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 AF 447 FOUR WEATHER CELLS / June 1, 2009: 0:37 AM Data display derived from - BEA Report / Meteosat Meteorology Study |
| Target date to have our Air France, Flight 447 research completed is February 1, 2011. Photos and technical graphs are presented in a larger size than is usual for a web page so that details and small font text may be read as easily as is possible. This web page was coded for 1480 x 900 which is a wide screen (landscape) format. Printout will be 47 pages in 11 x 8.5 inch format. Please bookmark this page and occasionally check back to remain current with the publication schedule for the AF 447 Project. |
| Comments and opinions in this article are the sole responsibility of Bennett Blumenberg and do not reflect the views of any organization, government or private, that are mentioned in this article. The author does not have any relationship, public or private, with the organizations referenced in this article. Editorial and Proof Reading Services - Bruce Blake of Advanced Hybrid Aircraft. |
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ITCZ, CUMULONIMBUS and KILLER STORMS |
| The timeline narrative below for the last two hours of Air France Flight 447 is based upon: a) the 147 page BEA, Interim Report No.3 which was released on July 29, 2011 (French) and August 4, 2011 (English). BEA Report No.3 updates the narrative of Air France Flight 447 with significant new information because it is based upon the recovery of data from the Flight Data Recorder and Cockpit Voice Recorder. For those with a professional interest in the Air France Flight 447 tragedy, we recommend reading the entire 114 page report. "Crash: Air France A332 over Atlantic on June 1st 2009, aircraft entered high altitude stall and impacted ocean” by Simon Hradecky in the Aviation Herald is an excellent resource. 88 pages long, this article is also highly recommended for a complete read-through. Tim Vasquez's research into the weather encountered by Air France Flight 447 has no equal and is #3 of the "Big Three' references behind this web page. We hope that readers with more than a passing interest will also be enticed to read this page. |
 CUMULONIMBUS over the GULF OF GUINEA, 34,000' Photo posted by Neville at - Air France Flight 447: Comments from pilots and other aviation professionals at Tim Vasquez's site. |
 INTERTROPICAL CONVERGENCE ZONE Photo posted by Andy at - Air France Flight 447: Comments from pilots and other aviation professionals at Tim Vasquez's site. |
 DEVELOPMENT of CUMULONIMBUS CLOUDS JACDEC Special Accident Report - Air France Flight 447 |
 MULTICELLULAR THUNDERSTORM NATS: 101 Introduction Weather and Climate - Department Atmospheric Sciences, Univ.Arizona |
 THUNDERSTORM LIFECYCLE Private Pilot Ground School - Aviation Weather - Principles |
 DEEP CONVECTIVE SUPERCELL Data Display / May 20th 2010, Storm Chase - East Texas Skies / KLTV 7 Grant Dade Weather Blog, May 26, 2011 |
 TRMM's PRECIPITATION RADAR DATA OF HURRICANE BONNIE Hurricane.Bonnie-Towers in the Tempest - 'animation storyboard' - NASA.2007 by NASA/Goddard Space Flight Center Scientific Visualization Studio,, 2007 |
| Hurricane Bonnie came ashore on August 26, 1998 the North Carolina Coast, At that time, Bonnie was a Category 2/3 hurricane with top winds of 115 mph. The hurricane tracked towards the northeast and caused $USD 1 billion in the United States. Bonnie had degraded to a tropical storm off the coast of Newfoundland on August 29, 1998. Of particular interest to this research are the unusually tall cloud structures generated by this cyclone. Bonnie attracted more than casual interest at NASA and the Scientific Visualization Studio at the Goddard Space Flight Center assembled a team to script and produced an animation so these very tall dynamic cloud structures could be subjected to a fine grained study. While the weather data that has been released for the last ten minutes of Air France, Flight 447 does not allow for a straight forward reconstruction of the weather parameters of the flight envelope, there are features of the angle of attack and stall of F-GZCP that suggest the aircraft was briefly subjected to extremely strong, high energy updrafts. To that end, Chapters 3 and >>Link to exact section about Hurrican Bonnie in Chapter 4. --> 4 present several frames extracted from the animation movie about Hurricane Bonnie so that readers can better visualize the dynamic forces that may have been active and destructive to the aircraft. As is well known, the pitot-static system and other environmental sensors positioned on the exterior surface of the fuselage of F-GCZP were sending corrupt data - or none at all - to the computer systems. The responses then generated for the control surfaces were highly inappropriate. |
 HURRICANE BONNIE / UPDRAFTS and LOW LEVEL WINDS Hurricane.Bonnie-Towers in the Tempest - 'animation story board' - NASA.2007 by NASA/Goddard Space Flight Center Scientific Visualization Studio,, 2007 |
| This research is proposing that one very important specific set of parameters that the autopilot could not respond to properly were high energy, dynamic updrafts that reached unusual high altitude. Horizontal oriented wind velocity need not have been very high for this situation to be highly destructive to F-GZCP in less than one minute, and rainfall can be low as well. Note this quote and think on the situation that might have confronted F-GZCP at high altitude. "Low Precipitation (LP) Super cells usually form in dry regions, where there might be just enough moisture to form the storm, but not enough moisture to rain very hard. You can usually find the updraft on the rear flank (back) of the storm, and the meso will be more defined and obvious. On radar, an LP will not show up as a hook echo because there's not enough precipitation within the storm to provide the reflectivity. These storms might not look that strong, but they can pack a punch. LP super cells often produce tornadoes and large hail. |
