Datos objetivos entorno al accidente del AF447 a fecha de hoy

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Description

BEAOn 1 June 2009, an Air France Airbus A330-203 disappeared over the Atlantic Ocean while transiting the ITCZ, a belt of thunderstorm activity. The accident is the subject of an on-going investigation by the French BEA. On 27 May 2011, the BEA published an Update on the Investigation based on analysis of the flight recorders.

The update describes in a factual manner the chain of events that led to the accident and presents newly established facts. A further Interim Report is scheduled to be published towards the end of July 2011.

Synopsis

This is the Summary from the Interim Report 2 published by the BEA:

"On 31 May 2009, flight AF447 took off from Rio de Janeiro Galeão airport bound for Paris Charles de Gaulle. The airplane was in contact with the Brazilian ATLANTICO ATC centre on the INTOL – SALPU – ORARO route at FL35035,000 feet
10.668 km. There were no further communications with the crew after passing the INTOL point. At 2 h 10, a position message and some maintenance messages were transmitted by the ACARS automatic system. Bodies and airplane parts were found from 6 June 2009 onwards by the French and Brazilian navies."

Investigation

The French BEA (Bureau d'Enquêtes et d'Analyses pour la sécurité de l'aviation civile) is conducting an on-going investigation into the accident. Press releases have been issued regularly concerning the progress of the investigation and the latest information, including preliminary and interim reports, is available, in English as well as French, on the BEA website.

Interim Report 2

On 17 December 2009, the BEA published a second Interim Report as an update on the Technical Investigation as of 30 November 2009.

It reported that the investigation had continued, focusing on:

  • "the elements of wreckage recovered
  • the meteorological situation
  • the maintenance messages transmitted by ACARS
  • the certification and continuing airworthiness of the Pitot probes
  • events where speed inconsistencies were encountered in cruise."

The Report goes on to state that "The results of this work have been integrated into this report. It has made it possible to complete the paragraphs of the first report published on 2 July 2009 and to introduce new paragraphs" and advises that the new report includes safety recommendations. It notes that "at this stage, in the absence of any data from the flight recorders, the main parts of the airplane and any witness testimony on the flight, the precise circumstances of the accident, and therefore its causes, have still not been determined. The investigative work is continuing with this objective." It is also states that sea search for the flight recorders is currently intended to re-commence in February 2010.

Findings

The Second Interim report, published in December 2009, lists the following findings (New findings established since the Interim Report published on 2 July 2009 appear in blue italics).

  • "The crew possessed the licenses and ratings required to undertake the flight.
  • The airplane possessed a valid Certificate of Airworthiness, and had been maintained in accordance with the regulations.
  • The airplane had taken off from Rio de Janeiro without any known technical problems, except on one of the three radio management panels.
  • No problems were indicated by the crew to Air France or during contacts with the Brazilian controllers.
  • No distress messages were received by the control centres or by other airplanes.
  • There were no satellite telephone communications between the airplane and the ground.
  • The last radio exchange between the crew and Brazilian ATC occurred at 1 h 35 min 15. The airplane was arriving at the edge of radar range of the Brazilian control centres.
  • At 2 h 01, the crew tried, without success for the third time, to connect to the Dakar ATC ADS-C system.
  • Up to the last automatic position point, received at 2 h 10 min 34, the flight had followed the route indicated in the flight plan.
  • The meteorological situation was typical of that encountered in the month of June in the inter-tropical convergence zone.
  • There were powerful cumulonimbus clusters on the route of AF447. Some of them could have been the centre of some notable turbulence.
  • An additional meteorological analysis shows the presence of strong condensation towards AF447's flight level probably associated with convection phenomena.
  • The precise composition of the cloud masses above 30,000 ft9,144 m is little known, in particular with regard to the super-cooled water/ice crystal diving, especially with regard to the size of the latter.
  • Several airplanes that were flying before and after AF447, at about the same altitude, altered their routes in order to avoid cloud masses.
  • Twenty-four automatic maintenance messages were received between 2 h 10 and 2 h 15 via the ACARS system. These messages show an inconsistency in the measured speeds as well as the associated consequences.
  • Before 2 h 10, no maintenance messages had been received from AF447, with the exception of two messages relating to the configuration of the toilets.
  • Twenty-one messages present on the CFR are caused or can be caused by anemometric problems;
  • None of the messages present in the CFR indicate loss of displays or inertial information (attitudes);
  • The operator's and the manufacturer's procedures mention actions to be undertaken by the crew when they have doubts as to the accuracy of the speed indications,
  • The last ACARS message was received towards 2 h 14 min 28,
  • The flight was not transferred between the Brazilian and Senegalese control centres,
  • Between 8 h 00 and 8 h 30, the first emergency alert messages were sent by the Madrid and Brest control centres,
  • The first bodies and airplane parts were found on 6 June,
  • The elements identified came from all over the airplane,
  • The oxygen masks had not been released; there had been no in-flight depressurisation,
  • All of the life jackets that were found were still in their containers,
  • The airplane's flaps were retracted at the time of the impact with the water,
  • Three of the eleven cabin crew seats were found; they were not in use at the time of the impact,
  • Examination of all of the debris confirmed that the airplane struck the surface of the water pitch-up, with a slight bank and at a high vertical speed,
  • Analysis of thirteen previous events shows that:
    • they occurred in air masses that were highly unstable and the seat of deep convection phenomena;
    • autopilot disengaged in all of the cases;
    • the maximum continuous invalid recorded speed duration was three minutes and twenty seconds;
    • the uncommanded altitude variations remained within a range of more or less one thousand feet,
    • the airplane always remained within its flight envelope
  • The probes that equipped F-GZCP met requirements that were stricter than the certification standards,
  • On 30 March 2009, analysis of previous events had not led EASA to make mandatory a change of the probes on the Airbus A330 / A340 fleet."

