1988 — Aug 31, Delta Air Lines #1141 takeoff crash & fire, Dallas/Fort Worth AP, TX– 14

— 14  Henry. FIR: Delta Flight 1141 Crash, Dallas/Fort Worth Airport, August 31, 1988. P. 1.

— 14  NTSB. 08/31/88 Delta: Official Accident Report Index Page. 9-26-1989.

 

Narrative Information

 

Henry/NFPA: “At approximately 9:00 a.m. on Wednesday, August 31, 1988, a Boeing 727 in service for Delta Air Lines crashed during takeoff at the Dallas/Fort Worth Airport. The plane experienced a low impact crash off the end of the runway and traveled 3300 feet along the ground beyond the end of the runway. It left a trail of burning fuel and grass, and the fuselage opened in some locations. Of the 108 persons onboard, 94 survived…. [Abstract, p. 1.]

 

NTSB: “This report examines the crash of Delta flight 1141 while taking off at the Dallas-Forth Worth, Texas on August 31, 1988. The safety issues discussed in the report include flightcrew procedures; wake vortices; engine performance; airplane flaps and slats; takeoff warning system; cockpit discipline; aircraft rescue and firefighting; emergency evacuation; and survival factors. Recommendations addressing these issues were made to the Federal Aviation Administration, the American Association of Airport Executives, the Airport Operations Council International, and the National Fire Protection Association….   [Abstract, p. 2 of 129.]

 

“Probable cause: (1) The Captain and First Officer’s inadequate cockpit discipline which resulted in the flightcrew’s attempt to take off without the wing flaps and slats properly configured; and (2) the failure of the takeoff configuration warning system to alert the crew that the airplane was not properly configured for the takeoff.

 

“Contributing causes: “Delta’s slow implementation of necessary modifications to its operating procedures, manual, checklists, training, and crew checking programs which was necessitated by

significant changes in the airline following rapid growth and merger; the lack of sufficiently aggressive action by the FAA to have known deficiencies corrected by Delta and the lack of sufficient accountability within the FAA’s air carrier inspection process.” (p. 4 of 129.)

 

“Description: “After a normal takeoff roll, the captain heard two explosions as the main gear wheels left the ground. The airplane began to “roll violently,” struck the instrument landing system localizer antenna array and came to rest about 3,200 feet beyond the runway. The airplane was destroyed by impact forces and postcrash fire. Fourteen were killed, 94 survived.” (p. 4 of 129.)

 

“Executive Summary: “About 0901 central daylight time on August 31, 1988, Delta Air Lines, Inc., flight 1141, crashed shortly after lifting off from runway 18L at the Dallas-Fort Worth International Airport, Texas. The airplane, a Boeing 727-232, U.S. Registry N473DA, was a regularly scheduled passenger flight and was en route to Salt Lake City, Utah, with 101 passengers and 7 crewmembers.

 

“The flightcrew reported that the takeoff roll appeared to be normal in all respects, with no warning lights, audible warnings, or unusual engine instrument conditions. The captain stated that the rotation was initially normal, but as the main gear wheels left the ground he heard “two explosions.” He said it felt as though the airplane was experiencing “reverse thrust.” The captain stated that the airplane began to “roll violently.”

 

“The airplane struck the instrument landing system (ILS) localizer antenna array approximately 1,000 feet beyond the end of runway 18L, and came to rest about 3,200 feet beyond the departure end of the runway. The flight was airborne approximately 22 seconds from liftoff to the first ground impact near the ILS localizer antenna. The airplane was destroyed by impact forces and the postcrash fire.

 

“Of the persons on board flight 1141 12 passengers and 2 crewmembers were killed, 21 passengers and 5 crewmembers were seriously injured, and 68 passengers sustained minor or no injuries….” (p. 5 of 129)

 

“History of the Flight: On August 31, 1988, Delta Air Lines, Inc., flight 1141, a Boeing 727-232, N473DA, was a regularly scheduled passenger flight from Jackson, Mississippi to Salt Lake City, Utah, with an intermediate stop at the Dallas-Fort Worth International Airport (DFW), Texas. The flight was conducted subject to the provisions of Title 14 Code of Federal Regulations (CFR), Part 121….” (p. 7 of 129).

 

Injuries to Persons: Cabin crew (2); Passengers (12);[1] Total (14). [p. 9 of 129.]

 

“Medical and Pathological Information. The cause of death of the 11 passengers and the two flight attendants was determined to be smoke inhalation. Levels of carboxyhemoglobin (COH6) ranged from 15 to 81 percent. Tests for drugs and ethanol were negative in all 13 persons. A 14th fatality was a passenger who had successfully evacuated but later attempted to reenter the burning airplane. This passenger died of severe burns, 11 days after the accident….” (p. 37 of 129.)

 

“Fire. A fire ensued after the right wing contacted the ground and quickly spread to engulf the rear, right side of the airplane after it came to rest. The fire subsequently penetrated the fuselage.” (p. 38 of 129.)