 HURRICANE BONNIE / UPDRAFTS and HIGH LEVEL WINDS Hurricane.Bonnie-Towers in the Tempest - 'animation storyboard' - NASA.2007 by NASA/Goddard Space Flight Center Scientific Visualization Studio,, 2007 |
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 AF 447 - SINGLE HUGE WEATHER CELL / JUNE 1, 2009: 2:07 AM Data display derived from - BEA Report / Meteosat Meteorology Study |
 AF 447 THUNDERSTORM CLUSTER at IMPACT SITE / JUNE 1, 2009: 1:45 AM Satellite data - ©2009 Tim Vasquez |
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FLIGHT PATH, CRASH SITE |
| The date of the accident, that time at which all known activity associated with Flight 447 stopped, is given as June 1, 2009, 2h 14min 28s. The site of the accident, the coordinates at which Airbus A330 -203, Registration F-GZCP impacted the surface of the Atlantic Ocean (international waters), was 3°03’57’’ N, 30°33’42’’ W, near the TASIL point. The TASIL point is the location at which air traffic control switches from Brazil to Senegal. It is 2270 miles from Rio, but only 780 miles from Dakar, Senegal. There is a 390 mile wide dead zone from point INTOL to point TASIL within which there are no radio communications possible. Waypoint INTOL was reached 1 h 32 min 46 seconds after takeoff. |
 AF 447 Flight Path to Point TASIL Map - Brazilian Air Force |
| “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 on the INTOL – SALPU – ORARO - TASIL route at FL350. At around 2 h 02, the Captain left the cockpit. At around 2 h 08, the crew made a course change of about ten degrees to the left, probably to avoid echoes detected by the weather radar. At 2 h 10 min 05, likely following the obstruction of the Pitot probes in an ice crystal environment, the speed indications became erroneous and the automatic systems disconnected. The airplane’s flight path was not brought under control by the two copilots, who were rejoined shortly after by the Captain. The airplane went into a stall that lasted until the impact with the sea at 2 h 14 min 28.” (BEA 3rd Interim Report, p.7.) |
 Brightness Temperature (top) and False Color Images of AF 447 Impact Site Largest Mesoscale Convection System (MCS) indicated by colored circle - NASA Goddard Space Flight Center |
| Click Here to view a series of animations of the weather at and near the AF 447 crash site as prepared by the University of Wisconsin, Space Science and Engineering Center. Superb, do not pass over this link!. Back to Top |
WRECKAGE and DEBRIS FIELD |
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| Significant information will be gleaned from the analysis of aircraft components in the debris field. That work has begun and has provided details about the aircraft impact event with the ocean surface. |
| “The lower elements of the fuselage were badly broken up and deformed. In these areas, crushing of the sheet-metal between the ribbing was noted, which indicates a vertical component at the time of impact.” (BEA 3rd Interim Report, p.34.) |
| “The right half of the lower surface of the trimmable horizontal stabilizer, made of composite carbon fibre, had broken off on impact. The level of debris fragmentation and deformation indicated very high energy on contact with the surface of the water.” (BEA 3rd Interim Report, p.35.). |
| “The engine pylons were found separated from the wings. They had deformations compatible with stress on the engines from below to above.” (p. 36) “The APU exhaust broke off from the fuselage rear cone on impact. It had deformations on the whole of the lower section. (BEA 3rd Interim Report, p.37.). |
| “Both engines were visually examined. This examination showed that they were producing power at the time of impact.” (BEA 3rd Interim Report, p.39.). |
| “The trimmable horizontal, stabilizer screw jack was recovered on 5 May 2011 by the REMORA ROV. According to the manufacturer’s technical documentation, the relative position of the actuator and the THS screwjack corresponded to a THS position of between 13° and 13.5° nose-up.”(BEA 3rd Interim Report, p.39.) |
 AF-447 WRECKAGE on the OCEAN FLOOR as SEEN by REMORA Photographs - The Joe Lake Blog / Air France Flight |
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 AF-447 RETRIEVED AIRCRAFT COMPONENTS Retrieved wreckage of AF 447 - Brazil Air Force and Brazil Navy at Flightstory |
DATA RECORDERS |
| Recovery of the flight recorders, began on 22 April 2011. “The Flight Data Recorder (FDR) module was found and brought to the surface on 1 May and the Cockpit Voice Recorder (CVR) on 2 May 2011. The two recorders were taken to Cayenne from 7 to 11 May by a French Navy patrol ship. They were then transported to Paris by airplane and transferred to the BEA’s premises on the morning of 12 May. Work on the read-out began in the BEA’s premises on 13 May 2011 in the presence of accredited representatives from the CENIPA (Brazil), the NTSB (USA), the AAIB (United Kingdom) and the BFU (Germany) . . . . All 1,300 parameters from the FDR were available on 14 May and the read-out of the full 2 hours of CVR recordings was carried out on 15 May 2011. . . . The airplane parts were transferred to the French General Armament Directorate DGA) hangars in Toulouse for examination,” (BEA 3rd Interim Report, p.8.) |
Flight Data Recorder (FDR) –
Cockpit Voice Recorder (CVR) -
AIRSPEED / ADR and AUTOPILOT / LOSS of NORMAL LAW
AVIATION LAWS and FLIGHT DECK INSTRUMENTS
The LAST FIVE MINUTES
The STALL
“This modification of the behavior in the load factor at the centre of gravity results in the appearance of a high frequency component of an amplitude increasing to until about 0.1 g peak-to-peak, and with a signature that is very different from a turbulence signature of meteorological origin”. According to the simulation, the turbulence observed in the first seconds of climbing had stopped.(p. 43) “The airspeed displayed on the right-hand side may be partially deduced from the recording logic and from the fact that the associated angle of attack value from the ADR becomes invalid if the airspeed is less than 60 kt (the systems consider that the airspeed is insufficient for the angle of attack sensor to provide reliable information).”(BEA 3rd Interim Report, p.44).
