Crash: Air France A332 over Atlantic on Jun 1st 2009, aircraft impacted ocean

[joeyb747]

Here is a very good article from Avherald about the crash of Air France 447. 

Maps and pics near the bottom...

http://avherald.com/h?article=41a81ef1/0051&opt=0

[Eric M]

Great article!

What is "alternate law?" As in:

"The airplane switched to Alternate Law at 02:10Z and remained in that law until end of flight."

[joeyb747]

All of the below info is from the article:

Following 25 ACARS Messages were received from the airplane:

2:10:10 -   .1/WRN/WN0906010210 221002006   AUTO FLT AP OFF
2:10:16 -    .1/WRN/WN0906010210 226201006   AUTO FLT REAC W/S DET FAULT
2:10:23 -    .1/WRN/WN0906010210 279100506   F/CTL ALTN LAW
2:10:29 -    .1/WRN/WN0906010210 228300206   FLAG ON CAPT PFD SPD LIMIT
2:10:34    #0210/+2.98-30.59
2:10:41 -    .1/WRN/WN0906010210 228301206   FLAG ON F/O PFD SPD LIMIT
2:10:47 -    .1/WRN/WN0906010210 223002506   AUTO FLT A/THR OFF
2:10:54 -    .1/WRN/WN0906010210 344300506   NAV TCAS FAULT
2:11:00 -    .1/WRN/WN0906010210 228300106   FLAG ON CAPT PFD FD
2:11:15 -    .1/WRN/WN0906010210 228301106   FLAG ON F/O PFD FD
2:11:21 -    .1/WRN/WN0906010210 272302006   F/CTL RUD TRV LIM FAULT
2:11:27 -    .1/WRN/WN0906010210 279045506   MAINTENANCE STATUS EFCS 2
2:11:42 -    .1/WRN/WN0906010210 279045006   MAINTENANCE STATUS EFCS 1
2:11:49 -    .1/FLR/FR0906010210 34111506   EFCS2 1,EFCS1,AFS,,,,,PROBE-PITOT 1X2 / 2X3 / 1X3 (9DA),HARD
2:11:55 -    .1/FLR/FR0906010210 27933406   EFCS1 X2,EFCS2X,,,,,,FCPC2 (2CE2) /WRG:ADIRU1 BUS ADR1-2 TO FCPC2,HARD
2:12:10 -    .1/WRN/WN0906010211 341200106   FLAG ON CAPT PFD FPV
2:12:16 -    .1/WRN/WN0906010211 341201106   FLAG ON F/O PFD FPV
2:12:51 -    .1/WRN/WN0906010212 341040006   NAV ADR DISAGREE
2:13:8 -    .1/FLR/FR0906010211 34220006   ISIS 1,,,,,,,ISIS(22FN-10FC) SPEED OR MACH FUNCTION,HARD
2:13:14 -    .1/FLR/FR0906010211 34123406   IR2 1,EFCS1X,IR1,IR3,,,,ADIRU2 (1FP2),HARD
2:13:45 -    .1/WRN/WN0906010213 279002506   F/CTL PRIM 1 FAULT
2:13:51 -    .1/WRN/WN0906010213 279004006   F/CTL SEC 1 FAULT
2:14:14 -    .1/WRN/WN0906010214 341036006   MAINTENANCE STATUS ADR 2
2:14:20 -    .1/FLR/FR0906010213 22833406   AFS 1,,,,,,,FMGEC1(1CA1),INTERMITTENT
2:14:26 -    .1/WRN/WN0906010214 213100206   ADVISORY CABIN VERTICAL SPEED

The cockpit effect messages mean:

- AUTO FLT AP OFF: The autopilot disconnected without crew intervention
- AUTO FLT REAC W/S DET FAULT: windshear detection is unavailable
- F/CTL ALTN LAW: FBW switched into alternate law (protections lost)
- FLAG ON CAPT PFD SPD LIM and FLAG ON F/O PFD SPD LIM: characteristic speeds (green dot, VLS, ...) lost due to loss of calculating function
- AUTO FLT A/THR OFF: Autothrottle disconnected other than by crew intervention or throttle levers were moved into the idle notch
- NAV TCAS FAULT: TCAS is inoperative, the message has not yet been explained
- FLAG ON CAPT PFD FD and FLAG ON F/O PFD FD: flight director bars have been removed from primary flight displays
- F/CTL RUD TRV LIM FAULT: The rudder limiter value computation is unavailable, the rudder remains limited to the present values until slat extension
- MAINTENANCE STATUS EFCS2 and MAINTENANCE STATUS EFCS1: not brought to the crew attention
- FLAG ON CAPT PFD FPV and FLAG ON F/O PFD FPV: flight path vector displays removed from the primary flight displays, red flags shown instead
- NAV ADR DISAGREE: Computers have rejected one ADR and then detected a disagreement between the remaining ADRs on one of the monitored paramenters.
- F/CTL PRIM 1 FAULT: Primary Flight Controls Computer 1 has stopped functioning either as result of a command or failure
- F/CTL SEC 1 FAULT: Secondary Flight Controls Computer 1 has stopped functioning either as result of a command or failure.
- MAINTENANCE STATUS ADR2: not brought to crew attention
- ADVISORY CABIN VERTICAL SPEED: cabin pressure changes at a rate of 1800 feet/minute or greater for 5 seconds.

