Aviation Accident Summaries

Aviation Accident Summary LAX97FA276

HONOLULU, HI, USA

Aircraft #1

N740DA

Lockheed L-1011-385-1-15

Analysis

After maintenance completed troubleshooting and the aircraft taxied out for the final time, the aircraft had taxied 11.3 miles within a 3-hour period. There was no temperature gauge or tabular data available that could have informed the crew that heat buildup resulting from taxi distance was now at a level that potentially threatened the integrity of the tires. During the takeoff roll, the 3F tire exploded, resulting in vibration, shudder, and yaw. The sudden instability, combined with a phantom C1 cargo door light, caused the Captain to abort. The abort was initiated about Vr (165 knots) with approximately 6,000 feet of runway remaining. As the aircraft came to a stop, the nose wheels were 164 feet short of the overrun area for runway 8R. A brake fire began while the aircraft was stopping and the captain directed an emergency evacuation. The 2R and 4R doors failed to open, and the 4L and 3L doors were not used due to their proximity to the fire and smoke. The 4R door was jammed by a broken piece of backboard, and the 2R door malfunctioned due to a partially broken counterbalance spring. The flight attendant who attempted to open the 2R door did not attempt to manually lift the door. All evacuations were made through the 1L, 1R, 2L, and 3R doors. Firefighters had difficulty communicating with the flight crew and in verifying the total number onboard because the airline's passenger count does not include lap children. A total of 56 passengers and 2 flight attendants were treated for minor injuries, while 1 passenger received a broken ankle. All injuries were attributed to the use of the slides. Passengers failed to follow flight attendants and attempted to evacuate with their carryons. The airline did not effectively supervise the passengers after the evacuation and several began walking toward an active runway. An inspection of the 3R tire showed bead separation had occurred. The estimated bead temperatures during the takeoff roll reached between 350 and 400 degrees Fahrenheit. The bead begins to degrade between 250 and 280 degrees Fahrenheit.

