The manned submarine Nautileat, seen here in a file photo,
is heading from the Azores and will be in the search zone
for the missing Air France plane by June 12. Photo by
Airspeed instruments on Air France Flight 447 were not
replaced as the maker recommended before the plane crashed in
turbulent weather, the French agency investigating the disaster
The French accident investigation agency, BEA, found the
doomed plane received inconsistent airspeed readings by
different instruments as it struggled in a massive
thunderstorm on its flight from Rio de Janeiro to Paris with
228 people aboard.
No confirmed debris from the aircraft has been found and
without its black box recorders, aviation investigators have
little information to help them determine what caused the
Airbus had recommended to all its airline customers that they
replace speed-measuring instruments known as Pitot tubes on
the A330, the model used for Flight 447, said Paul-Louis
Arslanian, the head of the agency.
"They hadn't yet been replaced" on the plane that crashed,
said Alain Bouillard, head of the French investigation. Air
France declined immediate comment.
Arslanian cautioned that it is too early to draw conclusions
about the role of Pitot tubes in the crash, saying that "it
does not mean that without replacing the Pitots that the A330
He told a news conference at the agency's headquarters, near
Paris that the crash of Flight 447 also does not mean similar
plane models are unsafe, adding that he told family members
not to worry about flying.
Airbus had made the recommendation for "a number of reasons,"
The investigation chief played down the idea that terrorism
was involved in the crash, saying "We can't completely close
the door at the present time but it seems incoherent with the
first facts we have established."
The Pentagon has said there are no signs of terrorism.
Brazil's defense minister said the possibility was never
considered. French Foreign Minister Bernard Kouchner agreed
that there is no evidence supporting a "terrorism theory,"
but said "we cannot discard that for now."
The investigation is increasingly focused on whether external
instruments may have iced over, confusing speed sensors and
leading computers to set the plane's speed too fast or slow -
a potentially deadly mistake in severe turbulence.
Pitot tubes, protruding from the wing or fuselage of a plane,
feed airspeed sensors and are heated to prevent icing. A
blocked or malfunctioning Pitot tube could cause an airspeed
sensor to work incorrectly and cause the computer controlling
the plane to accelerate or decelerate in a potentially
Air France has already replaced the Pitots on another Airbus
model, the 320, after its pilots reported similar problems
with the instrument, according to an Air France air safety
report filed by pilots in January and obtained by The
The report followed an incident in which an Air France flight
from Tokyo to Paris reported problems with its airspeed
indicators similar to those believed to have been encountered
by Flight 447. In that case, the Pitot tubes were found to
have been blocked by ice.
"Following similar problems frequently encountered on the
A320 fleet, preventative actions have already been decided
and applied," the safety report says. The Pitots on all Air
France's A320s were retrofitted with new Pitots "less
susceptible to these weather conditions."
The same report says Air France decided to increase the
inspection frequency for its A330 and A340 jets' Pitot tubes,
but that it had been waiting for a recommendation from Airbus
before installing new Pitots.
Investigators are relying on 24 messages the plane sent
automatically during the last minutes of the flight to try to
locate the wreckage.
The signals show the plane's autopilot was not on, officials
said, but it was not clear if the autopilot had been switched
off by the pilots or had stopped working because it received
conflicting airspeed readings.
Arslanian said investigators are searching a zone of several
hundred square miles (square kilometers) for the debris.
As no confirmed wreckage has been found, concern has grown
about whether searchers were even looking in the right place.
Brazilian air force spokesman Col. Jorge Amaral told
reporters in Recife it was patrolling the area with 14 planes
and three ships.
"We are alert for everything and are certain today's
operation's will provide results," he said.
Visibility and weather conditions have improved in the search
area, but debris spotted earlier on the ocean's surface may
have sunk by now.
Air force Brig. Gen. Ramon Cardoso told reporters late Friday
that the air force would not have the means of finding debris
once it had sunk.
Earlier, he insisted the debris spotted - an airplane seat, a
slick of kerosene and other pieces - was from the plane. But
he confirmed that Brazilian searchers had yet to recover any
of the material. Searchers did not pursue the debris reports
then because priority was given to the hunt for survivors or
Meanwhile, a German government-owned satellite spotted debris
in the Atlantic on Wednesday, German Aerospace Center
spokesman Andreas Schutz said, but he added it was unclear
whether the material came from the plane.
The flight disappeared nearly four hours after takeoff,
killing all on board. It was Air France's deadliest plane
crash and the world's worst commercial air accident since
The head of France's weather forecasting agency, Alain
Ratier, said weather conditions at the time of the flight
were not exceptional for the time of the year and region,
which is known for violent stormy weather.
On Thursday, European plane maker Airbus sent an advisory to
all operators of the A330 reminding them of how to handle the
plane in conditions similar to those experienced by Flight
Peter Goelz, a former managing director of the National
Transportation Safety Board, said that advisory and the Air
France memo about replacing flight-speed instruments
"certainly raises questions about whether the Pitot tubes,
which are critical to the pilot's understanding of what's
going on, were operating effectively."
Arslanian said it is vital to locate a small beacon called a
"pinger" that should be attached to the cockpit voice and
data recorders, now presumed to be deep in the Atlantic.
"We have no guarantee that the pinger is attached to the
recorders," he said.
Holding up a pinger in the palm of his hand, he said: "This
is what we are looking for in the middle of the Atlantic
Investigators are trying to determine the location of the
debris in the ocean based on the height and speed of the
plane at the time the last message was received. Currents
could also have scattered debris far along the ocean floor,
President Barack Obama said at a news conference with French
President Nicolas Sarkozy Saturday that the United States had
authorized all of the U.S. government's resources to help
investigate the crash.
Arslanian said U.S. forces have lent the inquiry acoustic
systems, which will be fitted to two naval vessels. That is
in addition to France's Emeraude submarine and the high-tech
equipment being send to the region by French marine research
Laurent Kerleguer, an engineer specialized in the ocean floor
working with the investigation team, said the zone seen as
the most likely site of the debris was 15,112 feet (4,606
meters) at its deepest point and 2,835 feet (864 meters) at
France's submarine, to arrive next week, will try to detect
signals from the black boxes, said military spokesman