Apollo11
Posts: 24082
Joined: 6/7/2001
From: Zagreb, Croatia
Status: offline
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Hi all,
It appears that AF447 was yet another air disaster due to wrong airspeed readouts (i.e. pitot malfunction)... 
I really don't understand why airplane manufactures don't use GPS as backup when pressure driven pitots show contradicting results?
Also why not using simple ground radar as another instrument for measuring speed?
The GPS is not 100% accurate bt it can give x,y,z position and rough speed - this is all that is needed in emergency when "classic" instruments (for example pitot tubes) contradict and disable autopilot.
BTW, I am also afraid that pilots rely too much on computers and are very confused when they turn OFF (for example autopilot turned off due to contradicting speed readouts and airplane stalled and crashed)... 
quote:
Air France crash pilots lost vital speed data, say investigators
By CNN
Pilots of the Air France flight that crashed in 2009 and plummeted 38,000 feet in just three minutes and 30 seconds, lost vital speed data, France's Bureau of Investigation and Analysis (BEA) said Friday.
The pilots got conflicting air speeds in the minutes leading up to the crash, the interim reports states. The aircraft climbed to 38,000 feet when "the stall warning was triggered and the airplane stalled," the report says.
Aviation experts are asking why the pilots responded to the stall by pulling the nose up instead of pushing it down to recover.
Miles O'Brien, a pilot and aviation analyst, said: "You push down on the wheel to gain air speed, perhaps they (pilots) were getting information that the air speed was too high. Pulling the nose up will exacerbate an aerodynamic stall."
The speed displayed on the left primary flight display were "inconsistent" with those on the integrated standby instrument system (ISIS), the report says.
The aircraft experienced some "rolling" before stalling and then descending rapidly into the ocean. The descent lasted 3 minutes and 30 seconds and the engines remained operational, said the report. It plunged at 10,912 feet (3,300 meters) per minute.
At the time of the descent, the two co-pilots and captain were in the aircraft cockpit.
Richard Quest, CNN's aviation expert, said: "For whatever reason the aircraft speed sensors failed and the A330 went into a high altitude stall. The pilot's actions were unable to recover the aircraft and some might say, made the bad situation worse.
"The actual falling from the sky will have been horrific. This plane fell out of the sky."
All 228 people aboard the Airbus A330 Flight 447 from Rio de Janeiro to Paris were killed on June 1, 2009.
The pilots lost contact with air traffic controllers while flying across an area of the Atlantic Ocean known for constant bands of severe turbulence.
Air crash investigators at the Paris-based BEA have been working on the theory that the speed sensors, known as pitot tubes or probes, malfunctioned because of ice at high altitude.
Since the accident, Air France has replaced the pitots on its Airbus fleet with a newer model, Agence-France Presse reports.
The report quotes the pilots -- who were not named -- and reveals that they were aware of the storm ahead.
In tech's golden age, why can't black boxes do more?
Four hours and six minutes into the flight, one of the co-pilots, referred to as PF, called the cabin crew, telling them that: "In two minutes we should enter an area where it'll move about a bit more than at the moment, you should watch out... I'll call you back as soon as we're out of it."
The report said that four hours and 10 minutes into the flight: "The autopilot [and] then [the] auto-thrust disengaged," and co-pilot PF said: "I have the controls." The report said the stall warning sounded twice in a row.
A short time later the other co-pilot, referred to as PNF said: "So, we've lost the speeds." A second later the stall warnings sounded again the report said.
At about this time, "The speed displayed on the left side increased sharply," the report said. The aircraft was then at an altitude of about 37,500 feet.
The report said that at this time co-pilot PNF tried several times to call the captain back to the cockpit.
The aircraft then climbed to 38,000 feet and at around four hours 11 minutes and 40 seconds into the flight, the captain re-entered the cockpit. During the following seconds all of the recorded speeds became invalid and the stall warning stopped, the report said.
Co-pilot PF said: "I don't have any more indications," and the co-pilot PNF said "we have no valid indications."
About a minute later co-pilot PF said: "We're going to arrive at level one hundred." This is a height of 10,000 feet. About fifteen seconds later, the data recorder indicate "simultaneous inputs by both pilots on the sidesticks."
The recordings stopped at four hours 14 minutes and 28 seconds into the flight. A full investigation into the crash is expected next year.
Air France said in a written statement: "It appears... that the initial problem was the failure of the speed probes which led to the disconnection of the autopilot and the loss of the associated piloting protection systems. The crew demonstrated a totally professional attitude and were committed to carrying out their task to the very end and Air France wishes to pay tribute to them."
Airbus, manufacturers of the A330, said: "The BEA's work constitutes a significant step towards the identification of the complete chain of events that led to the tragic accident. Airbus is committed to continuing to provide support to the BEA investigation with the objective of identifying all potential lessons to be learnt," according to the Press Association.
