Pax and Crew File Lawsuit Against Airbus

[teresa green]

Capt SNAFU, they had war nerves, they had mental problems, they were angry, they resented that they had lost their youth in war, but I never saw one show fear. Their attitude was that they survived and anything a airliner could throw at them was a piece of cake. I was totally in awe of them, and one, the late Capt. Gordon Close was the best pilot I have ever seen. Nothing, but nothing fazed this bloke, and I well remember going into OOL on a black and stormy night, the aircraft all over the sky, and as you know not much in the way of aids, and Im thinking we are not going to get in here, and there is Gordon, a scratch and a yawn and sets her down like a cat pissing on glass, smooth as, never seen anything like it, and that was typical of these blokes, no sweat, was their attitude, probably would be considered too casual these days, they were tough buggers, but could they fly.

[swh]

Originally Posted by Capn Bloggs

So Wiki was right.

On the 777 in the normal Primary Flight Computers (PFC) mode (AUTO) the control column inputs are process by the Actuator Control Electronics (ACE), sends them to the PFC via the ARINC 629 data busses, the PFC gets inputs from other inputs like the ARIDU via the ARINC 629 data busses as well. When the PFC are in the AUTO position, the PFC supply the actuator position commands to the ACE, which in turn converts them into an analog servo command moving the control surfaces.

The PFC in pitch mode is a manoeuvre demand control law, at low speed pitch rate is the controlling factor, when the aircraft was in the low speed regime as the pilots push or pull of the control column, the PFC then converts that into a desired change of pitch rate of the aircraft, and then generates the desired flight control commands to acheive that pitch rate. As the PFC thought it went into the high speed regime, as the pilot moved the control column was interoperated by the PFC to change the given load factor, the PFC then converts that into a desired change of load factor of the aircraft, and then generates the desired flight control commands to acheive that load factor. This is why the pilot somewhat over controlled the recovery.

The manoeuvre demand control law on the 777 places significant reliance of the accelerometer values supplied by the ADIRU, as it is so significant, a secondary source the Secondary Attitude Air Data Reference Unit (SAARU) is also used by the PFC to try and eliminate any possible input errors. The commanded flight control outputs on 9M-MRG would have been a lot worse if the PFC did not compare mean values of the ADIRUs and the SAARU.

During manual flight the aircraft continued to pitch up and enter the low speed protection (while the pilot was commanding nose down via the control column), stick shaker activated, overspeed protection was also activated. This was due to due to accelerometer #5 providing false information to the PFC.

Basically all of the "misbehaviour" happened AFTER the A/P was disconnected at the 46 sec point in the animation. The accelerometer that failed at the time of the event (#6) actually got voted out at the time of the event, but a long time faulty accelerometer (#5) was voted in.

The ATSB included on the last page of their report a copy of the screen capture, in that you can clearly see the A/P disconnected, throttle commanded via the T/L to zero, commanded nose down pitch on the control column, and the aircraft continuing to pitch up. This is due to the PFC combining the various inputs to what it sees as being the desired output.

The pilot pressed the throttle lever A/T disconnect switches continuously for a period of approximately 90 seconds, during that time the A/T was not engaged in any mode, with the release of the A/T disconnect switches the low speed protection placed the A/T engaged the A/T speed mode.

On the 777 the ADIRU accelerometer values are processed by the Fault Containment Area (FCA)/Fault Containment Module (FCM) and sent to the to the PFC over the ARINC 629 data busses which produces navigation and flight control output in both manual and automatic flight to the FCS. Disconnecting the A/P does not remove the accelerometer inputs to the FCA/FCM, nor from the PFC. Acceleration values are needed by the PFC in all flight regimes, autopilot engaged or not.

The ATSB coved this on page 9 of their report “Even though the second fault resulted in proper annunciation of a status message, the ADIRU flight control FDI algorithm which excluded accelerometer number -6 from the flight control outputs at the moment it failed, erroneously allowed accelerometer number -5 back into the computation of the flight control outputs.”

To remove all influence of faulty acceleration values on the FCS would require the pilots to move the PFC switch on the overhead panel to the DISC position, that is the only way to remove the PFC from the FCS and put the FCS into direct mode. In direct mode, the ACEs do not process commands from the PFCs. Instead, each ACE decodes pilot commands directly from the transducers on the cockpit controls and uses them for the closed loop servo control of the actuators (direct law). This mode will automatically be entered due to total failure of all three PFCs, failures internal to the ACEs, loss of the flight controls ARINC 629 data busses, or some combination of these failures. It may also be selected manually via the PFC DISC switch on the overhead panel.

That was not done by the crew, nor did the ATSB consider it.

The main reason for the different outcomes from the two events was that 9M-MRG only occurred 18 minutes after departure. It actually experienced much higher accelerations, rates of climb/descent, and pitch range over the A330 event. If this happened several hours into the flight after a meal service with many people waiting to use the toilet, I think the outcome would have been very different.

Originally Posted by CONF iture

The 777 upset was AP and AT induced.

No, it was caused by erroneous acceleration values, it was not induced by the A/T or A/P.

The ADIRUs were pulled from the aircraft, and tested by the manufacturer, it was determined that the ADIRU’s accelerometer #6 failed at the time of the occurrence, and that accelerometer #5 failed in June 2001 (4 years earlier).

Originally Posted by CONF iture

The 330 was nicely manually flown when the protections did the mess.

The AoA sees the relative airflow direction at the position of the vane, it changes with attitude, airspeed, configuration, sideslip etc.

It is apparent from the FDR data plots that a pilot did contribute pitch commands to the FCS at the time of the two events. The ATSB has not stated that pilot inputs did or did not influence the outcome.

