A new radar system designed to keep track of taxiing airplanes might have prevented Monday's fiery ground collision near Detroit if it had been operating there, the national spokesmen for air traffic controllers and airlines said.
The Airport Surface Detection Equipment or ASDE-3, a $3 million radar system that was supposed to begin operating this month at Pittsburgh but has developed technical problems, is scheduled to be installed over the next three years at 29 other major airports around the country, including Detroit.
Baltimore-Washington International Airport is scheduled to get one in March 1992.
"A working ASDE-3 definitely could have prevented" the collision, which occurred in fog that limited visibility to one-quarter mile, said Tony Dresden, a spokesman for the National Air Traffic Controllers Association, the union representing control-tower employees. "The controllers could have seen what was going on that situation."
Tim Neale of the Air Transportation Association, which represents major airlines, agreed that the ASDE-3 "probably would have helped" avoid the collision between a DC-9 and Boeing 727 on a fog-shrouded runway.
The crash started a fire that killed eight people.
"It's hard to say definitely it would have prevented it because we don't know definitely yet what happened," Mr. Neale said.
He said airlines were unhappy that installation of the new radar units had not occurred more quickly, adding that they were first ordered by the Federal Aviation Administration five years ago.
"It takes them [the FAA] an awful long time to get anything done," he said. "It's not the fault of the people working over there; it's the [procurement] procedures they have to follow."
Meanwhile, the National Transportation Safety Board has been urging the FAA since 1986 to require pilots to repeat in full all tower instructions to hold, take off, cross over runways or enter runways.
Now, pilots are required to confirm receiving the information by saying "Roger" or by giving their airplane identification number, an NTSB spokesman said.
The board has also urged that the FAA launch a major safety study, with the aim of revising runway signs, markings and procedures.
The FAA has not yet issued a final response to those two recommendations.
Controllers at most major airports, including BWI, control all ground movements and rely on pilots to tell them where their aircraft are when visibility is poor, the FAA said. Taxiing pilots, meanwhile, must follow those instructions relying on signs and markings to guide them.
While "the controllers are in charge" when the plane is on the ground, "they expect the pilot to use his reason and judgment," said Duncan B. Pardue, a spokesman for the FAA.
Mr. Dresden, of the air traffic controllers union, said that ground traffic was very heavy at most big airports because of the centralized, hub-and-spoke system adopted by most major airlines for moving passengers.
The ASDE-3 system uses an antenna housed in an 18-foot-diameter, teacup-shaped dome to provide a clear radar picture to the control tower of planes and other vehicles between the ground and an altitude of 200 feet.
The FAA is already looking at an improvement to the system that would automatically signal controllers when two vehicles on the ground are in danger of colliding.