Factual Information

HISTORY OF FLIGHT On August 7, 1997, at 1935 hours Hawaiian standard time, Delta Airlines Flight 54, a Lockheed L-1011-385-1-15, N740DA, aborted takeoff on runway 8R at the Honolulu, Hawaii, International Airport. A wheel/brake fire ensued as the aircraft came to a stop, and 1 passenger sustained serious injuries during the subsequent emergency evacuation, while another 59 received minor injuries. The aircraft sustained minor damage and the remaining 245 occupants were not injured. The aircraft was operated by Delta Airlines, Inc., as a scheduled domestic passenger flight from Honolulu to Atlanta, Georgia, under 14 CFR Part 121. The flight blocked out from the gate about. Visual meteorological conditions prevailed at the time and an IFR flight plan was filed. According to the airline maintenance records, the APU and the A channel of the area overheat system were inoperative when the crewmembers arrived at the aircraft. The dispatcher's records showed that the aircraft departed the gate at 1627 and proceeded to the end of 8R. During the initial taxi out the left wing duct fail light illuminated. The captain completed the checklist and the light went out; however, later in the taxi the light came on again. In view of these facts, the captain elected to return to the gate, arriving back there at 1655. The passengers were deplaned, maintenance was given the aircraft, and troubleshooting began at 1722. Maintenance personnel started all three engines and taxied out to runway 8R for an engine run. The overheat controller was replaced, the aircraft was again returned to the gate and, at 1845, the passengers and crew reboarded. The flight attendants reported that, during the initial takeoff roll, dozens of soda cans spilled from the forward left storage cabinet into the number three cross-aisle when two retaining latches malfunctioned. The takeoff roll continued without further incident until reaching V1 (155 knots), when the captain noted the illumination of the door caution light on the pilot's caution and annunciator warning panel (PCAWP). He announced to the crew that he intended to continue the takeoff. Identification of the door causing the pilot's caution light to illuminate can only be made from the flight engineer's annunciator panel. The C1 cargo door was subsequently identified by the flight engineer. About a second or so later, the captain felt the aircraft began to vibrate, shudder, and then begin a yaw to the left. He also perceived that the aircraft was settling to the left and heard what he described as "popping sounds." At this point, he decided that it would be unsafe to attempt a liftoff. The abort was initiated about Vr (165 knots) with approximately 6,000 feet of runway remaining. He slowed the aircraft by using full braking and reverse thrust. He corrected the left yaw with asymmetric brake and rudder inputs. The first officer stated that he assisted the captain by also applying the brakes with about 2,000 feet of runway remaining. He also reported their aborted takeoff to the control tower while the abort was in progress. Next, the flight attendants reported that a trash cart separated from its attachment fitting as the aircraft continued to decelerate. The cart began rolling down the aisle until it was stopped by one of the flight attendants. The cart brakes, which serve as a secondary latch, were set but did not prevent the cart from rolling. As the aircraft came to a stop, the nose wheels were 164 feet short of the overrun area for runway 8R. At this point, the second officer reminded the captain that the brakes would likely be very hot and suggested that an evacuation of the aircraft should be considered. The first officer contacted the tower requesting that fire and rescue personnel and equipment be dispatched. The captain was about to direct an evacuation when someone in the back of the aircraft shouted, "fire." Upon hearing that, the captain immediately ordered an evacuation and the second officer said, "abandon the aircraft" to the OBL (on board leader). The captain completed the evacuation checklist and activated the evacuation horn. After the horn sounded, he visually confirmed that the flight attendants were opening the doors and deploying the evacuation slides. After securing the cockpit with reference to the checklist, the cockpit crew went into the cabin to assist the flight attendants with the evacuation. The two control tower specialists, working in the midfield tower, stated that they watched as the aircraft taxied into position and held on runway 8R. After the pilot was cleared for takeoff, the aircraft began its takeoff roll. As the aircraft approached the midfield point, both controllers reported hearing a loud boom. They also observed smoke and flames emanating from beneath the aircraft. When the aircraft was finally stopped at the end of the runway, flames remained visible. They observed emergency rescue vehicles rolling on taxiway RA by the time the aircraft halted. INJURIES TO PERSONS According to the airline, 56 passengers and 2 flight attendants were treated for minor abrasions or smoke inhalation at the airport. A single passenger received a broken ankle and was transported to Queens hospital. Most of these injuries were sprains and abrasions that were sustained due to the use of the slides. DAMAGE TO AIRCRAFT After the accident, a Federal Aviation Administration (FAA) inspector arrived at the aircraft to oversee the investigation and the removal of the aircraft from the runway prior to the arrival