SUPERCOOOLED WATER
RAPID DEGREDATION of SITUATIONAL AWARENESS
TIMELINE
Phase 1
FLIGHT 2H 10M 4S to 2h 10m 26s
Phase 2
ATTITUDE PROFILE
PITOT PROBLEMS / FIRST LOOK
STALL and ANGLE of ATTACK - FIRST CONSIDERATIONS
FLIGHT PARAMETERS FROM 2h 10m 26s to 2h 10m 50s
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FLIGHT PARAMETERS FROM 2H 10M 50S to 2H 11M 46S
The sixth chapter will look at 'hypercomplexity' as inherently problematic in aircraft design. The seventh and last chapter will attempt an integrative scenario - synthetic analysis - to explain the AF 447 tragedy. Several suggestions for changes to aircraft design and pilot training will be offered. Target date to have all chapters and appendices online is February 1, 2012, at which point this ebook can be read in a coordinated sequence. Photos and technical graphs are presented in a larger size than is usual so that details and small font text may be read as easily as is possible. The design of these web pages is optimized for a monitor
resolution of 1440 x 900. If your monitor is set to display smaller dimensions, horizontal scrolling of these web pages will be necessary. Please bookmark this page and occasionally check back to remain current with this publication schedule.
Items to Note: 1): “The value of the angle of attack is not directly displayed to the pilots. The angle of attack is the parameter that allows the stall warning to be triggered, but the activation threshold of this warning is indicated by a marker on the airspeed tape. When the ADR are rejected by the flight control computers, this marker disappears,” (BEA 3rd Interim Report: pp 20-21)
Flight Data Recorder Crash-Survivable Memory Unit(FDR CSMU)
Photo - BEA 3rd Interim Report
FLIGHT RECORDER MEMORY BOARD
Photo Flight Data Recorder memory board - BEA 3rd Interim Report“The memory board was cleaned. Visual inspection did not reveal any damage to the board. . . Analysis of the binary contents confirmed that the reader communicated correctly with the memory components and that the data extracted from each memory component was consistent.” (BEA 3rd Interim Report, p. 23) “Visual inspection of the boards revealed damage: a capacitor and a resistor were cracked on one of the boards; two decoder-type components were damaged on the other board. The boards were placed in an oven for 42 hours. The damaged components were unsoldered and replaced. The impedance value measured at the input connector complied with the measurements made on reference boards.” (BEA 3rd Interim Report, p. 24)
CVR MEMORY BOARD WITH THEREMAL PROTECTIONS REMOVED.
Photo - BEA 3rd Interim Report“The recorders were synchronized using the various alarms triggered during the flight, particularly the stall warning. The number of alarms made it possible to synchronize the recorders with an accuracy of approximately 100 ms." (BEA 3rd Interim Report, p. 25)
Back to Top“Analysis of the recorded normal load factor revealed zones of slight turbulence.” Note: According to the ICAO, “light” turbulence is defined as changes in the normal load factor at the centre of gravity of less than 0.5 g peak to peak. “The aural autopilot disconnection warning (cavalry charge) was heard at 2 h 10 min 04.6.”(BEA 3rd Interim Report, p. 26)
AIR DATA SELECTOR
Photo of Air Data Selector - BEA 3rd Interim Report“The airspeed displayed on the ISIS is also recorded by the FDR. This is comparable with the calibrated airspeed derived from ADR 3, since ADR 3 and the ISIS use the same external sensors (refer to interim report No. 1, section 1.6.6.1). It is always valid, even at airspeeds of less than 30 kt, as long as the dynamic pressure (total minus static) does not fall below a certain threshold. If this threshold is reached, the airspeed is invalid with a FW status (failure warning) and a message is sent to the CMC. The Mach from the ADR which provides information to the left-side PFD is also recorded. It is only displayed on the PFD when it is greater than 0.5.” . . . “Thus they show that the FD crossbars disappeared and reappeared several times during the flight.” (BEA 3rd Interim Report, p. 28) "Air Speed is THE critical data for the central computer system, and it is measured by pitot tubes by comparing the ram air pressure coming into the front of the tube with the static air pressure as measured by a static port on the side of the fuselage. The A330 has three independent pitot-static systems and it is very important they do not become blocked by dust, insects, ice, paint etc. One of the most important pre-flight checks is to check that the protective covers of the pitot-static sensors have been removed, and that they are not blocked. If the comparative check between air speed indicators during takeoff does not reveal proper function, then the pilot has the option to abort takeoff. “ When any flight deck crew notices a 'failure', there is a required Air France protocol for the processing of that anomaly. This procedure is believed by Air France to enhance as much as is possible: a) precise identification of the event; b) review of possible actions; c) implementation of most effective actions; and d) communication to all crew members and passengers. The necessity for “an immediate action performed from memory when the safety of the flight is directly compromised” is recognized. The entire protocol is explained on pp 54-55 of the August 4, 2011 BEA Interim Report No 3. In June 2004, Airbus published an “Unreliable Speed procedure (including a list of possible symptoms linked to erroneous speed or altitude information, among which [is recognized] the possible existence of undue stall warning.” The Airbus Procedure that has been in force since November 1997 (as described in the Airbus Flight Crew Operating Manual, Vol. 3) is reproduced on p.60 of the BEA Interim Report No 3. This protocol describes actions that were available to the pilots of Air France 447, Rio de Janeiro to Paris on May 31 to June 1, 2009, flying an Airbus 300 registration FGZCP. (This registration ID can be considered the 'name' of the aircraft and thus serves for precise identification of the plane that flew Flight 447. “ . . . conducted since the accident, and presented in the first two interim reports, it may be stated that the monitoring of the airspeeds by the FMGEC and the EFCS was triggered by the same variations in airspeed parameters, and thus at the same time, between 2 h 10 min 04 and 2 h 10 min 05 UTC. The two airspeeds recorded were still valid at this time; however, a false value point is present in the recording of the Mach. The low sampling frequency makes it impossible to determine the duration of the disturbance in the measured values; however, it is likely that it corresponds to when monitoring was triggered. This ADR rejection sequence will be specified in as much detail as possible, but in any case the triggering of the monitoring caused:
- the immediate disengagement of the auto-pilot (PA 2) and the transient
disappearance of the associated flight director;
- the loss of the normal law between 2 h 10 min 05 and 2 h 10 min 06. The position of the rudder limiter, set by the rudder travel limitation unit (RTLU) was stuck at 2 h 10 min 04.5 and the non-availability of the RTLU function was recorded between 2 h 10 min 17.5 and 2 h 10 min 18.5.
At 2 h 10 min 08, the two flight directors disappeared and auto-thrust was lost. This time interval was probably due to the fact that the three ADR were not rejected at the same time in the two FMGEC. The FMGEC which controls the active auto-pilot remembers any rejection.”(BEA 3rd Interim Report, p. 40)
ANGLE of ATTACK and FLIGHT PATH
Diagram - flight.safety.org
Back to TopClick Here for excellent graphs and animations about the weather that shaped the AF-447 flight envelope. Scroll slowly and read slowly.
Back to TopClick Here for excellent graphs and diagrams about Aviation Law, cockpit controls and data displays. Scroll slowly and read slowly.
Back to Top
. . . “the priority analysis work was selected to be on the two FMGEC, the two FCDC and the ISIS. . . . “At this stage in the investigation, it still has not been possible to perform the examinations.”(BEA 3rd Interim Report, p.32) Another simulation of aircraft behavior was run. It was based upon a theoretical model and the action of the PF with sidestick and thrust. The time period encompassed was 2 h 10 min 00 sec to 2 h 10 54 min. A headwind of 15 kt was added so that the simulation ground speed matched the ground speed data retrieved from the FDR. Before 2 h 10 min 40 sec, when FGZCB was climbing at 37,000', the recorded values for Angle of Attack, Normal Load Factor and Attitude fluctuated around the simulated parameters which revealed the presence of turbulence. After 2h 10 min 40 sec, the turbulence disappears and the simulated and recorded parameters are very consistent. “Consequently, it would appear at this stage in the work that the bulk of the aircraft movements in the longitudinal axis (attitude, vertical speed, altitude) result from the actions of the PF, with the exception of small variations that are probably due to the meteorological disturbances.”(BEA 3rd Interim Report, p.42)
Back to Top“At 2 h 10 min 51, when the aircraft was at about 37,500 ft and still climbing, the stall warning was activated (refer to 1.6.3). A change in the recorded normal acceleration behavior was revealed from 2 h 10 min 53, at an angle of attack about 1 to 2 degrees greater than the warning activation threshold.”(BEA 3rd Interim Report, p.43)
DIAGRAM of a STALL
Technical Illustration - autopica.wired-flightsafety.org The simulation also allowed for the recreation of the ECAM messages as they were displayed to the crew. Simulation work continues to: a) recalculate air speed from ADR 2; b) determine what instructions were displayed by flight directors' crossbars; and c) understand aircraft movement in three axes to further quantify the turbulence.
Back to Top“It should be noted that, at the time of the accident, the presence of ice crystals at high altitude was not considered to be an objective danger and that crews were not made aware of this.” (p.52) “A scale of 160 NM enables the change in the weather situation to be assessed and anticipate route changes. A scale of 80 NM is used for avoidance. Short scales must be periodically discontinued in order to observe distant weather conditions and to avoid an impasse amid the disturbances. The shape of the echoes may alert the crew to the possible presence of hail. Zones of turbulence may be presented above a detected zone of precipitation. Red or magenta zones as well as fringe-shape echoes must in this way be by-passed from windward by regularly adjusting the tilt and the range. The avoidance decision must be taken before the echoes are at 40 NM.” (BEA 3rd Interim Report, p.52). . . . “there may be strong turbulence 5,000 feet above the detected echo and that storms with peaks above 35,000 feet are dangerous.” (p. 54). “One Pilot's Personal Reflection” noted that turbulence within active cells of as strong storm can be strong enough to cause “structural failure”. He also observed that large hailstone almost always exist within such cells and can be “be thrown out of the top and sides of such storms, and it is best to avoid such cells by at least 20nms”. Granted that hailstones have not been confirmed in the storm that Air France 447 flew into.
