Would Add 15 Percent Safety Margin To Calculations

Less than two weeks before an NTSB hearing into last December's runway overrun accident at Chicago's Midway airport, the FAA has proposed tougher standards for how airline pilots compute available landing distances.

Current regulations -- which require commercial airline pilots to calculate before takeoff the needed runway length at their destination -- weighs such factors as touchdown speed, landing weight and wind conditions. Considerable safety margins are built into those calculations, to take into account changing weather conditions and other factors.

What the current regs don't require, however, is for pilots to recalculate those figures en route in the face of deteriorating conditions at the destination airport.

Under the proposed guidelines, the FAA would require all pilots to recompute landing distances enroute should weather take a turn for the worse -- and to build in an extra 15 percent margin of safety into those landing distance figures, just to be on the safe(r) side.

USA Today reports several airlines have their own procedures in place now for such occurrences -- but there is no standardized process.

Had the new regulations been in place last December, it is likely the Southwest Airlines jet that overran the runway at Midway in a snowstorm -- and struck two cars on a nearby road, killing a young occupant in one -- would have been diverted to another airport instead, as new landing distance calculations would have shown the jet was at the edge of, or outside, the margin of safety for Midway's short runways.

The FAA's proposal is a slightly different take on handling runway overruns than what the NTSB has proposed. Two weeks after the Midway accident, the safety board urged the FAA to reexamine some airlines' use of thrust reversers when calculating landing distances. The pilots on the Southwest Airlines jet had difficulty activating the reversers.

"We think that this approach will give us an even broader safety benefit than the NTSB's recommendation," FAA spokeswoman Laura Brown said.

No word yet on what the NTSB thinks of the FAA's proposal, which could go into effect on September 1... nor how the airlines feel about adopting a regulation that would likely lead to more diverted flights.

FMI: www.faa.gov