Crash of a BAc 111-204AF in Blossburg: 34 killed

Date & Time: Jun 23, 1967 at 1447 LT
Type of aircraft:
Operator:
Registration:
N1116J
Flight Phase:
Survivors:
No
Schedule:
Elmira - Washington DC
MSN:
98
YOM:
1966
Flight number:
MO040
Crew on board:
4
Crew fatalities:
Pax on board:
30
Pax fatalities:
Other fatalities:
Total fatalities:
34
Captain / Total flying hours:
13875
Captain / Total hours on type:
603.00
Copilot / Total flying hours:
4814
Copilot / Total hours on type:
677
Aircraft flight hours:
2246
Circumstances:
The aircraft departed Elmira-Corning Airport at 1439LT on a schedule flight to Washington-National Airport, carrying 30 passengers and a crew of four. After takeoff, the crew was cleared to climb to FL160 when the airplane went into a nose-down attitude, plunged into the earth and crashed in a huge explosion in a wooded area located one mile east of Blossburg, Pennsylvania. The aircraft disintegrated on impact and none of the 34 occupants survived the crash.
Probable cause:
The loss of integrity of empennage pitch control systems due to a destructive in-flight fire which originated in the airframe plenum chamber, fueled by hydraulic fluid, progressed up into the vertical tail fin. The fire resulted from engine bleed air flowing back through the malfunctioning non return valve and an open air delivery valve, through the auxiliary power unit in a reverse direction, and exiting into the plenum chamber at temperatures sufficiently high to cause the acoustics linings to ignite.
Final Report: