What happened
On December 1, 1959, an Allegheny Airlines flight consisting of a Convair 340 (implied by context/type) was performing a scheduled service from Philadelphia to Cleveland with several intermediate stops. After departing Philadelphia as a VFR flight, the aircraft stopped in Harrisburg to exchange passengers and cargo before continuing toward Williamsport.
While navigating near Williamsport, the crew requested instrument clearance. During the approach phase, the aircraft was operating under visual flight rules despite deteriorating weather conditions involving light snow and low ceilings. At approximately 0941, the flight reported being on final approach, receiving updates regarding surface winds and runway lighting.
Following an initial pass over the airport that was too high for landing, the pilot attempted a circling approach to runway 27. During this maneuver, the aircraft transitioned from a right turn into a left turn, heading south. Observers noted the plane disappeared into snow-filled clouds at an altitude of roughly 400 feet. Shortly thereafter, an explosive sound was heard. The wreckage was later located on Bald Eagle Mountain at an elevation of 1,150 feet.
The accident resulted in 24 fatalities, including the crew and 21 of the 22 passengers on board. The aircraft was destroyed upon impact.
Findings
Investigators determined that the primary reason for the crash was the pilot's failure to properly abandon the approach in a timely manner. Additionally, it was noted as a likely contributing factor that the fluxgate compass may have become accidentally caged, leading to an incorrect heading indication during the maneuver.