Recommendations

The Report made six Recommendations, four in respect of flight recorders and two in respect of aircraft certification. The two paragraphs containing the reasons for the recommendations and their full text are reproduced below:

Flight Recorders

"The investigation into the accident to AF447 confirms the importance of data from the flight recorders in order to establish the circumstances and causes of an accident and to propose safety measures that are substantiated by the facts. As in other investigations, it also brings to light the difficulties that can be encountered in localizing, recovering and reading out the recorders after an accident in the sea. These difficulties raise questions about the adequacy of the means currently in use on civil transport aircraft for the protection of flight data with the technological possibilities and the challenges that some accidents represent, in particular those that occur over the sea. In the context of this investigation, the BEA thus formed an international working group in order to examine the various techniques that can be employed to safeguard flight data and/or to facilitate localisation of the wreckage and recovery of the flight recorders. This working group dedicated itself to analysing each field as completely as possible, from the transmission of flight data by satellite to new ULB technologies and it settled on three additional areas for significant improvements in safety: increasing the transmission time and range of the ULB beacons, the sending of data on initialisation and the installation of deployable recorders. This work was presented on 19 November 2009 to the ICAO Air Navigation Commission.

On the basis of this work, le BEA recommends that EASA and ICAO:

  • extend as rapidly as possible to 90 days the regulatory transmission time for ULB's installed on flight recorders on airplanes performing public transport flights over maritime areas;
  • make it mandatory, as rapidly as possible, for airplanes performing public transport flights over maritime areas to be equipped with an additional ULB capable of transmitting on a frequency (for example between 8.5 kHz and 9.5 kHz) and for a duration adapted to the pre-localisation of wreckage;
  • study the possibility of making it mandatory for airplanes performing public transport flights to regularly transmit basic flight parameters (for example position, altitude, speed, heading).

In addition, the BEA recommends that ICAO:

  • ask the FLIRECP group to establish proposals on the conditions for implementing deployable recorders of the Eurocae ED-112 type for airplanes performing public transport flights.

Certification

Examination of reported UAS events in cruise has shown that the majority of them occurred outside of the envelope defined in Appendix C. In fact, the certification criteria are not representative of the conditions that are really encountered at high altitude, for example with regard to temperatures. In addition, it appears that some elements, such as the size of the ice crystals within cloud masses, are little known and that it is consequently difficult to evaluate the effect that they may have on some equipment, in particular the Pitot probes. In this context, the tests aimed at the validation of this equipment do not appear to be well-adapted to flights at high altitude.

Consequently, the BEA recommends that EASA:

  • undertake studies to determine with appropriate precision the composition of cloud masses at high altitude, and
  • in coordination with the other regulatory authorities, based on the results obtained, modify the certification criteria."

To view the Interim Report No 2 in full, click here

Related Articles

  • A332 – Airbus A330-200
  • Fly-By-Wire – Fly-by-Wire is the generally accepted term for those flight control systems which use computers to process the control movements made by the pilot, or autopilot, and send appropriate electrical signals to the flight control surface actuators. This arrangement replaces mechanical linkage and means that the pilot inputs do not directly move the control surfaces. Instead, inputs are read by a computer that in turn decides how to move the control surfaces to best achieve what the pilot wants.
  • ITCZ – The Inter Tropical Convergence Zone, or ITCZ, is the belt of low pressure girdling the Earth, near the equator, where the trade winds of the Northern and Southern Hemispheres come together. It is formed by the vertical ascent of warm, moist air from the latitudes above and below the equator. As the air ascends it cools, releasing the accumulated moisture in what can be an almost continuous series of thunderstorms.
  • ACARS – An Aircraft Communications, Addressing and Reporting System (ACARS) is a digital datalink system for transmission of messages between aircraft and ground stations via VHF radio or satellite. ACARS has been in use in the airline industry since 1978.
  • BEA – Bureau d'Enquêtes et d'Analyses (France). "The BEA is the official French organisation responsible for technical investigations of civil aviation accidents and incidents. Created in 1946, The BEA is attached to the Ministry of Transportation. The BEA carries out investigations and issues its reports in a completely independent manner."

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