Jun. 10--By next winter airline pilots will be required to pad their estimates about the distance needed to land planes on snowy or wet runways, under a notice the Federal Aviation Administration has issued.
The proposed FAA rule change, prompted by the Southwest Airlines accident at Midway Airport in December, mandates adding at least a 15 percent margin to landing-distance calculations to ensure that planes can stop safely in bad weather.
"If the pilots don't have the extra 15 percent, they don't land there," said FAA spokeswoman Laura Brown.
A Southwest Boeing 737-700 that landed during a snowstorm at Midway on Dec. 8 skidded off the end of the slippery runway, plowed through fences and struck several vehicles on a street outside the airport. A 6-year-old boy riding with his family in a car was killed.
Investigators determined that the Southwest pilots--landing with a tailwind on the snowy runway and experiencing an 18-second delay deploying the plane's thrust-reversers--needed at least another 800 feet to stop.
The FAA changes, which require airline compliance by Oct. 1, are expected to result in major impacts on Midway and many of the nation's other older airports with runways that are considered short by modern standards. The airlines could be forced to cancel many flights in bad weather, or if planes are already airborne, divert them to other airports.
According to the FAA's new landing rules, pilots and airline dispatchers will be required to make stopping-distance calculations just prior to the flight's approach for landing. The move is intended to make sure the latest information about weather and runway conditions is factored into the decision.
Under existing rules, the calculations are conducted before takeoff. Because conditions frequently change dramatically during flight, pilots are sometimes forced to choose between attempting a landing under potentially dangerous conditions, or inconveniencing passengers and costing their airline by diverting to a different airport.
The Air Transport Association, which represents the major U.S. airlines, will review the FAA action before commenting, said spokesman David Castelveter. The FAA gave the airlines until Sept. 1 to spell out how they would comply with the new landing rules.
Southwest supports the change because "it allows for the use of actual conditions and aircraft performance input when calculating stopping distance," said Southwest spokeswoman Brandy King. She said the airline is developing a safety program to meet requirements.
About half of all U.S. airlines have insufficient policies to determine whether enough landing distance exists on slick runways, according to the FAA. Landing-distance calculations the airlines use sometimes are at odds with the aircraft performance specifications stated by airplane manufacturers, the FAA added.
The tougher rules are also expected to change the way airports conduct their runway sweeping and de-icing operations to keep the landing surface adequately clean and dry to meet the new standards--and avoid canceling and diverting flights.
Rather than waiting for a break in the flow of air traffic to clean a runway, airport authorities could close runways and delay inbound flights until the runway condition is restored, the FAA's Brown said.
Midway officials reported that aircraft-braking action was good on the night of Dec. 8 both before and after the Southwest plane slid off the runway. But tests conducted for the National Transportation Safety Board after the accident rated the runway condition fair to poor.
Under the new rules, a pilot who is told the runway condition is fair to poor will be expected to assume the runway is only in poor shape when deciding whether to land, Brown said.
Chicago aviation officials "do not expect [the FAA order] will have a major impact on airfield operations at Midway or O'Hare International Airports," said city Department of Aviation spokeswoman Wendy Abrams.