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Special Reports: Delta Air Lines Flight 1141

By: Chris Kilroy and Per Axelsson

The Cover of The Dallas Times Herald the morning after the crash of Delta 1141.
The morning of August 31, 1988 in the Dallas/Ft. Worth metroplex was a beautiful one. The temperature was hovering near 75°, with a light south-westerly wind and unlimited visibility. At gate 31 in terminal 3E at the Dallas/Ft. Worth International Airport, Delta Air Lines Boeing 727-232 N473DA was being prepared for the morning flight to Salt lake City.

Coming on board the aircraft, which began boarding at 7:55am local time, were 102 SLC-bound passengers, three flight attendants, and the three person flight crew. At 8:10am, all were seated, and the aircraft was cleared to push from the gate. After completing the engine start sequence, Flight 1141 called ground and requested to "taxi from spot niner with alpha for departure." 1141 was advised that "the (runway) 17's are pretty well backed up, if you can take 18L we'll be able to get you out quicker." The crew chose to accept runway 18L for departure, and was given instructions to taxi to the runway via the "alpha bridge."

DFW Airport is built on a large section of land between the cities of Dallas and Ft. Worth. Running through the center of the metroplex is a six-lane highway, and to facilitate aircraft operations from one side of the field to the other, four taxiway bridges were built over the interstate. The taxi route assigned to flight 1141 would take them over the interstate, via the alpha-bridge, and then onto the parallel taxiway where they would have a straight shot to the opposite end of the runway for takeoff. Reaching the alpha-bridge, however, the crew found that the bridge which usually handles opposite direction traffic, the bravo-bridge, was closed. There was a fifteen to thirty minute wait to cross the alpha-bridge.

During the wait, a Flight Attendant entered the cockpit and started a casual conversation with the pilots. The Federal Aviation Administration requires a "sterile cockpit" between the time of pushback from the gate and the time that the aircraft passes through 10,000 feet. That is, the crew shall not engage in any conversation not directly related to the operation of the aircraft within that time period. The crew's conversation with the Flight Attendant, which involved such topics as the "gooney birds at Chicago Midway," different sorts of mixed drinks, and "the dating habits of our flight attendants," were clearly in violation of this policy.

After approximately a twenty-five minute wait, 1141 was cleared to cross the alpha-bridge, join the taxiway which runs parallel to 18L/36R, and taxi to the far end of the runway where it would depart. Nearing the end of the taxiway at 8:52am, the aircraft was placed into sequence behind a Delta Air Lines 737-232, a Continental DC-9-32, an American MD-82, and an American DC-10. At 8:57am, the preceeding American DC-10 was cleared for takeoff, and 1141 was cleared to "taxi into position and hold 18L, expect one minute for wake turbulence behind the heavy DC-10." The crew requested a two minute delay from Air Traffic Control, which was granted, and after a 30-second delay for traffic crossing the runway downfield, was cleared for takeoff at 8:59:32.

During the takeoff roll, everything appeared totally normal. The first officer made the call of "power's set, engine instruments look good, airspeed's comin' up both sides" just as the aircraft passed through 80 knots. When the Captain attempted to rotate the aircraft, however, things went terribly wrong.

Two loud "pops" were heard on the cockpit voice recorder and the stickshaker immediately activated to warn the crew that plane was nearing a full stall. The Captain stated “something’s wrong” as the plane began to roll violently and one or more of its engines went into compressor stall and began to surge as the airflow over the wings was disrupted by the critical angle of attack. The next words spoken in cockpit as the 727 slowly became airborne were the Captain saying "Engine Failure!” and the First Officer concurring “We got an engine failure!" Ten seconds before the first impact, the Captain exclaimed “we’re not gonna make it” in a panicked tone. The First Officer reacted by trying to call the tower but he only managed to blurt out “eleven forty one’s…!” Just prior to impact the Captain commanded “full power up!,” but it was too late.

At a height of 22 feet above the ground, one thousand feet from the end of the runway, and an airspeed of 165 knots, the Boeing 727's right wing impacted an ILS localizer antenna, spinning the aircraft longitudinally and causing enough of a disruption of airflow over the wings that the aircraft crashed to the ground.

After impact, the aircraft broke into two peices and skidded to a stop some four thousand feet from the end of the runway. As evacuation procedures were begun, a fire broke out near the fuel lines to the engines in the rear of the aircraft. Out of the 108 passengers and crew aboard, 14 did not live to tell their story. The Captain was the last person to leave the aircraft alive, removed some 45 minutes after the accident.

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Investigators could not determine why an airplane with no mechanical anomalies, and an experienced Captain at the controls, would simply fail to develop lift. The only logical explanation for the accident was that the wing flaps and leading edge slats had not been extended for takeoff. The crew had, before takeoff, checked the item as “fifteen, fifteen, green light.” Then a breakthrough; the takeoff warning horn was retrieved from the wreckage, and found to be inoperable. The possibility began to surface that, although the First Officer replied “fifteen, fifteen, green light” to the “Flaps” item on the “Before Takeoff Checklist,” he failed to actually check the position of the flap lever and flap position gauges.

During further study of CVR and wreckage it became apparent that the crew never configured the flaps for takeoff. The first officers “fifteen, fifteen, green light” reply was most likely only a reflex response to the checklist challenge. The inoperational takeoff warning horn did not alert the crew of any anomaly during the takeoff roll; had it been operational this disaster most likely would have been avoided. In addition, had the Captain moved the throttles to their forward stops immediately after stickshaker activation and lowered the nose, the aircraft most likely would have recovered from the stall.

The National Transportation Safety Board, in its official report, adopted this scenario as the official cause of the accident. Cited for blame in the report was "the Captain and First Officer's inadequate cockpit discipline which resulted in the flightcrew's attempting to takeoff without the wing flaps and slats properly configured," and listed as a contributing factor was the failure of the takeoff warning horn system.



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