Airport Warning Tests Are Ordered by FAA

WASHINGTON — The government is ordering the immediate testing of airports’ low-altitude warning systems after disclosure that the system was not working on Guam when Korean Air Flight 801 crashed last week.

The Federal Aviation Administration announced Monday that, as a precaution, it “is directing the testing of all of the Minimum Safe Altitude Warning Systems within the next two days.”

There are about 200 of the systems at U.S. airports, designed to issue an alert if a jet is flying too low. Controllers on the ground then warn the pilot.

The National Transportation Safety Board reported Sunday that an error was apparently inserted into the Guam system’s software during an overhaul and it was not working at the time of the Korean Air accident, which killed 226 people. Officials still are not sure when the mistake was introduced or whether there are similar errors in radar software at other airports.

Investigators say the faulty system was not to blame for the crash. Nevertheless, they say, a properly working system could have allowed air traffic controllers to direct the pilot of the Boeing 747 to pull the jumbo jet to a higher altitude as he approached Guam International Airport. The FAA is also using data taken from Flight 801 to simulate the jet’s route and figure out when the alert should have been given, said George Black, an NTSB member.