ASN Aircraft accident Martin 4-0-4 N40403 Pittsburgh-Greater Pittsburgh Airport, PA (PIT)
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Status:Accident investigation report completed and information captured
Date:Sunday 1 April 1956
Type:Silhouette image of generic M404 model; specific model in this crash may look slightly different
Martin 4-0-4
Operator:Trans World Airlines - TWA
Registration: N40403
MSN: 14103
First flight: 1951
Total airframe hrs:9177
Crew:Fatalities: 1 / Occupants: 3
Passengers:Fatalities: 21 / Occupants: 33
Total:Fatalities: 22 / Occupants: 36
Aircraft damage: Damaged beyond repair
Location:0,5 km (0.3 mls) SW of Pittsburgh-Greater Pittsburgh Airport, PA (PIT) (   United States of America)
Phase: Initial climb (ICL)
Nature:Domestic Scheduled Passenger
Departure airport:Pittsburgh-Greater Pittsburgh Airport, PA (PIT/KPIT), United States of America
Destination airport:Newark International Airport, NJ (EWR/KEWR), United States of America
TWA Martin 4-0-4 N40403 took off from Pittsburgh for an IFR flight to Newark. The first officer was in the left seat, being line-checked by a captain. After becoming airborne from runway 23, a sharp yaw was experienced while the first officer reduced power at an altitude of about 100 feet. Almost simultaneously the no. 1 zone fire warning light for the left engine illuminated; the fire bell didn't ring. The first officer then presumably moved the no. 1 throttle rearward intuitively. The captain didn't see the fire warning light and only noted the power loss indicated by the BMEP gauge. He then pulled the mixture to idle cut-off. The first officer reached for the manual feathering button but the captain informed him that the automatic feathering device would cause the no. 1 prop to feather. This did not happen however, because the throttle had been retarded aft of the switches that armed the autofeather system. The aircraft continued to yaw to the left due to the drag of the no. 1 prop until it struck the ground 1690 feet past the end of the runway.
It appeared that the fire warning was the result of the failure of an exhaust connector clamp which allowed heat exhaust gasses to impinge an overheat detector.

Probable Cause:

PROBABLE CAUSE: "Uncoordinated emergency action in the very short time available to the crew, which produced an aircraft configuration with insurmountable drag."

Accident investigation:

Investigating agency: CAB
Status: Investigation completed
Accident number: final report
Download report: Final report

» ICAO Accident Digest No.8, Circular 54-AN/49 (67-71)


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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 Pittsburgh-Greater Pittsburgh Airport, PA to Newark International Airport, NJ as the crow flies is 509 km (318 miles).
Accident location: Approximate; accuracy within a few kilometers.

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.
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Martin 4-0-4

  • 101 built
  • 3rd loss
  • 2nd fatal accident
  • The worst accident (at the time)
  • 2nd worst accident (currently)
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