Hi,
maybe the pitot events have always been happening but not reported
Methink it was a know problem .....
In December 1995, Airbus was the finding of a lack of certification of pitot probes: Ice crystals clog the probe which causes severe degradation of calculating flight parameters. This is not a failure, it is a defect of the Pitot probes. According to the regulations in force on the day of the accident, Airbus had an obligation to correct this defect.
Instead of eliminating this defect, Airbus decided to ask the drivers to ensure accountability through the application of the procedure: Following the amendment of the Aircraft Flight Manual for the A330 Airbus, the DGAC imposed in February 2001 a new procedure for pilots titled "Unreliable airspeed conditions" in case of loss or inconsistent speeds measured [AD 2001-069 (B)]. The FAA took over the DGAC AD in June 2001, but noting that this initiative was in response to an "unsafe condition" that could lead to the A330 outside its flight envelope [AD 2001-13-13].
The regulations in force at the time of the accident did not allow a manufacturer to remedy a default by the application of a procedure. In addition, this procedure will be difficult to apply when two precursor events of the accident of Flight 447. Airbus will admit eight months before the crash on 1 June 2009, but nothing will change:
At the end of August and early September 2008, two A330s for Air Caraïbes Atlantique (ACA) encounter severe icing conditions that cause the cruise blocked pitot probes Thales SA and inconsistent measured velocities. During the following October, the Directorate of ACA initiates a meeting at the premises of Airbus in Toulouse. According to the report of the Flight Safety Officer, Airbus engineers have understood at that meeting "the difficulty encountered by the crew for a rapid implementation and effective procedure SPEED INDICATION unreliable and" thinking therefore a modification of checklists.
This procedure made available to drivers to compensate for the lack of pitot probes and "unsafe condition" that resulted was not only inappropriate but also ineffective.
But after the crash of Flight 447, Airbus that did not stop to remind drivers that this procedure should be applied in case of inconsistency of measured velocities (Accident Information Telex No. 2 dated 4 June 2009)
1995/Novembre December 1996: TFU 34.13.00.005 (see document). Airbus made the finding of a lack of certification on pitot probes and Launches Development of the probe Goodrich P / N 0851HL.
"STRONG cumulonimbus (Cb) A HIGH DENSITY OF Containing ICE CRYSTALS CAN BEEN COUNTERED, PARTICULARLY IN THE Intertropical Convergence Zone (ITCZ). IN AN ICY SUCHA AND TURBULENT ATMOSPHERE, THE A / C AIR DATA PARAMETERS (PRESSURE DEPENDENT) MAY BE DEGRADED Severely, Even Though THE PROBE HEATERS WORK Properly.
IT HAS THE CHARACTERISTICS OF THAT Appeared SUCHA AN ENVIRONMENT COULD EXCEED THE WEATHER SPECIFICATIONS FOR THE PITOT PROBES Which ARE CURRENTLY CERTIFIED.
THE WEATHER SPECIFICATIONS (ICING / LIQUID WATER CONTENT / GUTLET SIZE) TO THE PITOT PROBES Which RESIST SHALL HAVE BEEN UPDATED WITH MORE Therefor Stringent REQUIREMENTS ON THE BASIS OF THE FIELD EXPERIENCE AND RECENT EXTENSIVE FLIGHT TESTING.
AIRBUS HAS LAUNCHED THE DEVELOPMENT OF THE modificiation followin:
1. DEVELOPMENT OF A NEW PITOT PROBE ABLE TO MATCH THE NEW REQUIREMENTS. ALL FLIGHT AND WIND TUNNEL TESTS TESTS ARE COMPLETED AND NOW SUCCESSFULL: THE CERTIFICATION OF A NEW PITOT PROBE HAS BEEN IN EARLY NOVEMBER Obtained 1996 (NEW PITOT PROBE: P / N 44836 851HL MOD). "(See document)
November 1996: The probe Rosemount P / N 0851GR is replaced by the probe Goodrich P / N 0851HL, (Service Bulletin A330-34-3038 for Model A330-301, -321, -322, -341, and -342 Series Airplanes) (ref. FAA states that this replacement is made necessary because the inconsistency of measured velocities can cause the A330 outside its flight envelope). This new probe is duly certified by Airbus.
December 1998: Emergence of the probe Sextant P / N C16195AA who replaces her as the probe Rosemount P / N 0851GR but for a limited number of A330 (Service Bulletin A330-34-3071 for Model A330-301 Series Airplanes) (ref.FAA). How the new probe has it been certified by the DGCA considering the experience Rosemount? For more demonstrates its inefficiency!
August 2001: The DGAC mandated these two replacements by AD 2001-354 (B) (see document):
"The following measures are rendered mandatory from the date of entry into force of this AD: Before December 31, 2003, unless already done, remove the pitot probe type ROSEMOUNT P / N 0851GR and replace them either by probes BF GOODRICH AEROSPACE type P / N 0851HL, according to the instructions of SB A330-34-3038, or by type probes SEXTANT P / N C16195AA accordance with instructions of SB A330-34-3071. "
July 2002: In the ILO 999.0068/02/VHR SE (see document), Airbus made the observation of defects of the probe Thales (formerly Sextant) P / N C16195AA
THE AIM OF THIS IS TO INFORM THE ILO OPERATORS THAT SEVERAL OPERATORS HAVE REPORTED SINGLE AISLE AIRSPEED ON AIRCRAFT FITTED WITH Discrepancy THALES PITOT PROBES PN C16195AA.
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Following is a series of conflicting decisions that demonstrate the inability of Airbus to get rid of one type of probe that meet standards dating from 1947, unsuited to the reality of the environment in which the aircraft ( see previous notes). The observation made for the probe Rosemount in 1996 has obviously not been used for the probe C16195AA!
September 2007: In a Service Bulletin (see document), Airbus recommends replacing the probe Thales P / N C16195AA by sondeThalès P / N C16195BA following further serious incidents.
September / October 2008: defects of the probe C16195BA Thales, "which was not designed to address the problems of icing, are recognized by Airbus and Air France (see the document Info TFN No. 5).
June 9, 2009: One week after the accident of Flight 447, the A330-F GZCP probe was equipped with Thales C16195-AA, Airbus launched an investigation into the case of inconsistency between the measured speeds reported by operators on Airbus A330/340 and took in early August decision to focus the probe Pitot Goodrich P / N 0851HL. EASA followed of course ...
One issue on which the DGCA must be answered is "How the Sextant pitot probe (later Thales) C16195-AA she was certified in 1998 given the experience Rosemount? "