WASHINGTON — Under-inflated tires — a problem that may be widespread on business jets — caused a Learjet crash 18 months ago that killed four people and seriously injured Blink 182 drummer Travis Barker and the celebrity disc jockey DJ AM, federal safety investigators said Tuesday.
The National Transportation Safety Board also said that a design flaw in the Learjet 60 and a decision by the flight's captain to abort takeoff in Columbia, S.C., were also at fault in the accident.
Investigators told the board they found that operators of air charters often aren't aware how rapidly the tires of some business jets can lose pressure and aren't checking tire pressure frequently enough.
"This accident didn't have to happen," said NTSB Chairman Deborah Hersman. The crash, she said, should be a warning to everyone in the aviation industry that "there are no small maintenance items because every time a plane takes off, lives are on the line."
The board also said the Federal Aviation Administration and Learjet Inc., a subsidiary of Bombardier Aerospace, didn't take aggressive enough action to correct a design flaw involving the Learjet 60's thrust reversers despite knowing that the flaw played a role in a similar 2001 accident in Alabama in which two people were seriously injured.
Barker and DJ AM, also known as Adam Goldstein, had just wrapped up a concert in Columbia and were taking off from a local airport in their chartered jet with two of Barker's staff members and two pilots on Sept. 19, 2008.
As the plane hurtled down the runway at about 150 mph, all four tires exploded only seconds apart. Pieces of the tires, hurled at high speeds, damaged the plane's hydraulic system, causing the brakes to fail.
The flight's captain, who had only 35 hours of experience flying a Learjet 60, made a split-second decision to abort the takeoff even though the plane had already exceeded the speed at which the takeoff could be safely rejected, investigators said. Pilots are trained not to halt a takeoff after reaching a certain speed as long as the plane is capable of flight.
Adding to the problem, and eliminating all ability of the pilots to stop the plane, was damage to an electronic sensor that caused the plane's computers to conclude the plane was airborne when it was still on the ground. This automatically closed the thrust reversers — which can be used to slow a plane — and increased the power propelling the plane forward.
The jet hurtled off the runway, crashed through a fence, crossed a five-lane highway, hit an embankment and was engulfed in flames.
Barker and Goldstein were the only survivors. Goldstein died of a drug overdose a year after the accident.
The charter company that operated the plane, Global Exec Aviation, estimated the last time the pressure in the plane's tires had been checked was three weeks before the accident, investigators said. However, the type of tires on the plane lose about 2 percent of their pressure a day and, if not maintained, would need to be replaced after eight days, investigators said.
A pilot would be unable to tell that the tires were under-inflated simply by looking at them, investigators said. FAA regulations also prohibit commercial pilots from using instruments to measure tire pressure, they said.
The board said there was no problem with the design or manufacture of the tires. However, they faulted Global Exec Aviation for not maintaining proper pressure, and issued a series of recommendations to the FAA regarding tire pressure, including requiring that all commercial passenger planes have tire-pressure monitoring systems.
The board also recommended that the FAA require Learjet to fix the flaw that caused the problem with the thrust reversers. The plane involved in the accident was manufactured in 1993. However, the FAA didn't require that model — whose original design was approved in 1966 — to be updated to meet more modern safety requirements that aircraft designs be evaluated for what kind of impact the failure of one system might have on the aircraft's other systems.
Barker and family members of his bodyguard, Charles Monroe Still Jr., and his assistant, Chris Baker, who were killed in the accident, have reached legal settlements with several companies, including Global Exec Aviation, ITAS Inc., which owned the plane, Learjet Inc. and Goodyear Tire & Rubber Co.
Global Exec Aviation and ITAS have filed their own lawsuit against the plane's manufacturers.