A second consequence of the reconfiguration into ALT2 was that the stall protection no longer operated, whereas in normal law, the aircraft's flight-management computers would have acted to prevent such a high angle of attack.

[f] In addition to the routine position reports, F-GZCP's centralized maintenance system sent a series of messages via ACARS in the minutes immediately prior to its disappearance.

[111] With the aircraft under the control of its automated systems, one of the main tasks occupying the cockpit crew was that of monitoring the progress of the flight through the ITCZ, using the on-board weather radar to avoid areas of significant turbulence.

An Air France spokesperson told L'Express that "no hope for survivors" remained,[119][120] and French President Nicolas Sarkozy announced almost no chance existed for anyone to have survived.

[124][125] Brazilian vice-president José Alencar (acting as president since Luiz Inácio Lula da Silva was out of the country) declared three days of official mourning.

Initially, media (including The Boston Globe, the Los Angeles Times, and the Chicago Tribune) cited unnamed investigators in their reporting that the recovered bodies were naked, which implied the plane had broken up at high altitude.

French Bureau of Enquiry and Analysis for Civil Aviation Safety (BEA) chief Paul-Louis Arslanian said that he was not optimistic about finding them since they might have been under as much as 3,000 m (9,800 ft) of water, and the terrain under this portion of the ocean was very rugged.

[167][171][175] The search area had been drawn up by oceanographers from France, Russia, Great Britain and the United States combining data on the location of floating bodies and wreckage, and currents in the mid-Atlantic in the days immediately after the crash.

Phase 4 of the search operation started close to the aircraft's last known position, which was identified by the Metron study as being the most likely resting place of flight 447.

[185] The debris was found lying in a relatively flat and silty area of the ocean floor (as opposed to the extremely mountainous topography originally believed to be AF447's final resting place).

[187] The debris field was described as "quite compact", measuring 200 by 600 metres (660 by 1,970 ft) and a short distance north of where pieces of wreckage had been recovered previously, suggesting the aircraft hit the water largely intact.

[192][193] Île de Sein arrived at the crash site on 26 April, and during its first dive, the Remora 6000 found the flight data recorder chassis, although without the crash-survivable memory unit.

[206] As part of the criminal investigation, the DGSE (the external French intelligence agency) examined the names of passengers on board for any possible links to terrorist groups.

At that time, the investigation had established only two facts—the weather near the aircraft's planned route included significant convective cells typical of the equatorial regions, and the speeds measured by the three pitot tubes differed from each other during the last few minutes of the flight.

[2]: 122 [226] The problems primarily occurred in 2007 on the A320, but awaiting a recommendation from Airbus, Air France delayed installing new pitot tubes on A330/A340 and increased inspection frequencies in these aircraft.

On 20 December 2010, Airbus issued a warning to roughly 100 operators of A330, A340-200, and A340-300 aircraft regarding pitot tubes, advising pilots not to re-engage the autopilot following failure of the airspeed indicators.

"[253] The BEA subsequently released its final report on the accident, and Appendix 1 contained an official CVR transcript that did not include groups of words deemed to have no bearing on flight.

[257] A brief bulletin by Air France indicated, "the misleading stopping and starting of the stall-warning alarm, contradicting the actual state of the aircraft, greatly contributed to the crew's difficulty in analyzing the situation.

In May 2011, Wil S. Hylton of The New York Times commented that the crash "was easy to bend into myth" because "no other passenger jet in modern history had disappeared so completely—without a Mayday call or a witness or even a trace on radar."

"[260] In a July 2011 article in Aviation Week, Chesley "Sully" Sullenberger was quoted as saying the crash was a "seminal accident" and suggested that pilots would be able to better handle upsets of this type if they had an indication of the wing's angle of attack (AoA).

[262] Following its investigation, the BEA recommended that the European Aviation Safety Agency and the FAA should consider making an AoA indicator on the instrument panel mandatory.

On 6 December 2011, Popular Mechanics published an English translation of the analysis of the transcript of the CVR controversially leaked in the book Erreurs de Pilotage.

It provides an explanation for most of the pitch-up inputs by the pilot flying, left unexplained in the Popular Mechanics piece: namely that the flight director display was misleading.

"[268] Against this backdrop of confusing information, difficulty with aural cognition (due to heavy buffeting from the storm, as well as the stall) and zero external visibility, the pilots had less than three minutes to identify the problem and take corrective action.

[o] In the first incident, an Air France A340-300 (F-GLZL) en route from Tokyo to Paris experienced an event at 31,000 feet (9,400 m), in which the airspeed was incorrectly reported and the autopilot automatically disengaged.

[286] In the second incident, an Air France A340-300 (F-GLZN) en route from Paris to New York encountered turbulence followed by the autoflight systems going offline, warnings over the accuracy of the reported airspeed, and 2 minutes of stall alerts.

The NTSB also examined a similar 23 June 2009 incident on a Northwest Airlines flight from Hong Kong to Tokyo,[287] concluding in both cases that the aircraft operating manual was sufficient to prevent a dangerous situation from occurring.

[302] A one-hour documentary entitled Lost: The Mystery of Flight 447 detailing an early independent hypothesis about the crash was produced by Darlow Smithson in 2010 for Nova and the BBC.

Without data from the black boxes, an independent panel of experts analyzed ACARS messages among weather patterns and limited debris data to postulate that supercooled water blocked pitot tubes, causing most automatic systems to shut down, before the information overload combined with auto-thrust not adjusting the indicated thrust level of the thrust levers caused crew to neglect increasing power, with automatic systems decreasing the capability of pilots to handle the stall.

[303][304][305][306] On 16 September 2012, Channel 4 in the UK presented Fatal Flight 447: Chaos in the Cockpit, which showed data from the black boxes including an in-depth re-enactment.