SUPERCOOLED LIQUID WATE VERSUS TEMPERATURE
Graph - B. Geerts / University Wyoming “Supercooled [liquid] water (SLW) is common at normal altitude in and around thunderstorms, because in the absence of minute dust specks upon which ice crystals will form, water can remain liquid down to -40ºC. “ . . in young updrafts, or slowly rising layered clouds with cloud tops that are not too cold (above about -20ºC), SLW is often observed when such supercooled water touches anything, it will instantly turn to ice. If GZCP flew into super cooled water, the leading edges of the airframe become immediately covered with ice reducing lift and enhancing drag of the airfoil. Engines and pitot tubes are also severely affected very quickly.”
Back to TopOn board weather radar systems have limitations in the detection of turbulence within developing weather systems. These limitations should be mentioned because the size and strength of the turbulence encountered by Air France 447 with the ITCZ is important and still a subject of some controversy. One of the best insights into
these limitations is provided by the Accident Report by the Hong Kong Transportation Safety Board (HTSB); about Dragon Airlines, Flight KA-609 from Kota Kinabalu, Malaysia to Hong Kong which flew an Airbus A330-300, registration B-HYA.
DRAGONAIR AIRBUS 330 - 25th ANNIVERSARY LIVERY B-HYF - 港龙航空廿五周年金龙彩绘空客330
Photo at Flikr by - Dennis Wu 14 crew and 216 passengers encountered severe turbulence while in cruise at FL 410 and deviating from the airway due to information provided by the airborne weather radar system. When this incident had ended, all 12 cabin crew and 3 passengers were injured. Flight KA-609 had accidentally flown into a zone of severe turbulence that was created by strong convective activity associated with a tropical depression. Review of the cabin Flight Displays revealed that the crew was not able to view the developing weather pattern accurately,and therefore could not understand the severity of the developing weather. When a deviation from the flight plan and flyway was finally initiated, it was not sufficient to avoid the severe turbulence. To quote paragraph 2.2.2 from the HTSB Accident Report:
“Weather radar detects droplets of precipitation. The strength of the return depends on the size, composition and amount of droplets. Water particles are almost five times more radar reflective than ice particles of the same size. Weather radar is therefore effective in detecting rainfall and wet hail but not effective in detecting the upper level of a storm cell where most moisture exists in a dry, frozen state, i.e. in the forms of snow, ice crystals and hail. To determine the positions of storm cells, the antenna tilt angle should be adjusted to scan the icing level, where reflective water-covered ice/hail would be abundant. Above the icing level, ice crystals have minimal radar reflectivity. Although convective activities and turbulence exist at these levels, they do not show up readily on radar. To keep track of weather in the vicinity of the flight path, the antenna tilt angle should be frequently adjusted to scan the most reflective area in the icing level band. As altitude changes or as the aircraft gets closer to the storm cell, the tilt angle has to be changed so that the radar beam keeps scanning the most radar reflective area.” One result of working with a deficient portrayal of rapidly developing severe weather is that crew responses cannot be optimized. American Airlines, Flight 587 crashed shortly after takeoff from Kennedy Airport (NYC) on November 12, 2001. The United States NTSB Report about this incident revealed that unnecessary and excessive rudder pedal inputs caused the tail and fin to detach from the fuselage and cause the crash. Frequent and unnecessary rudder pedal inputs were also a feature of the PF response and near arguments between crew members in the cockpit of Air France Flight 447 as CVR data revealed. However, there are important differences to keep in mind. With AA Flight 587 in 2001, “the entire rudder separated from the vertical stabilizer except for portions of the rudder spar structure that remained attached to hinge arm assembly numbers . . . “ The crash of American Airlines, Flight 587 is discussed in detail in Chapter Five (5). As regards Air France, Flight 447, the rudder remained attached to the vertical stabilizer (fin).
AF 587 / VERTICAL STABILIZER SALVAGED FROM JAMES BAY, NEW YORK
Photo - AA 587 Accident Report, NTSB
Back to TopVia radio or satellite, the Aircraft Communications Addressing and Reporting System (ACARS) transmits short, technical messages about the state of the aircraft. This message base is intended to outline a maintenance protocol protocol that should be attended to asap after landing. In a crisis situation where many of the usual communications from the cockpit are not possible, ACARS provides an invaluable record of problems with essential aircraft functions. At the beginning of the CVR recording, just after midnight, the airplane was in cruise at flight level 350. Autopilot 2 and autothrust were engaged. The automatic fuel transfer to the “trim tank” was carried out during climb, and the airplane’s balance 27.5%, for a weight of 218 tonnes. The flight was calm. The crew, made up of the Captain and a copilot, was in VHF contact with the Recife control centre. . . They were concerned about the closing of one of the ETOPS alternate airfields, Sal-Amilcar in Heading Verde. They asked the OCC for a change who answered that the airfield was open in case of emergency. . .. At around 1 h 35, the airplane arrived at the INTOL point and the crew left the Recife frequency to pass over to HF communication with the Atlantic oceanic control centre. A SELCAL test was carried out successfully, but the attempts to make the ADS connection with Dakar Oceanic failed. Just afterward, the copilot modified the scale of his ND from 320 NM to160 NM and noted that “there’s something straight ahead”, which was doubtless a reference to some direct radar echoes detected by the weather radar. The Captain confirmed and the crew again discussed the fact that the high temperature meant that they were not’t able to climb to FL370.
