Communications breakdown could became the reason
of air crashes
Air traffic controllers in the Los Angeles
area lost voice contact with 800 planes on
Tuesday, allowing 10
to fly too close together,
after a radio system shut down because a routine
inspection was skipped, the Federal Aviation
Administration said Wednesday.
Angeles Air Route Traffic Control Center, caused
widespread disruptions. The system shut down
while 800 planes were in the air, and forced
delays for 400 flights and the cancellations of
While there were no accidents, there were five
incidents in which planes flew closer than rules
In two cases, "controllers could see the two
data blocks superimposed on each other," said
Doug Church, a spokesman for the controllers
union, the National Air Traffic Controllers
Association, said, referring to the block of
letters and numbers
on the radar screen that locates a plane.
"It was about thelongest 12 seconds of their
life," he said.
Rick Day, the acting vice president of
the F.A.A.'s Air Traffic Organization, said that the airplanes
were supposed to be separated by five nautical miles laterally,
or 2,000 feet in altitude. While Mr. Church, the union
spokesman, said one set of planes came within a mile of
each other, the aviation agency said two pairs of planes
had come within two miles laterally and were separated
by 1,100 feet and 1,400 feet. But he added that in January,
standards will change and planes will be allowed to come
within 1,000 feet in altitude of each other, informs the
According to News10, Air travel on the West Coast remained
snarled well into Wednesday morning after a radio failure
grounded planes for more than three hours Tuesday night.
On Tuesday afternoon, air traffic controllers at an FAA
control center north of Los Angeles found they could monitor
planes on radar but couldn't talk to them. At about 5
p.m., the FAA decided to ground aircraft at airports in
and around Los Angeles and at other West Coast airports,
including Sacramento International. Planes that were in
the air were allowed to land at those airports.
The FAA fixed the radio problem by about 9 p.m., but by
that time there was a long backlog of delayed flights.
Although there were massive delays and at least one close
call, no accidents occurred during the outage, according
to the Federal Aviation Administration.
Airports most severely affected by the radio failure
were those in Southern California and Las Vegas.
Two separate human errors caused the breakdown in radio
communications that brought Southern California's major
airports to a near-stop on Tuesday and led to at least
five instances where planes came closer to each other
than regulations allow, Federal Aviation Administration
'A loss of communication is a serious matter and it
should not have occurred,' Mr Rick Day, a senior FAA
official, said on Wednesday.
FAA officials said its radio system in Palmdale, in
the Mojave Desert, shut itself down on Tuesday afternoon
because a technician failed to reset an internal clock
- a routine maintenance procedure required every 30
days by the FAA.
Then the back-up system failed, also as a result of
technician error, officials said.
On Tuesday, FAA officials had insisted that the more
three-hour system shutdown
posed no safety risks. But they acknowledged on Wednesday
that they are investigating five incidents in which
planes lost the required separation distance during
the first 15 minutes of the communications breakdown.
In two cases, large airliners came more than twice as
close to small corporate jets as federal guidelines
allow, requiring at least one pilot to take corrective
action, reports AsiaOne.
|FAA Says Fixes Will Prevent
Repeat Of Radio System Failure
FAA officials say they are moving quickly to
ensure there is no repeat of the radio communication
failure that disrupted hundreds of flights in
Southern California this week.
A five-hour shutdown of the voice communications
system Tuesday at the en route ATC center in Palmdale,
Calif., meant flights had to be grounded or diverted
to other airports. The outage caused about 400
delays and about the same number of cancellations.
Radar coverage was never lost, and aircraft were
handed off to other centers.
The agency said it is "aggressively investigating"
the shutdown, and although its systems generally
have greater than 99% reliability, any failure
"is unacceptable because of the inconvenience
to air travelers and cost to the airlines."
The primary voice communication system shut down
at about 5 p.m. Pacific Time, and the secondary
system failed soon after. Operations were restored
gradually when the system was brought back on
line. The Professional Airways Systems Specialists
(PASS) union said only one technician was on duty
at the time of the outage, and an off-duty specialist
had to be brought in to fix the problem.
FAA said the primary system shut down automatically
because a required 30-day maintenance check was
not performed, and the outage would have been
avoided if procedures had been followed correctly.
The secondary system "was not configured
properly to ensure its availability," the
The agency said it will review its maintenance
checklists and protocols to make sure maintenance
procedures are up to date and are being followed.
It will add new feature to prevent service disruptions
if periodic maintenance is not performed.
A PASS official told The DAILY that this problem
has occurred at other en route centers, and FAA
is working to install a patch to correct an anomaly
in a recent system upgrade. The PASS official
said the new system's synchronization expires
every 50 days, and it does not automatically reset
An American spokeswoman said the FAA problems
contributed to a "crazy day"
on Tuesday. American had 31 flights either diverted
or canceled due to the voice communications outage,
and 44 flights were diverted because of thunderstorms
in the Dallas/Fort Worth area.