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Air-Safety Computer System Has Trouble Taking Off

By Sam WalkerStaff writer of The Christian Science Monitor / January 6, 1995


NASA built it, pilots praise it, and air-safety experts say it can save lives. But you won't find the takeoff performance monitor (TOPM) aboard any commercial aircraft.

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In fact, this 10-year-old safety system has not been approved by the Federal Aviation Administration (FAA) and is not yet available as an option on new jets.

Airlines, manufacturers, and FAA officials say the cost and liability burdens of TOPM outweigh its benefits, and that industry losses of more than $10 billion in the last five years preclude installing every new gadget.

But critics, rattled by recent crashes, say the fate of TOPM shows that the industry and the FAA are more interested in profitability than in public safety.

``If it doesn't carry passengers or make money, the airlines don't want it,'' says Don Cornwall, technical chairman of the 110,000-member Airline Pilots Association. ``Whenever something comes up that costs money, the airlines really scream.''

As industry leaders and regulators gather Monday for an air-safety summit in Washington, safety advocates say growing public pressure may provide the push TOPM and other promising safety technologies need.

Developed in 1985 at NASA's Langley Research Center in Hampton, Va., the TOPM computer is designed to help pilots handle takeoff mishaps more quickly and safely (see chart).

As an aircraft barrels down the runway, TOPM collects data and flashes a display on the cockpit windshield indicating where on the runway the aircraft will lift off. If TOPM senses an acceleration problem, it calculates whether the pilot has enough runway left to stop. If so, a ``stop'' signal alerts the crew to slam on the brakes. If not, TOPM advises the pilot to complete the takeoff.

Currently, pilots use a mathematical formula to calculate their probable point of liftoff before leaving the gate. The problem with this system, TOPM advocates say, is that if one engine fails or a tire blows out during takeoff, that calculation is rendered useless. Moving at speeds of up to 153 m.p.h., pilots then have only a few seconds to determine whether to abort the takeoff and risk skidding off the end of the runway or to pursue liftoff.

While such troublesome takeoffs occur less than 1 percent of the time, studies show that they account for 10 percent of all serious airplane accidents. According to the National Transportation Safety Board (NTSB), 4,000 takeoff-related accidents occurred between 1983 and 1990, resulting in 1,378 deaths.

After a McDonnell-Douglas DC-10 skidded off the end of a runway at Dallas-Fort Worth International Airport in 1990, injuring eight passengers, an NTSB report concluded that ``runway overruns following high speed rejected takeoffs have resulted and continue to result in accidents.'' Two years later, a Boeing study determined that takeoff is the only segment of flight safety that has not seen any recent improvement.

But despite vigorous support from NASA, NTSB, and the Airline Pilots Association, the FAA has not concluded any substantial review of TOPM technology, and no manufacturer has implemented it.

The main reason is economic, says Ratan Khatwa, an engineer at the Dutch National Aerospace Lab in Amsterdam who spent eight years developing a TOPM system for European carriers. ``If there is no commercial advantage, carriers are reluctant to buy new technology,'' he says. ``These days you have to sell safety.''

Leo Jansen of the Aviation Safety Institute in Worthington, Ohio, says the only safety technologies the industry willingly embraces are those that also save money. The economic benefit of TOPM appears small, Jansen says, ``especially when you tell people that you'll only use it less than 1 percent of the time.''