Federal investigators are urging that all commercial aircraft be equipped with Tire Pressure Monitoring Systems (TPMS) and that routine tire maintenance be made a higher priority among aviators.
According to the National Transportation Safety Board (NTSB), severely underinflated tires set the wheels in motion for a high-profile September 2008 crash in South Carolina that killed four people and seriously injured Blink 182 drummer Travis Barker and Adam Goldstein, a celebrity disc jockey known as DJ AM.
“This accident chain started with something as basic as inadequate tire inflation and ended in tragedy,” says NTSB Chairman Deborah A.P. Hersman. “This entirely avoidable crash should reinforce to everyone in the aviation community that there are no small maintenance items because every time a plane takes off, lives are on the line.”
All four tires had blown apart within seconds of each other, sending bits of rubber and other shrapnel into sensitive components of the plane, causing the brakes to fail.
Design flaws in the Learjet aircraft and pilot error in attempting to abort the takeoff following the tire failure were among other causes cited. The plane left the end of the runway at about 150 mph, struck airport lights, crashed through a fence and crossed a roadway before coming to rest on a berm.
“The investigation revealed that prior to the accident the aircraft was operated while the main landing gear tires were severely underinflated because of Global Exec Aviation’s inadequate maintenance,” says the NTSB. “The underinflation compromised the integrity of the tires, which led to the failure of all four of the airplane’s main landing gear tires during the takeoff roll.”
Shortly after the first tire failed, which occurred about 1.5 seconds after the airplane passed the maximum speed at which the takeoff attempt could be safely aborted, the first officer indicated that the takeoff should be continued but the captain decided to reject the takeoff and deployed the airplane’s thrust reversers, according to the probe. “Pilots are trained to avoid attempting to reject a takeoff at high-speed unless the pilot concludes that the airplane is unable to fly; the investigation found no evidence that the accident airplane was uncontrollable or unable to become airborne.”
The tire failure during the takeoff roll damaged a sensor, which caused the airplane’s thrust reversers to return to the stowed position. While the captain was trying to stop the plane by commanding reverse thrust, forward thrust was being provided at near-takeoff power because the thrust reversers were stowed. The Safety Board determined that the inadvertent forward thrust contributed to the severity of the accident.
The Safety Board also found that neither the Federal Aviation Administration (FAA) nor Learjet adequately reviewed the plane’s design after a similar uncommanded forward thrust accident that occurred during landing in Alabama in 2001. “While the modifications put into place after the Alabama accident provided additional protection against uncommanded forward thrust upon landing, no such protection was provided for a rejected takeoff,” officials contend.
The safety recommendations that the NTSB made to the Federal Aviation Administration as a result of the investigation are: Provide pilots and maintenance personnel with information on the hazards associated with tire underinflation, including the required intervals for tire pressure checks, and allow pilots to perform pressure checks in air taxi operations to ensure that tires remain safely inflated at all times; require tire pressure monitoring systems for all transport category airplanes; identify and correct deficiencies in both Learjet’s thrust reverser system safety analysis and the FAA’s design certification process to ensure that hazards encountered in all phases of flight are mitigated; require that simulator training for pilots who conduct turbojet operations include opportunities to practice responding to events other than engine failures near takeoff speeds; require that pilots who fly air taxi turbojet operations have a minimum level of pilot operating experience in an airplane type before acting as pilot-in- command in that type; and require that airplane tire testing criteria reflect the loads that may be imposed on tires both during normal operating conditions and after the loss of one tire.
For more information, visit www.ntsb.gov/Publictn/2010/AAR1002.htm.