Term   Explanation
Normal Law:   Regular operating mode of the fly by wire (FBW) including all protections.
Alternate Law:   Some of the protections in normal law, the regular operating mode, are dropped.
Direct Law:   The controls (sidestick) inputs are converted into direct movements of control surfaces without computations or checks.
ADIRU:   Air Data and Inertial Reference Unit provides air data (airspeed, altimeter, ...) and positional data (attitude, position) to the instruments
ISIS:   Integrated Standby Instrument System is a completely independent, self contained system providing a third independent set of basic instruments (attitude indicator, altimeter, airspeed indicator) to the crew
PRIM 1:   Flight Control primary computer #1, three of them monitor each other, one of them controls the control surfaces as master
SEC 1:   Flight Control secondary computer #1, each of the two can control all airplane control surfaces in direct law and can become master in case of failure of all primary flight control computers.

02:10Z:   Autothrust off
    Autopilot off
    FBW alternate law
    Rudder Travel Limiter Fault
    TCAS fault due to antenna fault
    Flight Envelope Computation warning
    All pitot static ports lost
02:11Z:   Failure of all three ADIRUs
    Failure of gyros of ISIS (attitude information lost)
02:12Z:   ADIRUs Air Data disagree
02:13Z:   Flight Management, Guidance and Envelope Computer fault
    PRIM 1 fault
    SEC 1 fault
02:14Z:   Cabin Pressure Controller fault (cabin vertical speed)

[joeyb747]

What is "alternate law?"

Check this page out. A direct comparison between NORMAL, ALTERNATE, ABNORMAL ALTERNATE, and DIRECT LAW is show here:

http://www.airbusdriver.net/airbus_fltlaws.htm

[laylow]

The BEA concludes from the damages, that the airplane was probably intact at the time of impact with the water, the airplane struck the water with a nose up attitude, low bank and a high rate of descent.

Autopsies were performed on 50 bodies, 45 passengers, 4 flight attendants and the captain. All injuries, mainly fractures of the spinal column, are compatible with a high upwards acceleration on a seated person. The autopsy of the captain does not allow a conclusion to the location of the captain at the time of impact.

That sounds like it went in top first, nose up, like they were upside down when they hit the water.  Is that how everyone else understands it?

[Biff]

An upwards acceleration means a downwards impact - as in seat first.

If it helps, translate that as a "downwards deceleration."

[laylow]

So belly first at a high rate of speed.  Thanks for clarifying.

[joeyb747]

So belly first at a high rate of speed.  Thanks for clarifying.

Yes, belly first, slight nose up attitude.

From the Avherald article:

"All damages were symmetric, no lateral forces became evident through the damages. All debris shows evidence of a high rate of descent at the time of impact with the water. The damages are not compatible with a separation of the aft part of the fuselage in flight. The left/right symmetry indicates, that the airplane had little bank/sideslip at impact. The damages are not consistent with a nose low attitude at time of impact.

The BEA concludes from the damages, that the airplane was probably intact at the time of impact with the water, the airplane struck the water with a nose up attitude, low bank and a high rate of descent."

[joeyb747]

The search for the black boxes continues...

"Today (Feb 4th 2011) the French BEA have disclosed details of the 4th search phase for the wreckage and black boxes of flight AF-447, which is going to start March 15th 2011 and last until July 2011 in three stages of 36 days (30 days search, 6 days transit for stop overs in Brazil) each. Three submarines (Remus 6000) are being used together with their exploration vessel "Alucia". This phase is dedicated to locate debris and the black boxes, uses small ships and is less expensive (9.3 Million Euros/12.5 Million US$) being funded by Airbus and Air France."

From:

http://www.avherald.com/h?article=41a81ef1/0053&opt=0

[iflyhi]

thanks joey  re: reply #2   good explanation of  "laws"  as i never fully understood it completly.

[alltheway]

The BEA concludes from the damages, that the airplane was probably intact at the time of impact with the water, the airplane struck the water with a nose up attitude, low bank and a high rate of descent.

Autopsies were performed on 50 bodies, 45 passengers, 4 flight attendants and the captain. All injuries, mainly fractures of the spinal column, are compatible with a high upwards acceleration on a seated person. The autopsy of the captain does not allow a conclusion to the location of the captain at the time of impact.

That sounds like it went in top first, nose up, like they were upside down when they hit the water.  Is that how everyone else understands it?

Nope it means that everyone who was not wearing a seatbelt was flying at the roof of the cabin (negative G forces) but those who were wearing them were like torture in the middle ages where people were pulled by 4 horses.
So the fractures of the spine is determined by that.
it was just a stall situation where the airplane went down in a level (slight right roll) situation as I understand it.....