AF 447, FLIGHT PLAN WAYPOINTS
Data table - BEA 3rd Interim Report re Air France 447AT 1h 45, the airplane entered a slightly turbulent area, just before the SALPU point. Note: at around 0 h 30 the crew had received some information from the OCC on the presence of a convective zone linked to the ITCZ between SALPU and TASIL. The crew dimmed the cockpit lighting and turned on the lights “to see outside”. The copilot noted that they were going to “go into the layer” and that it would have been good to be able to climb. A few minutes later, the turbulence became a little stronger and the copilot proposed requesting a climb to level 360 non standard because he thought he was “really at the edge” of the cloud layer. The Captain answered that they would wait a little. He reduced the scale on his ND to 40 NM; the weather radar then changed to weather + turbulence mode. A little later he mentioned the appearance of Saint-Elmo’s fire and said that “it’s going to be turbulent” when he went to take a rest. A little after 1h 52, the turbulence stopped. The copilot drew the Captain’s attention to the value of REC MAX, which then reached FL 375. The Captain made no comment.
AF 447 PROJECTED FLIGHT PATH BLENDED WITH SATELLITE WEATHER DATA
Photos, Data Schematics - PPRuNe and Weather Graphics (Tim Vasquez)At 1h 55, the captain left his seat to take a rest without leaving instructions or assigning tasks for the two First Officers. The BEA believes that because of the captain's lack of guidance, there was an absence of formal framework and a breakdown of communication between the two First Officers. This charge is serious and the basis for criticisms of pilot communication, non-optimal task-sharing and subsequent flying decisions. Likely, the captain did not know what do beyond what he said. Greater experience aside, the captain had not received any specific training that would have prepared him for this situation. It was also possible, that each crew member was beginning to sense that the cockpit displays were not an accurate representation of the weather situation and its rapidly changing interaction with the flight envelope.
FLIGHT ENVELOPE AERODYNAMICS/font>
Chart - Airplane Upset RecoveryThe second first office took the captain's seat. The First 1st Officer in the right hand seat became the Pilot Flying (PF), and the Second 1st Officer in the left seat was now the Pilot Monitoring (PNF). The First 1st Officer (PN) then pointed out to the PNF that “the little bit of turbulence that you just saw […] we should find the same ahead […] we’re in the cloud layer unfortunately we can’t climb much for the moment because the temperature is falling more slowly than forecast”. . . . . . . The copilot in the right seat said that they were “apparently on the edge of the layer”, before adding that he would have preferred to climb to FL 360. Climbing to a higher level was a preoccupation for the crew. The pilots clearly wanted to fly outside of the cloud layer, probably to limit turbulence. The conversations in the cockpit did not reveal any malfunction of the weather radar nor worries that the display might not be a usable image. The background noise changed rapidly at ~ 2 h 09 min 46 and was identified as possibly indicating ice crystals but the crew did not comment. The weather phenomenon now surrounding FGZCP were of a type little known to pilots at the time. The PNF then took the initiative to reduce the Mach towards 0.8 and the engine anti-ice devices were triggered. The PNF appears to act with confidence and demonstrated an ability to make decisions that accommodate to a rapidly changing situation. Unfortunately, because it was not possible to quickly understand the degradation of the PFD, decisions made were doomed to be less than optimal.
Back to Top
Flight Parameters at 2h 10m 04s to 2h 10m 26s
Chart- BEA 3rd Interim Report Air France Flight 447Click Here to view this graph in a vertical orientation which makes reading before 2h 11h 55sec easier. Click the + magnifier, then CTL ++ to enlarge the image further. Scroll slowly and read carefully.
Back to TopAt 2 h 10 min 05, the sudden drop in the measured airspeeds, likely due to the obstruction of the Pitot probes by ice crystals, caused autopilot and autothrust disconnection (the thrust was then locked) and the change in flight control from Normal Law to Alternate Law. Airspeed decreased from ~275 knots to 60 knots, indicated air speed was displayed in the left side PFD. Significant turbulence is revealed by Autopilots inputs and the aircraft rolled about 8 to the right. The nose pitched up to 11º within ten seconds. “The PF announced "I have control" and made a quick left nose up input almost to the mechanical stops of the side stick. The nose pitched further up and at 02:10:10Z the stall warning activates.” The Flight Directors were not disengaged by the crew, but the crossbars disappeared.
AF 447 FLIGHT TURBULENCE EPISODES DURING FLIGHT
Data table - BEA 3rd Interim Report re Air France 447
Back to TopClick Here to view this graph in a vertical orientation which makes reading before 2h 11h 55sec easier. Click the + magnifier, then CTL ++ to enlarge the image further. Scroll slowly and read carefully. Click Here to view a large, detailed AF 447 / SCHEMATIC ATTITUDE PROFILE, 2h 08min 07sec to 2h 14min 27 sec at which time the last ACARS message noted extreme vertical speed at a altitude of less than 4,000'. Click the + magnifier to display the graph at maximum size, then scroll slowly and read carefully. This graph is a superb data presentation, please do not pass over this link.
