11 June 2009

AF 447 Crash (Update)

The FAB reported on Jun 9th, that a total of 41 bodies had been recovered. The FAB indicates, that the weather may change and hamper recovery activity in the coming days. Efforts currently concentrate on the locations where bodies have been detected. Airbus Industries said in an internal e-mail leaked to the public, that there is no evidence of any electrical failure as had been initially claimed by Air France, no evidence of loss of flight instrument displays and no evidence of an ADIRU malfunction as had happened in the Qantas incidents (Qantas uses a different ADIRU manufacturer than Air France).

The ACARS messages as available all indicate unreliable airspeed, although some messages suggest further aircraft evolution and/or crew actions. The last message (cabin vertical speed) indicates a loss of cabin pressure at a rate greater than 1800 feet per minute, which remains to be explained. 3 types of pitot tubes are available, 2 from Thales (BA and AA/Standard) as well as one from Goodrich. The standard Thales pitot tube AA was used on Air France's A330 F-GZCP. The BA type was developed to enhance water drainage encountered during heavy rain conditions during takeoff or landing.

According to the French pilots' union Air France have agreed to dispatch A330 and A340 aircraft only with at least two of the three pitot tubes retrofitted with the new type starting coming Tuesday.

The FAB reported on Jun 10th, that the worsening weather did not impact the recovery operations although search planes were directed at other routes with more favourable weather conditions. The French submarine "Emerau" and the French helicopter carrier and command ship "Mistral" have arrived at the search area. After taking specialist sonar and sensor equipment from the US on board both ships will start the search for the black boxes.

The flight recorders from Flight 447 are now the subject of a massive international search because they could hold the answer to the cause of the crash.
A French nuclear submarine and other vessels now searching for the recorders are focusing on its underwater locator beacon -- a device that sends acoustic pulses, or "pings," to searchers.

The U.S. Navy is contributing two high-tech acoustic devices to locate the pings that will be attached to French tug boats and can search to a maximum depth of 20,000 feet (6,100 meters).
The batteries that power the locator beacon are designed to last for about 30 days, though the boxes are designed to keep the contents safe for much longer.

While the wreckage is believed to be about 15,000 feet (4,600 meters) deep, amid underwater mountains and mixed in with tons of sea trash, experts have said they are confident the recorders can be found.

Airspeed sensors like those on the downed plane are susceptible to icing in high-altitude storms. They can affect the stability of an aircraft, particularly if it is on autopilot; one wrong reading can make the autopilot shift the plane into a wrong direction or wrong speed.

Interpol, the international police organization, said Tuesday it is helping to coordinate efforts by a number of countries to identify the crash victims, who came from 32 countries.

"In any major tragedy, a coordinated effort by the international community will significantly speed up the victim recovery and identification process and Interpol is uniquely placed to provide this support to each of our member countries involved," Secretary-General Ronald Noble said.

PARIS, France (CNN) -- There should be no assumed link between on-board speed sensors and the crash of Air France Flight 447 into the Atlantic Ocean last week, the airline's chief executive said Thursday.

Air France CEO Pierre-Henri Gourgeon, shown at a June 1 news conference, says probing the crash will be tough.

"I am not convinced that the sensors are the cause of the accident," said Air France Chief Executive Pierre-Henri Gourgeon.
Still, he said, the airline will continue with a program, begun just days before the crash, to replace the sensors on its Airbus A330s, the same type of plane that crashed June 1.
The sensors on the doomed plane hadn't yet been replaced, he said.

"Airbus and the European Aviation Safety Agency maintain that the A330/A340s are safe with any one of the three types of existing sensors," Gourgeon told reporters in France.
Air France has promised that no Airbus A330 or A340 will take off unless at least two of its three Pitot tubes have been replaced. The tubes are an instrument contained in the speed-sensing system.

Gourgeon cautioned journalists that "as for the assumptions made by some of the media, they are pure speculation." He did not elaborate.

Details of the ACARS messages have become available on June 5th and suggest following events while the airplane was in cruise (note, there is no message regarding electrics, hydraulics or engine problems):

Autothrust off

Autopilot off

FBW alternate law

Rudder Travel Limiter Fault

TCAS fault due to antenna fault

Flight Envelope Computation warning

All pitot static ports lost

Failure of all three ADIRUs

Failure of gyros of ISIS (attitude information lost)

ADIRUs Air Data disagree

Flight Management, Guidance and Envelope Computer fault

PRIM 1 fault

SEC 1 fault

Cabin Pressure Controller fault (cabin vertical speed)

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