Four people, including the pilot and co-pilot, were killed when a Learjet 60 ran off the end of the runway just before midnight Sept. 19. Investigators examining the fiery wreckage found that the thrust reversers devices on the back of jet engines that divert their thrust forward, helping to slow a plane or force it backward were not in the right position to help slow down the plane.
The pilots were trying to abort takeoff at the Columbia Metropolitan Airport when the accident happened.
Changing the design of the thrust reversing system on the Learjet 60 to make its operation more intuitive could potentially help avert such deadly crashes, the National Transportation Safety Board wrote as one of its six recommendations.
"The only way to reduce forward thrust under these abnormal circumstances is to move the reverse levers to the stowed position," something the NTSB said would "be counterintuitive to a pilot who was trying to abort a takeoff by applying maximum reverse thrust. Initially, flight crew members trying to slow the airplane would likely think that they are receiving the reverse thrust that they commanded until they realize that the airplane is not slowing."
An aviation expert who examined the recommendations said a switch damaged when one of the plane's tires blew out caused the reversers to shut down as if the plane were already in flight and did not need the thrusters at that point.
"The airplane thought it was in the air rather than on the ground," said Mary Schiavo, former inspector general for the federal Transportation Department. The pilots would have had just seconds to realize the problem and correct it, she said.
The recommendations now go to the Federal Aviation Administration for consideration. NTSB also recommended that older planes be retrofitted to meet the new specifications, and that Learjet develop a better way to alert pilots, either through sounds or flashing lights, so they know quickly if a thrust reverser is improperly stowed.
All Learjet 60 pilots should receive more training on the thrust reversers, and the FAA should also evaluate engines for the Raytheon Hawker 1000 business jets, since they share similarities with the Learjet 60 engines, the NTSB recommended.
A spokesman for Learjet manufacturer Bombardier Aerospace did not immediately return a message seeking comment.
Barker and DJ AM, whose real name is Adam Goldstein, had performed together under the name TRVSDJ-AM at a free concert in Columbia the night of the crash. The jet, which was headed for Van Nuys, Calif., is owned by Global Exec Aviation, a California-based charter company, and was certified to operate at the time.
The NTSB has not issued its final report on the crash. In preliminary findings issued last year, investigators said the plane was traveling 156 mph just before its pilots tried to abort the takeoff. Officials said there was little rubber left on the jet's wheels, and the brakes were badly damaged.
Some aviation experts have said the pilots should have known they wouldn't be able to safely stop the plane and should have aborted the takeoff earlier.
In eerie recordings subsequently released by investigators, co-pilot James Bland warned air traffic controllers his plane was "going off the end" of a runway before it crashed, killing him and three others.
"Roll the equipment, we're going off the end," Bland told controllers, who then scrambled to divert other planes and summon emergency personnel after the jet shot off the runway, ripped through a fence and came to rest in flames.
Aviation authorities have said other recordings showed the jet's crew thought a tire had blown before takeoff. The NTSB has said pieces of tire were recovered about 2,800 feet from where the plane started its takeoff down the 8,600-foot runway.
The owner and operator of the jet that crashed sued the Columbia airport, alleging that the design of the area beyond the runway contributed to the seriousness of the crash: There was not enough room for the plane to stop, a fence and other equipment damaged the jet's fuel tanks and the lowered roadway around the airport caused the plane to crash nose first into a raised embankment.
The companies are seeking more than $12 million in damages, and the airport has denied the allegations.
At least four other lawsuits have been filed after the crash, including ones by Barker and Goldstein in Los Angeles. Barker's lawsuit, filed in November, alleges that the plane was "defective" and claims the pilots were improperly trained and should have tried to take off rather than continue down the runway.
On Friday, Suellen Lemmon, the mother of co-pilot Sarah H. Lemmon, who died in the crash, filed a wrongful death lawsuit in Los Angeles Superior Court against Bombardier, Learjet and others.