FAA Reviewing System "Issues"
During a heavy downpour the evening before the Kentucky Derby, a
Northwest Airlines DC-9 mistakenly crossed an active runway where
another aircraft was on final approach at Louisville International
Airport.
SDH air traffic controllers said they could not see the DC-9
that had just landed and were, thus, unable to warn it not to cross
that runway, according to the Associated Press.
The new radar system, an Airport Surface Detection Equipment
Model X, or ASDE-X, had just malfunctioned - and not for the first
time, according to controllers.
The ASDE-X system is designed to track aircraft and other
vehicle movement on airport grounds and uses part of the airport's
old system. It has been in the testing phase since its March 11
launch.
There is no backup system.
Federal Aviation Administration spokeswoman Laura Brown denied
any collision danger, but did acknowledge the agency is looking at
"issues" with the Louisville radar system.
"There were no other planes in the immediate vicinity that
presented a potential conflict with the plane on the runway," she
said.
Jeff Gilde, president of the
Louisville chapter of the National Air Traffic Controllers
Association, said the inbound traffic was only about a minute from
landing. Because of both weather and the radar failure, "we would
not have known anything had happened unless two airplanes hit and
there had been an explosion," he said.
Roman Blahoski, a Northwest spokesman, said in a statement the
NWA aircraft had "landed without incident" and was not "involved in
a runway incursion at (the airport). Although the DC-9 aircraft did
cross (the active runway) upon landing ... there were no conflicts
with any other aircraft, and at no time was passenger safety in
jeopardy."
Northwest is cooperating fully with the FAA review, he said.
Gilde wrote the FAA's air traffic manager in Louisville three
days after the incident, saying "we have had a number of very
serious issues with this (radar) system that cannot be ignored." "I
do not need to tell you how lucky we were not to have a
catastrophic event," Gilde said, referring to the Northwest
incident. "This is an unacceptable safety risk, and something needs
to be done to stop this system from being certified until such time
it works properly."
The new technology is not ready for regular use, according to
Gilde and Chuck Morrison, president of the local chapter of the
Professional Airways Systems Specialists, the technicians who
maintain the system.
"I knew that with any new system, we were going to have trouble
with it," Morrison said. But, he said, "We've had a significant
number of unscheduled outages of this system."
At least one other
airport has reported frequent problems with the system, in Seattle,
according to the AP. ASDE-X systems are now operating at airports
in Atlanta, Houston (Hobby), Providence, Seattle/Tacoma, Orlando,
St. Louis, Milwaukee and Hartford and is due to be installed in
Chicago soon.
According to Morrison, there are times when the radar screen
goes blank. At other times planes or vehicles just "drop off the
screen" or are never detected in the first place.
"Whenever you have a storm ... the controller can't see as
well," Morrison said. And "the pilot can't see as well. That's the
time you need the system the most." Instead, controllers were left
without any ground radar, he said. "That's when you have a recipe
for an accident," Morrison said.
Since the radar was activated, the Louisville area has had four
major rain storms and each time the system failed, for different
reasons, he said.
Glide said the rain was coming down so hard that controllers
could see nothing out the tower windows on May 4, the eve of the
Derby. About 6:30 p.m., Northwest Flight 1246 landed on
Louisville's eastern parallel runway, using its entire 7,800
feet.
Pilots then turned the plane around and taxied along a taxiway
that runs parallel to the runway before being instructed by
controllers to turn left toward the terminal onto a runway that was
not in use.
The plane instead turned right for unknown reasons crossing the
runway they had just landed on.
"The pilot did not tell us he crossed the active runway until he
was on the other side of it," Gilde said. The ground radar at that
time? It was "a blue screen - it was blank," he said.
After being notified of the error, the Northwest plane was told
to wait while the second aircraft landed, Gilde said. It then
re-crossed the active runway to the terminal. He said he did not
know what type of plane landed while the Northwest jet waited.
According to Brown, Louisville's ground radar is "still in the
testing phase."
"We are in the process of looking at issues that have come up
during the testing," she said. When there is severe weather
"there's potential for limited use" of the ground radar. But pilots
and controllers still have procedures for talking to each other by
radio and ensuring that instructions are being followed, she
said.
She said that what happened in Louisville "happens very
infrequently anywhere with ASDE-X" and it "generally" performs
better in bad weather than the old one did. The FAA is testing a
"rain mode" for this radar system that would allow it to see
vehicle movement more accurately during heavy rains, she added.
Senator Patty Murray, D-Wash., told a Senate subcommittee
hearing Thursday in Washington that in the last 15 months
controllers in Seattle have filed 480 reports of false targets or
false alarms.
"We would love this system to work," Glide said. "But when it
doesn't, we have to cry foul."