Earlier this week French air crash investigators said they would be able to identify two bodies recovered this month from the crash site. The recovery team is now working on retrieving all the bodies, French officials have said.
In early May search teams found the crucial "data recorders" from the wreck site, estimated to lie at a depth of between 2,000 to 4,000 meters (6,562 to 13,124 feet).
quote:
3.5 minutes of terror: Air France crash dropped at 10,000 feet a minute
By Telegraph UK
Passengers on an Air France flight plunged for three and a half minutes before crashing into the Atlantic, killing all 228 on board, after it lost speed and stalled while the main pilot was resting, the first evidence from black boxes has found.
AF447's junior pilot battled to save the Rio de Janeiro to Paris flight, as the second pilot tried to rouse the captain shortly after the plane had begun its fateful descent in a tropical storm.
According to flight recorder data, the younger of the two men, Pierre-Cédric Bonin, 32, angled the jet's nose higher, a position the aircraft maintained until its final impact, after inconsistent speed readings confused the plane.
Aviation experts asked why the pilot kept giving nose-up inputs when the plane was in a stall, given that one normally puts the nose down to recover speed and regain control.
All 228 people on board – including crew – died after the Airbus hurtled into the Atlantic at a speed of 180 feet a second in the worst disaster in Air France's history.
David Robert, 37, the second pilot, had begun anxiously calling for their more experienced captain after autopilot suddenly cut out four hours after take-off. Captain Marc Dubois, returned a minute and a half later, but never retook control of the plane – instead leaving the flying to his assistants.
Captain Dubois, 58, had clocked up 11,000 flying hours over his airline career, while his more junior counterparts had 6,500 and 2,900 hours respectively.
Air France yesterday praised the "three skilled pilots", saying they "demonstrated a totally professional attitude and were committed to carrying out their task to the very end."
It was standard procedure for the main pilot to take a rest during long haul flights, it added.
The fresh data came after the black boxes were recovered from 12,800 feet beneath the waves and returned to Paris this month two years after the jet disappeared into the night on June 1, 2009.
Releasing preliminary findings yesterday, France's accident investigation office, the Bureau d'Enquêtes et d'Analyses (BEA), said they showed the co-pilots decided to turn slightly to the left to avoid a zone of turbulence, warning cabin crew to expect the plane to "move around" in forthcoming turbulence.
Two minutes later the autopilot disengaged, the instruments began showing that the speed had slowed dramatically and the engine stall warning began to sound.
The BEA said the pilots received inconsistent speed readings for around a minute, with one pilot saying: "We have no valid indications." This suggests there was a problem with the plane's speed sensors, so-called Pitot tubes that an earlier preliminary investigation had indicated might have contributed to the crash.
The pilots responded by pulling up the nose of the aircraft, triggering a stall warning in the cockpit.
According to the BEA, the co-pilots continued to increase the angle of climb, rising rapidly from 35,000 feet to 37,500 feet. When a third stall warning sounded, they continued to pull back on the controls with the engines set to full thrust and rose to about 38,000 feet, where the plane entered a stall.
With the plane's nose still pointed up about 15 degrees, the jet began falling at about 10,000 feet a minute, rolling left and right. Almost one minute into the stall, the pilots had reduced engine thrust and tried pushing down on the controls to lower the nose.
Airspeed indications returned and the alarm sounded again as the stalled aircraft picked up some speed, but the plane never recovered.
The BEA said at no time was there engine failure: "The engines were operating and always responded to crew commands."
Air France and Airbus are facing manslaughter charges following the crash and a judicial investigation led by Paris judges is under way.
The BEA said its preliminary findings from the flight recorders had not yet established a cause for accident, which would come only after "painstaking" analysis of the data. A second report is due in July.
Mr Dubois was among some 51 victims retrieved from the Atlantic following the June 1, 2009 crash.
The victims included five Britons and three Irish doctors.
Robert Soulas, whose daughter and son-in law died in the Air France crash, said: "It's a great moment, because we have been waiting for a long time, so it's a very long period, and so it's possible now to see the result of this investigation, and so it's very important for us."
His wife Courinne added: "We are in a horror movie... so, for my part, I would have preferred not to talk about it, that we could leave them in peace, and that we could be left with an image different from reality, from what we will be told (after recorders have been analysed). Bring back the bodies, identify them or not.... either way, we are left traumatised. And now even more so."
Leo "Apollo11"
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 Prior Preparation & Planning Prevents Pathetically Poor Performance! A & B: WitW, WitE, WbtS, GGWaW, GGWaW2-AWD, HttR, CotA, BftB, CF P: UV, WitP, WitP-AE
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