within the empennage. This fire began in the airframe plenum chamber, where it was fueled by hydraulic fluid before spreading into the vertical tail fin. The ignition was triggered when engine bleed air escaped through a malfunctioning non-return valve and an open air delivery valve. This air traveled in reverse through the auxiliary power unit and exited into the plenum chamber at temperatures high enough to ignite the acoustic linings.