 

“Survival Aspects…. The investigation found that although the fuselage had separated in several places, the occupiable volume of the cabin was not substantially compromised. Passengers generally stated that impact forces were not severe. Further, the cause of deaths of the passengers in the aft section of the cabin were attributed to smoke inhalation and fire rather than impact injuries. Exit from the aft cabin was hampered by the fire that impinged on the right side of the airplane. Exit from the mid and forward cabin was through breaks in the fuselage and through the left side exits, except for the left aft service door which was not opened.” (p. 39 of 129.)

 

“Analysis…. The investigation determined that the flightcrew was qualified in accordance with applicable Federal Aviation regulations and company regulations.

 

“The airplane had been maintained and operated in accordance with applicable Federal Aviation regulations and company operations specifications. There was no evidence of any preexisting discrepancies or of any preimpact structural, flight control, or engine failures which would have been causal to the accident.

 

“Although the No. 1 fuel gauge was inoperative and the fuel tanks were not drip-sticked following refueling, the evidence indicates that the airplane was refueled properly. There was no evidence that there was a fuel imbalance that would have caused flight control problems.

 

“There were no abnormal airplane movements prior to takeoff, changes in ground control frequencies, or weather-related factors which could have distracted the flightcrew from its duties.

 

“The analysis of this accident addressed the performance of the airplane’s trailing edge flap and leading edge flap and slat control systems, as well as the performance of the airplane’s takeoff warning system and the performance of the engines. Also addressed in this analysis was the FAA’s surveillance of Delta and Delta’s efforts to correct or improve problem areas identified during FAA inspections.” (p. 67 of 129.)

 

“Flightcrew Actions After Takeoff. Even though the analysis determined that the flightcrew did not configure the airplane properly for takeoff, the accident may not have been inevitable. Thus, the flightcrew’s actions after takeoff were analyzed to determine whether the accident could have been prevented or otherwise minimized….

 

“During the public hearing, the second officer testified that, after the aircraft rolled to the right, he observed that both of the captain’s hands were on the control yoke. Therefore, it is concluded that the captain’s call of “full power” was a command for the first officer to advance the throttles, and that power had not been increased prior to 0900:34.7. Despite the captain’s statement at the public hearing that he applied maximum power before impact, there is no evidence that power was ever actually increased above the reduced takeoff rating.

 

“The captain testified that Delta’s procedures when encountering stickshaker after liftoff were to apply maximum available thrust, rotate toward 15° of pitch, and to respect all stall warnings, i.e., stickshaker or buffeting. Additionally, the captain testified that he followed Delta’s procedures after encountering stickshaker. The performance study found that the airplane was rotated over 13° when it passed the ILS antenna and may have exceeded 15° at various portions of the flight. In any event, the nose of the airplane was not lowered to silence the stickshaker.

 

“The investigation found that Delta’s procedures for encountering a stickshaker or buffeting close to the ground are, in part, to apply maximum power and to rotate toward 15° of noseup pitch attitude. Additionally, the Delta procedure states that the pilot is to stop rotation if stickshaker or buffeting is encountered. It is concluded that not applying maximum thrust after the onset of stickshaker and not respecting stickshaker warnings were the significant reasons for the captain’s inability to gain control of the airplane after liftoff.

 

“The investigation found that the most appropriate reaction after activation of the stickshaker was to apply maximum available thrust and to lower the nose below stickshaker AOA. Although a clean wing is not an authorized takeoff configuration for the B-727, the airplane performance analysis showed that a marginal climb capability was available if stickshaker AOA had not been exceeded and/or if maximum power had been applied within 3 seconds of initial stickshaker activation. Maximum throttle position increases thrust approximately 25 percent from about 34,500 to 43,000 pounds total thrust. Therefore, had maximum power been applied 3 seconds after stickshaker, performance calculations predict that the airplane would have gained 20 knots of airspeed and over 200 feet of altitude before reaching the ILS antenna. If stickshaker AOA had not been exceeded, further altitude gain could have been expected. Moreover, a check of configuration–the flap control lever and flap indications–immediately upon activation of the stickshaker would have disclosed the reason for the airplane’s performance deficiency. Had the first officer or second officer moved the flap control immediately, the extension of the leading edge devices would have provided sufficient stall margin to regain control.” (p. 78 of 129.)

 

“FAA Surveillance. The investigation of this accident found that the FAA had conducted four inspections of Delta since 1985. With the exception of the 1986 NASIP inspection, there were consistent observations of deficiencies in Delta’s training, checking, and line operations that were evident from 1985 to as recently as October 1988. These deficiencies included poor flightcrew discipline and coordination, including improper use of checklists, and abuses in Delta’s training and checking programs.

 

“The Safety Board gathered considerable testimony at the public hearing concerning the oversight of Delta by the FAA. The relationship between an air carrier and the FAA is unique and complex. Deregulation of the industry in 1978, combined with the growth in air travel, has made the FAA’s job of overseeing the airlines more difficult than it use to be. Nevertheless, the FAA was aware of certain deficiencies in Delta’s check airman program as far back as 1985. Additionally, in 1987, the incidents involving Delta flightcrews and the findings of the 1987 inspection team should have indicated to Delta and the FAA that immediate corrective action was necessary.

