Unfallbericht:Allegheny Flight 371 was scheduled between Philadelphia, PA, and Cleveland, OH with stops at Harrisburg (HAR), Williamsport (IPT), Bradford, and Erie. Flight 371 departed Philadelphia at 08:15, proceeded VFR to Harrisburg where it landed at 08:5l without incident. Flight 371 departed Harrisburg at 09:06 with 22 revenue passengers, one additional crew member9 and 598 pounds of baggage, mail, and cargo.
|Datum:||Dienstag 1 Dezember 1959|
|Triebwerk:|| 2 Pratt & Whitney R-2800-77|
|Besatzung:||Todesopfer: 4 / Insassen: 4|
|Fluggäste:||Todesopfer: 21 / Insassen: 22|
|Gesamt:||Todesopfer: 25 / Insassen: 26 |
|Konsequenzen:|| Written off (damaged beyond repair)|
|Unfallort:||2,1 km (1.3 Meilen) S of Williamsport-Lycoming County Airport, PA (IPT) ( USA)
|Flugphase:|| Annäherung (APR)|
|Betriebsart:||Inländischer planmäßiger Passagierflug|
|Flug von:||Harrisburg-Capital Landing Field, PA (HAR/KCXY), USA|
|Flug nach:||Williamsport-Lycoming County Airport, PA (IPT/KIPT), USA|
At 09:23 Flight 371 reported to Williamsport radio that it was making 360-degree turns five minutes south of the Williamsport low frequency range at an altitude of 3,500 feet, VFR and requested an instrument clearance to the
Williamsport Airport. Williamsport radio responded by giving the 09:17 Williamsport weather observation, which was: Precipitation ceiling 1,000 feet, sky obscured; visibility one mile in light snow, wind west at five knots; altimeter 30.26 At this time Williamsport radio requested that the flight stand by for clearance At 09:27 Flight 371 was cleared direct to the Williamsport low frequency range from its present position, to maintain 4,000 feet.
At 09:33 Flight 371 was cleared for an approach to the Williamsport Airport, to report on the ground, or cancelling IFR. At this time Flight 371 reported over the Williamsport low frequency range, leaving 4,000 feet, and commencing an approach At 09:35 the Williamsport 09:34 weather observation was given as being 1,000-feet scattered, precipitation observation 7,000 feet; visibility 1-1/2 miles in light snow, wind west at four knots, altimeter setting 30.26 inches. Allegheny minimums for this approach to the Williamsport Airport are 900 feet ceiling and 1-1/2 miles visibility.
At 09:41 Flight 371 reported over the low frequency range on final approach. At this time the flight was advised of the surface wind, altimeter setting, and that the runway lights were on high brilliancy on runway 9-27. Flight 371 acknowledged all of these transmissions from Williamsport radio. At 09:42 the flight reported in range to the company on company frequency. At this time the company advised that their altimeter setting was 30.25 inches and requested the arrival and departure times of the flight at Harrisburg. Flight 371 acknowledged the altimeter setting but did not relay the time information requested.
It is believed that during the base leg the captain relied on the MDI of the fluxgate compass owing to the weather and cockpit visibility restrictions that existed. The fluxgate compass caging switch, located on the back of the pedestal, was probably accidentally actuated by the foot of the crew member occupying the jump seat during the initial part of the base leg.
The captain continued his turn intending to roll out on the runway heading but reference to the MDI indicated that he had overshot his heading so he immediately turned to the left to an indicated heading of 270 degrees After rolling out on this heading he was unable to see the field which was now to his right and he continued on for a few seconds expecting to see the field momentarily. Owing to the induced error of approximately 80 degrees to the right the aircraft was now on an actual heading of approximately 190 degrees and the heading for Bald Eagle Mountain. The aircraft then encountered snow showers and clouds. The captain continued his flight on the indicated heading of 270 degrees for approximately 12 to 14 seconds, during which the aircraft was converging with the northern slope of Bald Eagle Mountain. During this time the captain noted the discrepancy between the MDI and his other directional instruments and caged the fluxgate compass in an effort to determine his correct heading. Upon completion of the caging cycle the MDI turned to a heading of approximately 190 degrees. At this time, just prior to the crash, the aircraft was turned to the right, full throttle was applied, and gear retraction was initiated. Before this turn could be completed the aircraft crashed into the trees and rocky terrain of the mountain at an elevation of 1,150 msl. Most of the passenger cabin area was consumed by the ground fire which followed the crash.
Probable Cause:PROBABLE CAUSE: "The captain's failure to execute a timely abandoned approach. The probable accidental caging of the fluxgate compass, which would have resulted in an erroneous heading indication, is considered to be a likely contributing factor."
» ICAO Accident Digest, Circular 62-AN/57 (219-226)
This map shows the airport of departure and the intended destination of the flight. The line between the airports does not
display the exact flight path.
Distance from Harrisburg-Capital Landing Field, PA to Williamsport-Lycoming County Airport, PA as the crow flies is 113 km (71 miles).
This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.