What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
On novemer 11, 1999, at 1300 EST, a delta flight #1749, had a tow bar separation during push back. As the a/c was ina transition mode from pushing to pulling, the shear pin on the tow bar snapped. The a/c then rolled forward into the tug and caused substantial damage to the right side of the fuselage before coming to rest. The crew and its passengers were not injured at the time of the accident. During the investigation, it was noted that all three engines were running at flight idle, and that the APU was inoperative at the time. It was also noted that delta has a provision in their a/c operating manual to start engines 1 and 3 at the gate if the APU is inoperative. However, on the side the delta ramp service manual, states that engines 1 and 2 are to be started at the gate if the APU is inoperative. Both manuals are in consistently with each other. In addition the above findings the preliminary evidence shows that stress cracks in the shear pin had existed prior to the event.
As the FAA filed it
ON NOVEMER 11, 1999, AT 1300 EST, A DELTA FLIGHT #1749, HAD A TOW BAR SEPARATION DURING PUSH BACK. AS THE A/C WAS INA TRANSITION MODE FROM PUSHING TO PULLING, THE SHEAR PIN ON THE TOW BAR SNAPPED. THE A/C THEN ROLLED FORWARD INTO THE TUG AND CAUSED SUBSTANTIAL DAMAGE TO THE RIGHT SIDE OF THE FUSELAGE BEFORE COMING TO REST. THE CREW AND ITS PASSENGERS WERE NOT INJURED AT THE TIME OF THE ACCIDENT. DURING THE INVESTIGATION, IT WAS NOTED THAT ALL THREE ENGINES WERE RUNNING AT FLIGHT IDLE, AND THAT THE APU WAS INOPERATIVE AT THE TIME. IT WAS ALSO NOTED THAT DELTA HAS A PROVISION IN THEIR A/C OPERATING MANUAL TO START ENGINES 1 AND 3 AT THE GATE IF THE APU IS INOPERATIVE. HOWEVER, ON THE SIDE THE DELTA RAMP SERVICE MANUAL, STATES THAT ENGINES 1 AND 2 ARE TO BE STARTED AT THE GATE IF THE APU IS INOPERATIVE. BOTH MANUALS ARE IN CONSISTENTLY WITH EACH OTHER. IN ADDITION THE ABOVE FINDINGS THE PRELIMINARY EVIDENCE SHOWS THAT STRESS CRACKS IN THE SHEAR PIN HAD EXISTED PRIOR TO THE EVENT.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.
Other reports on N521DA · 3
Matched to the same aircraft by N-number and date.