WASHINGTON
The captain of Continental Airlines Flight 1404 stopped using
the Boeing 737's right rudder about four seconds before a 52 mph
gust hit the plane's tail. The wind caused the plane to
"weathervane" -- turn until its nose was pointed into the wind.
Contributing to the accident was the failure by the air traffic
control system to provide the pilots with key wind information, and
the airline industry's failure to incorporate high wind gusts into
pilot training for takeoff in crosswind conditions, the board said.
The plane with 110 passengers and five crew members was in the
midst of a takeoff roll at Denver International Airport on Dec. 20,
2008 when it suddenly veered left off a runway, rumbled across a
frozen field, broke into pieces and burned.
No one was killed, but six people were seriously injured and
dozens more were treated for minor injuries. Board members praised
flight attendants for getting everyone off the plane before the
fire entered the passenger cabin.
The board emphasized that although there was a brief moment in
which the captain could have prevented the accident, he had several
factors working against him. Most importantly, the board said that
if the captain had been told by the air traffic controller who
cleared the flight for takeoff that there had been guts as high as
46 mph recorded by one of two sensors closest to the runway, it's
possible he would have waited until the wind had died down or
requested a different runway.
The controller told pilots there was a crosswind of 31 mph. He
didn't mention gusts. The reading was from the sensor closest to
the departure end of the runway, which was the one controllers were
instructed to use.
Continental's guidance to 737 pilots was not to take off in
crosswinds exceeding 38 mph.
Board member Robert Sumwalt noted that winds elsewhere at the
airport that day were much lighter, and that the plane that took
off on the same runway immediately before Flight 1404 experienced
no problems. Flight 1404 just happened to be going down the runway
at the very instant there was an unusually strong gust.
"This was the perfect wind storm," Sumwalt said.
The captain had twice applied the plane's right rudder during
the first 12 seconds of the takeoff roll to correct its direction
back to the right. But when a gust caused the plane to swing
violently to the left, he reached instead for the tiller, which
turns the nose wheel and was of no use under the circumstances,
investigators said.
Mike Wilson, a software developer from Boulder who was on the
plane, said he still suffers from panic attacks whenever planes
he's on hit turbulence or make rough landings.
"I'm not sure a 50 mph crosswind hitting the side of what would
be the size of a barn door is recoverable," Wilson said of a gust
hitting the side of the plane. "I'm not sure I agree with the idea
that he (the pilot) could have kept it on the runway.
"I guess at the end of the day, any landing or aborted takeoff
you can walk away from is a good one."
The captain had a lot of flying experience and a good safety
record, but he had probably never encountered such strong crosswind
during a takeoff. The board estimated pilots encounter crosswinds
greater than 35 mph about once in 15,000 takeoffs.
Also working against the captain was Continental's flight
simulator training for pilots. It included training for steady high
crosswinds, but not for gusts, investigators said. Due to a quirk
in the simulator's software, the airline thought pilots were being
exposed to gusts, but didn't learn that wasn't the case until the
NTSB's investigation, investigators said. They said that is
probably the case at other airlines.
The board recommended that the Federal Aviation Administration
require airlines to incorporate realistic, gusty winds into their
pilot training.
The board also recommended the FAA conduct research on wind
hazards at Denver and other airports downwind from mountains, and
make that information available to pilots and controllers. NTSB
also wants FAA to require controllers to give pilots more wind
information when they have measurements from more than one source.
Windshear has long been a special concern at the 50-square-mile
Denver airport, located on the plains just east of the Rocky
Mountains. The airport has 32 strategically located wind sensors on
airport grounds.
"In spite of what is perceived to be one of the best wind
sensing systems in the country, things can still sneak through, and
something did sneak through," said NTSB investigator Jack English.
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Continental Airlines issued the following statement:
"Safety is Continental's top priority. We respect the NTSB investigative process and will carefully review today's findings."
