The Federal Aviation Administration, reacting to reports that two people died when a jammed emergency exit blocked their escape from a burning airliner at Detroit last month, said yesterday it will order an immediate inspection of tail cone exits on all DC-9 and MD-80 aircraft.
The announcement came within hours after the National Transportation Safety Board reported that the tail cone release handle on Northwest Airlines Flight 1482 was broken and a piece of it had jammed the cable that is designed to pop open four locks holding the cone to the airplane fuselage. The mechanism, when activated, allows the cone to fall free and an escape slide to inflate.
A flight attendant was found lying just below the jammed handle and a passenger was found dead nearby.
Eight passengers died Dec. 3 when Flight 1482, apparently lost in fog, turned onto a runway just as a Northwest Boeing 727 was taking off. The wing tip of the 727 raked the side of the DC-9, which was then destroyed in a fire as 36 passengers and crew scrambled to safety.
The board said that a post-crash test of the release mechanism, which is designed to pop open with 35 pounds of pressure, would not budge with up to 90 pounds of pressure. It said its investigation had found "serious deficiencies" in the design of the mechanism, which it said is prone to fracture under relatively low stress.
The board, which investigates accidents but has no regulatory power, issued an urgent recommendation that DC-9 tail cone assemblies and escape handles be inspected. The board also recommended that McDonnell Douglas redesign the tail cone release mechanism on the DC-9 and the MD-80.
"We agree with the objectives of the board," said FAA spokesman Bob Buckhorn. He said the FAA will issue an order this week.
Anthony J. Broderick, the FAA's associate administrator for regulation and certification, said the agency is already working with McDonnell Douglas and the airlines to redesign the mechanism. He said he hopes to complete the process within weeks and issue an order making the new design mandatory.
The DC-9 is a mid-range jet with two tail-mounted engines, built by McDonnell Douglas between 1965 and 1982. McDonnell Douglas spokesman John Thom said 916 remain in operation worldwide, 60 percent of them in the United States. The MD-80, an updated version of the DC-9, entered production in 1980 and 825 have already come off the production line with hundreds of others on order.
McDonnell Douglas yesterday issued a statement saying it had issued a service bulletin before Christmas calling on aircraft operators to inspect the release handle. The statement said the company is working with the FAA and the board in the investigation.
However, the company said that "in 25 years of service by the DC-9, we have had no other instances reported of a broken handle."
The company recommends that the tail-cone mechanism be activated, just as it would in a crash, every time a plane undergoes a "C" maintenance check, which comes about every three years. The DC-9 involved in the accident had had such a check last Nov. 6, and the board said the tail cone was jettisoned and reinstalled without difficulty.
However, the board said it had determined that neither the mechanics nor the quality control inspector involved had received training in the installation process, and that Northwest's maintenance procedures do not follow the detailed inspection guidelines in the DC-9 maintenance manual.
The board said that may account for another problem found during the probe -- misrigging of one of the four locks. The misrigging would not have accounted for the door's jamming, however, the board said.