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Back to TopAuthor's note: It is impossible not to notice that the pitot tube system receives only very brief mention in the BEA 3rd Report. “One Pilot's Personal Reflection” elaborates. “The pitot tube captures ram air, which is sensed by an Air Data Module in the A330, and converted to airspeed. The drain tube allows water to pass without clogging the pitot. To do that, it passes air all the time. The pitot opening is a specific size, say 5mm diameter, and the drain is maybe 2mm. That makes the pitot about 20 sq. mm area, and the drain about 3 sq. mm area, for a ratio of about 7:1. This means the ram air pressure at the sensor is about 14% less than actual ram air pressure.” “When it comes to clogging at high altitude, there are three possibilities:- 1. Pitot clogged, drain clogged at same time:- Indicated Air Speed (IAS) will not change with change of aircraft speed, but IAS will increase with increase of altitude. 2. Pitot open, drain clogged:- IAS will increase 14%. 14% excess IAS will remain regardless of actual airspeed or altitude. 3. Pitot clogged, drain open:- IAS will decrease toward zero as the drain bleeds off the ram air pressure to ambient. Increased altitude will not affect IAS.”
Back to Top“Stalling occurs when the wing reaches an Angle of Attack (AoA), the angle at which the air hits the leading edge of the wing, when the airflow over the top of the wing breaks down completely and becomes turbulent. When the break point is reached, lift is lost until the AoA is reduced to a point where normal airflow over the wing is re-established. During certification test flying. a lot of very brave flying is done to ensure that the aircraft exhibits sufficient warning (increasing airframe buffet) before the break point, and that at the break point the aircraft pitches nose down so that it re-establishes a normal AoA. . . . “Stalling occurs when the Angle of Attack (AoA) exceeds the critical point, usually around 15 degrees nose up. Once the AoA goes beyond this point the air flow separates, causing buffeting and loss of lift. . . . The only way to uninstall the wing is to pitch the nose down so as to reduce the AoA to less than 15 degrees However, the critical AoA at higher Mach numbers can be considerably less than this and there are several problems that pilots do not always adequately understand. The first is the deep stall which can happen on T-tailed aircraft . . The deep stall occurs when the turbulent air flow from the wings blanks the elevators such that they lose all effectiveness.” When autopilot and auto-thrust were no longer available and the aircraft reverted to Alternate Law - “Hello PF, FGZCP systems needs your direct input from this point forward!”, the pilots had to fly the aircraft using power and attitude table data displays IF those were available.
AF 447 SEVERE WEATHER WATER VAPOR, WIND SHEAR
Animation- University of Wisconsin / Space Science Engineering Center / CIMSS Blog
“The only way to uninstall the wing is to pitch the nose down so as to reduce the AoA to less than 15 degrees
However, the critical AoA at higher Mach numbers can be considerably less than this. But there are several problems that pilots do not always adequately understand. The first is the deep stall which can happen on T-tailed aircraft . . The deep stall occurs when the turbulent air flow from the wings blanks the elevators such that they lose all effectiveness.”
At 2 h 10 min 10, the PF’s nose-up inputs increased the angle of attack and the stall warning triggered twice transitory. Probably in reaction to this warning, the PNF exclaimed “what is that?”. The PF then said “We haven’t got good … We haven’t got a good display … of speed” and the PNF says “We’ve lost the speeds” which the first clear indication on the CVR that the crew recognizes serious trouble has arrived. The angle of attack recorded was around 5°, for a theoretical stall warning threshold trigger value of slightly over 4°.
At 2:10 min 16, a cockpit display informs that an ACARS message AUTO FLT REAC W/S DET FAULT was sent because wind shear detection had become unavailable.
ISIS DISPLAY on the PFD
CGI - PPRuNe blog
Between 02:10:18 and 02:10:25 the PNF reads various ECAM messages in a disordered manner, noted the loss of speed (autothrust) and change-over to Alternate Law to the PF. Both left hand and ISIS air speeds were now below 100 knots, AoA had increased to more than 10º. (The Integrated Standby Instrument System (ISIS) is a backup, independent source data for attitude, airspeed, Mach, altitude and vertical speed.) The aircraft was climbing 700 feet/min and then rolled left and right. The bank angle remained between -10 (left) and +13 (right) degrees of bank, as result of PF inputs. The thrust lock function was de-activated. Both first officers recognized the loss of airspeed indications, however none called for the unreliable airspeed procedures. Comparing the three airspeed indications the PNF urges the PF several times to lower the nose and descend. The aircraft was climbing through FL370 and continued to climb.
Between 2:12:27 and 2:12:33, the CVR records the confusion of the PF that the aircraft was climbing when it should be descending. Click Here to view a large, detailed AF 447 / SCHEMATIC ATTITUDE PROFILE, 2h 08min 07sec to 2h 14min 27 sec at which time the last ACARS message noted extreme vertical speed at a altitude of less than 4,000'. Click the + magnifier to display the graph at maximum size, then scroll slowly and read carefully.
