Narrative:Allegheny Airlines Flight 121, a Douglas DC-9-31, suffered a landing accident on the Philadelphia International Airport, Pennsylvania. Of the 106 persons onboard, 86 persons were injured; there were no fatalities.
The captain of Flight 121 had conducted an instrument approach to runway 27R in visual conditions as a thunderstorm passed over the airport in a north-northeasterly direction. When near the threshold the captain initiated a go-around from a low altitude and entered rain of increasing intensity. Shortly thereafter the aircraft was seen descending in a noseup attitude with the landing gear retracted. After striking tail first on a taxiway about 4,000 feet beyond the threshold of runway 27, the aircraft slid about 2,000 feet and stopped. The wreckage came to rest about 6000 feet beyond the threshold and about 350 feet to the right of the centerline of runway 27R.
Probable Cause:
PROBABLE CAUSE: "The aircraft's encounter with severe horizontal and vertical wind shears near the ground as a result of the captain's continued approach into a clearly marginal severe weather condition. The aircraft's ability to cope under these conditions was borderline when flown according to standard operating procedures; however, if the aircraft's full aerodynamic and power capability had been used, the wind shear could probably have been flown through successfully. Contributing to the accident was the tower controller's failure to provide timely below-minimum RVR information."
Accident investigation:
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Investigating agency: | NTSB  |
Status: | Investigation completed |
Duration: | 1 year and 7 months | Accident number: | NTSB/AAR-78-02 | Download report: | Final report
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Sources:
» ICAO Circular 146-AN/96 (148-161)
» NTSB-AAR-78-2
Follow-up / safety actions
NTSB issued 1 Safety Recommendation
Issued: 02-FEB-1978 | To: | A-78-3 |
ESTABLISH A JOINT GOVERNMENT - INDUSTRY COMMITTEE TO DEVELOP FLIGHT TECHNIQUES FOR COPING WITH INADVERTENT ENCOUNTERS WITH SEVERE WIND SHEARS AT LOW ALTITUDE. (Closed - Acceptable Action) |
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Photos

accident date:
23-06-1976type: McDonnell Douglas DC-9-31
registration: N994VJ

accident date:
23-06-1976type: McDonnell Douglas DC-9-31
registration: N994VJ
Map
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 Windsor Locks-Bradley International Airport, CT to Philadelphia International Airport, PA as the crow flies is 312 km (195 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.