 

“The results of the 1987 and 1988 special inspections of Delta indicated that a potential for a mishap existed if remedial action was not taken. Many of the observations made by the inspection teams were evident in the cockpit of flight 1141–that is, poor discipline, poor crew coordination, and a lack of knowledge concerning individual responsibility. While the air carrier has the primary responsibility to operate in a safe manner, the deficiencies noted by the FAA special inspection teams warranted corrective action by Delta and aggressive followup by the FAA. The FAA personnel questioned on this point at the public hearing responded by stating that the deficiencies noted by the special inspection teams at Delta were “non-regulatory” in nature, and therefore beyond the principal inspector’s direct control. While this may be true from a technical viewpoint, the purpose of the special inspection teams sent to Delta was to look beyond

minimum compliance and to identify operational areas that needed improvement….” (p. 83 of 129.)

 

“Fire Propagation. Examination of the physical evidence indicated that the external fire was initiated when the right wing and tail struck the localizer antenna array. The fire intensified when the airplane struck the lip of the depression in the terrain. The right wing was destroyed and the fuel tanks lost all structural integrity. Flames not only impinged on the right side of the fuselage, but extended around the fuselage, heating the inboard wing area on the left side. As the fuselage slid, the aft cargo door opened and was pushed in. The forward door of the aft cargo compartment opened outward, and was torn off at its hinges. The hinges ripped the fuselage open causing a large opening in that area.

 

“Evidence showed that the fire entered the aft cargo compartment before the airplane came to rest. After the airplane stopped, the fire burned through the cargo compartment liners and cabin floor. The fire also entered the cabin through the aft break in the fuselage, the opened right-hand overwing exit, and later through a burn through in the center wing box area. The fire entering the fuselage through the aft break trapped passengers in the aft end of the cabin. The fire burning through the floor probably caused the fatalities in that area. The autopsy reports showed the cause of death to all fatalities as smoke inhalation.

 

“The forward cabin remained survivable for about 4 minutes and 20 seconds, despite the large fuel fire at the ruptured area. Some of this survival time can be attributed to the use of fire blocking materials on the seat cushions….” (p. 90 of 129.)

 

“Conclusions….

 

“3. The flightcrew deviated from Delta’s policies and procedures with respect to checklist execution, cockpit discipline, and required callouts.

 

“4. Extensive non-duty related conversations and the lengthy presence of the flight attendant in the cockpit reduced the flightcrew’s vigilance in ensuring that the aircraft was properly prepared for flight….

 

“8. The flightcrew did not extend the airplane’s flaps or slats for takeoff.

 

“9. The takeoff warning system had an intermittent failure problem which was not corrected during the last maintenance activity and which manifested itself during the takeoff of flight 1141.

 

“10. Failure of the takeoff warning system to activate was most likely due to contamination or misalignment of the takeoff warning system throttle switch.

 

“11. Failure of the auto pack trip light to illuminate as the throttles were advanced should have

been reported as a malfunction to the captain by the second officer.

 

“12. The captain’s action of continuing to increase AOA after the onset of stickshaker and his

failure to apply maximum power in accordance with Delta’s procedures reduced the climb and

acceleration performance of the airplane.

 

“13. Delta Air Lines’ corporate philosophy of permitting maximum captain discretion contributed to the poor discipline and performance of flight 1141’s flightcrew.

 

“14. The FAA was aware of the flightcrew performance deficiencies in Delta’s operations, as well as irregularities in Delta’s training and checking programs.

 

“15. Neither Delta nor the FAA took sufficient corrective actions to eliminate known flightcrew

performance deficiencies….

 

“20. A number of lives were saved by the use of the fire blocking layer on the passenger seats. An exact number of additional survivors could not be determined….” (p. 98 of 129.)

 

Sources

 

Henry, Martin F. Fire Investigation Report: Delta Flight 1141 Crash, Dallas/Fort Worth Airport, August 31, 1988. Quincy, MA: National Fire Protection Association, no date.

 

National Transportation Safety Board. 08/31/88 Delta: Official Accident Report Index Page (NTSB/AAR-89/04) – Delta Air Lines, Inc. Boeing 727-232, N473DA, Dallas-Fort Worth International Airport, Texas, August 31, 1988. Washington, DC: NTSB, 9-26-1989, 129 pages. Accessed 7-14-2016 at: http://www.faa.gov/about/initiatives/maintenance_hf/library/documents/media/human_factors_maintenance/delta_air_lines.inc._boeing_727-232.n473da.dallas-fort_worth_international_airport.texas_august_31.1988.pdf

 

 

 

[1] Notes in footnote: “One passenger successfully exited the aircraft, but was severely burned when he attempted to reenter the cabin. Hew died 11 days later. It is believed that he attempted to reenter the cabin in an effort to provide assistance to his wife and other passengers in escaping from the aircraft.”