of the Safety Board investigator. An airline mechanic documented the aircraft as follows: The 2R door was opened halfway with girt bar engaged, the slide pulled out halfway, and the emergency handle pulled into the full detent position. There was no evidence that the 3L door had been opened. The 4R door had opened approximately 2 inches with the girt bar engaged. The emergency handle was found in the stowed position. (Doors are numbered from fore to aft and then as left or right.) In the cockpit, all ignition switches were off, the boost pumps were on, the throttles were at idle, and the fire T-handles were pulled. The flaps were at 14 degrees, the spoilers were down, there was minor damage to right inboard leading edge slat, and the 3R brake line was severed. The right engine was inspected for FOD; however, none was found. (Brakes and wheels are numbered from the left to right and then as front or rear.) An inspection of the C1 door revealed no physical damage or other anomalies associated with the door latching mechanism or proximity sensor. The 3R brake line was fractured and the leading edge slat had minor impact damage and black smears, both in the vicinity of the 3F tire. There were black smears on the fractured brake line. The 3F tire was fragmented. The 3F fuse plugs were intact. The 2L slide was found to have partially deflated. When maintenance personnel inspected it, they discovered it had a slow leak. The 4R slide backboard was cracked and a piece of the backboard was found lying in the forward doorsill. AIRCRAFT INFORMATION The dispatch records show that, as the aircraft reached the takeoff point on the runway, it was at its maximum gross weight for takeoff of 510,000 pounds and was carrying 183,000 pounds of fuel on board. All eight main gear tires use an independent anti-skid sensing and control that are independent of each other. The anti-skid system is designed to deactivate as the aircraft's speed drops below 13 to 17 knots. There is no cockpit monitoring system to warn of excessive heat buildup in the tires. In addition, there are no charts or warnings in the pilot's manuals to indicate how extended taxi distances can affect tire integrity. The aircraft was manufactured with brake temperature gauges as standard equipment; however, the airline declined the gauges and elected to use the panel space for other equipment. The procedure for closing the C1 cargo door calls for holding the door switch to the closed position until the green light appears. The green cargo door light means the electrical operation of the door is complete and further depression of the close door switch has no effect. The extinguishment of the individual cargo door light at the flight engineer's panel indicates the door is locked. A proximity sensor located at the door lock mechanism triggers this door locked logic. Additionally, a direct viewing window located on the exterior of the cargo door provides visual capability to ensure the door is properly closed and locked. COMMUNICATIONS After getting out of their vehicles and having to rely on their hand-held radios, the firefighters found that they were unable to communicate with the cockpit crew due to frequency incompatibility. Once the emergency checklist/shutdown was completed, the PA and inter-phone became inoperative since they are both powered by the DC essential buss, which was deactivated when the battery was switched to the off position. At this point, the flight attendants were unable to communicate electronically with the cockpit crew or vice versa. FLIGHT RECORDERS The flight data recorder was reviewed by Safety Board investigators at the Board's FDR laboratory in Washington, D.C. Takeoff parameters were normal until FDR Subframe Reference Number (FDR SRN) 15968. This corresponded to 159 knots IAS. Acceleration remained as expected until 15972 SRN, when the abort was initiated at 165 knots IAS. There were a number of data misses in this area. A reduction in the acceleration was noted just before 15972 SRN and the number 1 EPR showed a reduction at 15972 SRN. Aircraft deceleration began after 15973 SRN, after the aircraft had reached a peak of 168 knots IAS. Engines reached idle at about 15975 SRN and the reversers were deployed at 15976 SRN. Full reverse was in effect by 15980 SRN and at 135 knots IAS. At SRN 15997, the aircraft recorded its minimum reading of 46 knots IAS and remained there throughout the remainder of the abort. Full reverse was still in use at SRN 15998. The first positive reduction in reverse was at SRN 16001. Engines were at idle and the thrust reversers stowed by SRN 16004. By SRN 16005, deceleration on the aircraft reached minimum. The abort sequence lasted about 34 seconds. Braking was already in effect as was noted by the deceleration loads prior to the thrust reversers being deployed. The cockpit voice recorder was reviewed by Safety Board investigators at the Board's CVR laboratory in Washington, D.C. The final taxi out was unremarkable with no extraneous conversation. The crew started the No. 3 engine after being cleared to taxi into position and hold. The engine had 4 to 5 minutes of warm-up time before the takeoff roll started. When cleared for takeoff, the final checklist items were accomplished. The only discrepancy in any responses was the captain's reply to rudder pedal steering of "Coming On" instead of "On." As the aircraft reached V1, the captain said, "Door light, we're going" in response to the illuminated C1 cargo door light. About 5 seconds later a pop was heard, followed