WASHINGTON (June 10, 2010) — The Federal Aviation Administration (FAA) has issued a new airworthiness directive on Bombardier Learjet Model 60 aircraft that revises rules on tire maintenance and checking tire pressure for the airplanes.
The FAA alert, however, stops short of implementing the April 2010 recommendations of the National Transportation Safety Board (NTSB) that tire pressure on the Model 60 planes be checked daily, and that all transport-category airplanes be required to have tire pressure monitoring systems (TPMS).
“Because the allowable daily pressure loss for aircraft tires can result in tire pressures that are below acceptable operational values within only a few days, providing tire pressure information to a flight crew can help ensure proper inflation and safe operations,” the NTSB said. TPMS is already installed on some new airplanes and can be retrofitted on others, the board said.
In the alert, which appeared in the June 8 Federal Register and constitutes a final rule, the FAA said it believed that the current practice of pressure checks every 96 hours is sufficient. “The NTSB states that it would prefer that the tires be checked daily for proper pressure, but that 96 hours between pressure checks…allows for recognition of an underinflated tire before it reaches a point where the tire would need to be changed,” the agency said.
The FAA also rejected recommendations from Goodyear, the NTSB and others that the alert shouldn't be limited to Model 60 airplanes, which, according to the agency, have a tire failure rate more than twice as high as some other Learjet models.
The FAA issued its first advisory on airplane tire pressures a year ago, in response to an accident involving a Model 60 airplane at a Columbia, S.C., airport in September 2008. In that accident, the aircraft overran the runway during takeoff and crashed, killing four people onboard and injuring two others. All four main landing gear tires failed during takeoff, and NTSB investigators later found all four had been severely underinflated.