[joeyb747]

...the airplane went down in a level (slight right roll) situation as I understand it.....

Pretty close, except...

"All injuries, mainly fractures of the spinal column, are compatible with a high upwards acceleration on a seated person."

"...the airplane struck the water with a nose up attitude, low bank and a high rate of descent."

From the AvHerald Article I linked to above...

[joeyb747]

thanks joey  re: reply #2   good explanation of  "laws"  as i never fully understood it completly.

Glad I could help! 

[jmx53]

Nova on PBS will be showing a program about this accident on FEB 16:

http://www.pbs.org/wgbh/nova/space/crash-flight-447.html

[aevins]

Nova on PBS will be showing a program about this accident on FEB 16:

http://www.pbs.org/wgbh/nova/space/crash-flight-447.html

It's currently available on NetFlix.

[glencar]

I watched it. It sounds like quite a few A330's & A340's had frozen pitot tube issues. I'm flying to Vienna next month & I hope it's a Boeing of some sort!

[CFD208]

Freezing pitot tubes in those weather conditions wouldn't be specific to an Airbus.  Or you could just be kidding and I just totally missed it.

[alltheway]

I watched it. It sounds like quite a few A330's & A340's had frozen pitot tube issues. I'm flying to Vienna next month & I hope it's a Boeing of some sort!

What is the difference of frozen pitot tubes in freezing conditions and
pitot tubes that freezes up due to heavy turbulence?

in this case frozen (ice) is different than freezes (stopped working due air fluctuations)

[joeyb747]

There was a known issue with pitot tubes on Airbus aircraft. It is not determined if the pitot tube failure caused this crash, but it is known that the airframe involved had not had the upgraded pitot tubes installed at the time of the crash.

"The Acars messages point to a discrepancy between three of the aircraft's speed data inputs of more than 30 knots within a period of less than a second. As a result, the system reported a fault and other subsystems - relying on the speed data - also triggered fault warnings, including the Air Data Inertial Reference Units.

Paul-Louis Arslanian, the head of the French air accident investigation office, BEA, says a pitot tube failure has not been confirmed, merely that the Acars messages point to speed sensors disagreeing with each other. However, he confirms that the aircraft had not yet undergone a pitot tube upgrade the airline had underway.

In a statement defending its actions, Air France says only since May of last year has it seen increased loss of air speed data associated with icing in the pitot probes on A330s and A340s and argues it has been instrumental in driving the upgrade program.

The airline says it upgraded pitot probes on A320 narrowbodies following Airbus's advice in September 2007 to do so; it didn't do so on the Airbus widebodies because at the time water ingestion did not appear to be a problem and no recommendation had been made to do so. Air France insists it asked for a fix once it started seeing anomalies on its A330s and A340s, but that Airbus at first said the A320 issue was different. The carrier says Airbus only let it be known that the A320 improvement could also benefit the A330 and A340. Once it heard that, Air France says it launched the A330, A340 pitot tube upgrade program on April 27 without waiting for a recommendation for Airbus.

The pitot tube upgrade Airbus developed is designed to improve measurement capability of the system."

From:

http://www.aviationweek.com/aw/generic/story_generic.jsp?channel=comm&id=news/AIRUP060809.xml&headline=AF447%20Did%20Not%20Have%20Pitot%20Tube%20Upgrade

See also:

http://www.aviationtoday.com/regions/weur/Airbus-Issues-Pitot-Tube-Warning_72053.html

[CFD208]

What is the difference of frozen pitot tubes in freezing conditions and
pitot tubes that freezes up due to heavy turbulence?

in this case frozen (ice) is different than freezes (stopped working due air fluctuations)

Maybe a pitot that stopped working due to air fluctuations may begin to work again.  Also, what are the odds that all 3 pitots simultaneously stop due to air fluctuations.  Whereas 3 identical pitots would theoretically freeze at the same rate and at the same time in icing conditions such as the super cooled liquid water that FLT447 may have encountered.
The symptoms of a failed pitot would be the same regardless of the reason for the failure. For example ice buildup or air fluctuations.

Just my $.02.  What does everyone else think?

[alltheway]

Also, what are the odds that all 3 pitots simultaneously stop due to air fluctuations.  

Weather was a classic ITZ scenario according to http://www.avherald.com/h?article=41a81ef1/0049&opt=0

http://www.businessdictionary.com/definition/intertropical-convergence-zone-ITZ.html

If it is to form rain, then I don't know if there are supercooled droplets involved, have to ask a weather expert for that....

[delta092b]

Nova on PBS will be showing a program about this accident on FEB 16:

http://www.pbs.org/wgbh/nova/space/crash-flight-447.html

It's currently available on NetFlix.

For any Canadian's wanting to try and get this on Netflix, don't waste your time. I just went through the process of signing up and it's not available outside the US. Sigh.