Investigation Summary
The flight was conducting a VOR/DME approach to runway 32 at Bradford during night instrument meteorological conditions. The NTSB investigation revealed that the flight was executed correctly until the aircraft reached the 2.9-mile DME fix. At this point, the crew was required to maintain a Minimum Descent Altitude (MDA) of 2,543 feet until the runway environment was in sight. Instead, the aircraft continued a steady descent. Cockpit voice recordings indicated that both the Captain and First Officer were preoccupied with looking out the windows for the ground or runway lights, neglecting to monitor the altimeter. A small navigational error placed the aircraft slightly off the intended approach path, and a localized, rapid deterioration in visibility meant the crew was flying into much worse conditions than the one-mile visibility reported by the airport. The First Officer realized the proximity to the ground only seconds before impact, shouting for a pull-up, but the aircraft struck a large tree and flipped over.
Final Conclusions
The NTSB determined the probable cause was the continuation of the descent through the Minimum Descent Altitude and into obstructing terrain while both crewmembers were looking outside the aircraft. Contributing factors included minimal visual references available at night, a small navigational error during the final approach stages, and a rapid change in visibility that was unknown to the crew.
Video Analysis
The Christmas Eve Crash: Allegheny Airlines Flight 736 — A detailed look at the 1968 crash of Allegheny Flight 736 and the subsequent crash of Flight 737 at the same airport just weeks later.
If playback is blocked, the owner has disabled embedding — use the link above.
Airframe & Maintenance
Crew Experience
Captain
Gary Lee Mull, aged 33.
First Officer
Richard Bruce Gardner, aged 30.
Systems & Failure Modes
VOR/DME Approach
A non-precision approach relying on a Very High Frequency Omnidirectional Range station and Distance Measuring Equipment. It provides lateral guidance and distance but no vertical glide path.
Allison 501-D13
The turboprop engines installed during the aircraft's conversion to a CV-580, providing significantly more power than the original piston engines.
Interesting Facts
- 01The aircraft was originally a Convair CV-440 built in 1957 (MSN 410) and converted to a CV-580 in 1965.
- 02The crash site was located less than a mile northwest of the Kinzua Bridge.
- 03Survivors used seat cushions and luggage to build a bonfire to stay warm and signal rescuers in the snowstorm.
- 04The aircraft first contacted trees at an altitude 462 feet below the mandated Minimum Descent Altitude (MDA).
- 05Just 13 days later, Allegheny Airlines Flight 737 crashed while approaching the same airport from the opposite direction.
Safety Actions & Advisories
Allegheny Airlines Visibility Rules
Source ↗Following this crash and the crash of Flight 737, Allegheny self-imposed rules requiring a 1,000-foot ceiling and 3-mile horizontal visibility for landings at any airport without an Instrument Landing System (ILS).