by a loud shuddering noise. The first officer called out the abort to tower. Someone said "110 knots" during the abort. About the time the aircraft stopped, a "dinging" chime began to sound and continued until a crewmember picked up the PA and inter-phone handset. The crew was discussing the possibility of hot brakes when the second officer mentioned the possibility of a fire. The captain ran the evacuation checklist and notified the flight attendants to evacuate. At this point, the CVR stopped recording. WRECKAGE AND IMPACT INFORMATION The first physical indication on the runway was a rubber smear. The smear could be traced from the its initial point to the final position of the 3F tire as it came to a stop on the runway. The 3F tire partially separated with 6,170 feet of runway remaining. Measurements indicated that the aircraft was on the center of the runway at the time. All deviation measurements were referenced from the right truck to the centerline. At 6,000 feet the right truck was 19 feet right of the centerline. Evidence of light braking began at 5,300 feet. At 5,000 feet, the right truck was 10 feet right of center. At 4,625 feet, the right truck reached its maximum left deviation of 7 feet right of the centerline. At 4,000 feet, the right truck was still 7 feet right of the centerline. Between 4,000 feet and 3,500 feet, it became difficult to see evidence of any left truck braking. At 3,575 feet, the right truck was 9 feet right of centerline and abeam the east end of taxiway RG. The right truck crossed the centerline at 2,750 feet. Between 3,500 feet and 2,200 feet, the left truck showed evidence of rubber removal from the runway surface. At 2,150 feet, the left truck started to deposit rubber on the runway. At 2,135 feet, the right truck was 7 feet left of the centerline. At 2,075 feet, the right truck started to deposit rubber on the runway. At 2,000 feet, the right truck was 4 feet left of the centerline. At 2,830 feet, the right truck crossed back over the centerline toward the right. At 1,510 feet and beyond the installed gear arresting cable, the right truck was 16 feet right of the centerline. At 1,750 feet to 900 feet, the left truck marks became more easily visible. At 1,000 feet and abeam the windsock, the right truck was 33 feet right of the centerline. At 900 feet, the right truck reached a maximum right deviation, 35 feet right of the centerline. With 417 feet remaining and abeam the eastern edge of taxiway RH, the right truck was 16 feet right of the centerline. Heavy skid marks began on the right truck with 405 feet remaining. No braking was evident during the last 200 feet on left truck. The aircraft stopped with the right truck 16 feet right of the centerline. The nose gear came to rest near the centerline and 164 feet from end of runway. The left main gear exhibited evidence of sooting and melting. The 1F and 2R hubs had fractured along the center seam and the tires were deflated. Rubber deposits and smearing on the runway corresponded to the position of the 3F tire. The tire marks continued from the initial rubber smear marks up to the point at which the 3F tire stopped on the runway. Heavy skid marks began with 405 feet remaining. FIRE An assistant fire chief at Fire Station No. 2 reported hearing the sound of what described as a normal takeoff until he heard two explosions, or pops, after which time he heard the sound of the engines throttling down. He then heard engines go into reverse and saw flames from the left gear as the airplane began decelerating. He made an announcement over the ground internet and stated that they were "rolling" before the initial alarm had been received from the tower. The response time from Station No. 2, which included three trucks, was between 45 seconds and 1 minute. By the time fire equipment and personnel arrived at the aircraft, the left main gear was fully involved, producing flames 10 to 15 feet high. They expelled foam from turrets for 10 to 15 seconds, successfully knocking down the fire. Next, they pulled out their hand lines and applied foam on the right main gear wheels that were glowing cherry red. After the fire was knocked down, a few small flare-ups occurred on the left truck, but they, too, were extinguished within about 8 minutes. After spraying the foam, a dry chemical extinguishing agent was applied. Fire Station No. 1 sent additional two trucks, for a total of five fire trucks responding to the scene. SURVIVAL ASPECTS The first and second officers stated that they were unable to get to their assigned evacuation positions at the over-wing exits due to the flow of passengers coming forward to exit through the front doors. The OBL asked the second officer to assist people as they came down the slide. He responded by exiting through the 1L door and then began assisting the passengers as they came down the slide. He stated that the total number of evacuees soon overwhelmed him. As they came down the slide,

Probable Cause and Findings

the cumulative distance taxied immediately prior to takeoff that precipitated an excessive heat buildup in the tires and resulted in the bead separation of a single tire during the takeoff roll. The absence of cockpit procedures/directives or monitoring equipment to identify this condition was a factor in the accident. Contributing to the accident was the unavailability of two emergency exits due to the malfunction of the 2R and 4R emergency doors

 

Source: NTSB Aviation Accident Database

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