Back to TopClick here for a video of the meteorological conditions in the Inter tropical Tropical Convergence Zone as seen by Meteosat (Infrared, from 30th May 0h UTC to 4th June 0h UTC). (Video is in .avi format.)
ECAM MESSAGES at DIFFERENT TIMES
ECAM Messages- BEA 3rd Report, Air France Flight 447The crew identified the loss of the speed displays but neither of the two copilots called out the associated procedure. The “Unreliable IAS” emergency maneuver requires as a first step to disconnect the automatic flight controls and disengage the Flight Directors. The two copilots had only been trained for the emergency maneuver at lower levels, in the course of which the pitch attitude to adopt is 10° or 15°. However, an OSV note described the problems of the loss of speed indications up to then on the A330/A340 fleet in cruise and recalled the procedures to apply. This note had been distributed to all the flight crew in the A330/A340 division.
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FLIGHT PARAMETERS at 2H 10M 26S to 2H 10M 50S
Chart- BEA 3rd Interim Report Air France Flight 447 The latter then made several nose-down inputs that resulted in a reduction in the pitch attitude and the vertical speed, whose values nevertheless still remained excessive; the airplane then being near 37,000 ft and continuing to climb, without any intervention from the PNF. Although the REC MAX had been a permanent preoccupation before the AP disconnection, neither of the two copilots made any reference to it. At around 2 h 10 min 34, the speed displayed on the left side rose rapidly to 215kt and became valid again; the speed on the ISIS was still incorrect. FGZCP had lost ~60 kt since the autopilot disconnection and the beginning of the climb, which is consistent with the increase in altitude of ~2,000 ft. At 12:10:45, there is a slight argument between the PNF and PF about putting the wings level. At 2 h 10 min 47, the thrust levers were slightly retarded to 2/3 of the IDLE/CLB (85% of N1) range. Two seconds later, the pitch attitude went down a little to 6°, the roll was controlled, the angle of attack was slightly below 5° and the THS was 3° nose-up. The vertical speed was reduced from a high at +1,100 ft/min to 100 ft/min .The angle of attack was reduced to ~3 degrees and the roll was controlled and the flight of FGCP likely appeared 'normal' at this time. In the following seconds, the PNF tried to call back the Captain During this phase, at no time did either of the two copilots make any callouts on speed, pitch attitude, vertical speed or altitude. The Flight Directors not having been disengaged, the cross bars disappeared and reappeared several times. It is not possible at this stage pf the investigation to know what orders may have been given, nor to establish if these orders influenced the actions of the PF. After a rapid increase in pitch attitude and altitude, resulting from the PF’s inputs, the airplane’s flight path seemed to have been mastered. The increase in initial pitch attitude and magnitude of vertical speed were excessive for this flight altitude and should have led to immediate call outs of the discrepancies by the PNF. The absence of specific training in manual aircraft handling at high altitude likely contributed to the inappropriate piloting inputs and surveillance. The low level of synergy observed between the two copilots may have resulted from the absence of a clear attribution of roles by the Captain, as well as from the absence of any CRM training between two copilots, in a situation with a relief Captain. However, there are no regulations that require such training nor guidelines for taking decisions when designating the relief Captain during flights made by reinforced crews. All commentators agree that the each crew member was very experienced for their specific assignment in the crew of FGZCP, Air France Flight 447. Intuition, however irrational and unprofessional, intuition should not be dismissed as irrelevant in a situation such as this. Each pilot brings their previous flying experience to each flight, and intuition is automatically in play when there is no immediate explanation for a situation. Because intuition is not rational, is not a linear deductive process, hesitation in revealing intuitive thoughts to colleagues and a superior is understandable. Pilots are human beings and a deep technical training does not eliminate, the irrational components of the human mind. Furthermore, everyone can recall situations where an intuitive assessment proved accurate and valuable.
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FLIGHT PARAMETERS FROM 2H 10M 50S to 2H 11M 46S
Chart- BEA 3rd Interim Report Air France Flight 447
Click Here for professional data displays about the Angle of Attack, the devastating stall, and the last minutes of AF Flight 447.
This web page is an appendix from the eBook that derives from our Air France Flight 447 project. Chapters and appendices from this ebook are released out of sequence so as to make them available at the earliest possible date.
The first chapter in the Air France, Flight 447 eBook introduces the flight of Airbus F-GCZP from Rio de Janeiro to Paris, May 31/June 1, 2009 and the serious problems that soon became apparent to the crew. The second chapter in this eBook discusses the search for the wreckage of Air France, Flight 447, and the recovery of the Flight Deck Recorder and Cockpit Voice Recorder. The third chapter reviews the last five minutes of Air France, Flight 447. The fourth chapter examines the design and function of the pitot-static and angle of attack sensors whose data is essential to the Fly-By-Wire computer system interaction with flight control surfaces. There is a consensus that iced over pitot tubes rendered the Airbus 330 computer system unable to properly instruct flight control surfaces because the data stream the conveyed essential parameters about the flight envelope was either absent or corrupted from a critical time point forward. The fifth chapter will look at the vertical stabilizer of Airbus 330 aircraft, review the problems inherent with carbon-resin components in aircraft design, review aviation incidents in which tail components detached from the aircraft fuselage, and attempt to assess the contribution to the Air France FLight 447 tragedy that was made by the loss of the vertical stabilizer.
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