The ATSB have not published their investigation findings which one would hope would make this consideration. Nor has the ATSB considered the other crew actions that were and were not completed.

It is also apparent that over 30 AoA spikes were recorded in the FDR (which was limited by the sampling rate), however 3 nose down pitch events were seen. If it was as simple as you were suggesting that it was the protections kicked in, one would assume that a correlation would then exist between all the AoA spikes and the pitch events.

The ADIRUs were pulled from the aircraft, and tested by the manufacturer under ATSB supervision, no fault was found with them, this is very different to 9M-MRG where component faults (accelerometer) were found.

That is why the ATSB has stated it is looking into the possibility of cosmic radiation as being the possible cause, it might conceivably cause a problem inside the volatile memory in the ADIRU, or even in the analogue to digital converter for the AoA probe.

A fault message in modern avionics equipment does not necessarily mean an internal problem within that unit, it can also point to a problem with an input used by that equipment failing to pass the continuous fault tolerant testing they perform. The ADIRUs not only monitor faults within the ADR and IR, they also monitor the performance of the probes/vanes and the probe heat computers.

[adsyj]

Guys (and girls) I am a bit of a fence sitter on this one.

I agree with TG and I also agree with Keg (including his praise of the contribution TG makes to this forum.)

My understanding, and I am happy to be corrected is that the Tech Crew did not instigate the legal action rather they were invited to join the class action. I am told that if this indeed ends in court the flight crew regardless of whether they are part of the class action will be in the witness box for the applicants and will therefore be cross examined by the defense team. This could be an unpleasant time with the defense team throwing all sorts of pressure on the flight crew. Again my understanding is the actions of the crew was perfect but a smartarse defense lawyer can make your time in the witness box particularly unpleasant.

My thoughts are if they are going to be called why not join the class action, if they are all in.(Flight Crew) Possibly cop a hammering by the defense which would happen anyway (called as witnesses) the difference being instead of being subpoenaed witnesses they might be in for a bit of a "drink" if it goes the applicants way. Why not?.

They are not suing there employer but the Aircraft Builder and a specific part supplier.

In saying all that if it were me on duty that day, would i sue? I honestly don't know.

I would hope that the thought would not even cross my mind and be satisfied that I went to work and did my job, but I honestly can't say that would be my answer.

I hope that this is not misconstrued as criticism of the flight crew (definitely not my intention)

It is just food for thought and a different angle to consider before we hang the crew.

As I said earlier I agree sort of with Terese Green but I also agree with keg and others. I hope it is a conundrum I never have to face.

Either way my colleagues will have my support whichever way it turns out.

Happy to be corrected if any of my assumptions above are wrong.

[unseen]

blah blah blah

blah blah blah

I don't really know anything about the facts but I will comment on it anyway,

blah blah blah

I read something in the papers so I am an expert and will bang on about how others should deal with things that I have no knowledge of

blah blah blah

probably knowing nothing about anything to do with this event I will comment and make references to all sorts of crap that has nothing to do with this situation.

blah blah blah

[C441]

Capt SNAFU, they had war nerves, they had mental problems, they were angry, they resented that they had lost their youth in war, but I never saw one show fear.

Forgive the thread drift but this reminded me of the quote from Keith Miller, a WWII fighter pilot, brilliant all-rounder on the cricket ground, and ex St Kilda footballer.

After a particularly Miller-like innings in difficult conditions he was asked if he'd felt any pressure during his innings.

"Pressure, I'll tell you what pressure is,'' he said. "Pressure is a Messerschmitt up your arse, playing cricket is not,''

[CONF iture]

Thanks for the reply swh, interesting reading.
Obviously, you seem to have a good technical knowledge of the 777, which I don’t, but still, I have to stand to my earlier post.

The 777 initially pitched up under AP which was following the FD commands. AP disconnect came up only at time 17:03:16 Airplane was already 10 degrees NU.
Then the manual FWD displacement of the control column didn’t seem aggressive enough to stop the pitch up movement. The guy seems undecided : Do I follow the FD or I do it my own way ?
Another point is : How was the trim at that moment ? I haven’t seen that piece of information …

As stated by Boeing, you are correct to say that not only the AP was affected by the erroneous accelerations, but also the manual flying.

Erroneous accelerations will affect the Primary Flight Computer (PFC) control laws during manual and automatic flight

But it is also said :

The flight crew should disconnect the autopilot and manually fly the airplane. Although initial manual control forces may be high, the affects of the ADIRU anomaly on manual control forces are expected to diminish within 10 seconds and should be back to near nominal within 2 minutes.

The flight crew should also disconnect and disarm the autothrottle via the arm switches on the MCP if there is any undesired behavior.

I find this idea of direct mode switch interesting, Airbus should have a serious look to it.

Questions :

1. Is it a single DISC switch for all 3 PFCs or one switch per FPC ?
2. Except from an automatic transfer, is there an ECAM or QRH procedure to command to switch to direct mode, or is it something left to the pilots judgment ?

The main reason for the different outcomes from the two events was that 9M-MRG only occurred 18 minutes after departure. It actually experienced much higher accelerations, rates of climb/descent, and pitch range over the A330 event. If this happened several hours into the flight after a meal service with many people waiting to use the toilet, I think the outcome would have been very different.

Disagree on that. Rates of climb have been very significant, yes, but although real accelerations have not been published for the 777, noway they were at the QF72's level.

It is also apparent that over 30 AoA spikes were recorded in the FDR (which was limited by the sampling rate), however 3 nose down pitch events were seen. If it was as simple as you were suggesting that it was the protections kicked in, one would assume that a correlation would then exist between all the AoA spikes and the pitch events.

No Sir. And no pilot inputs either, only protections, two of them actually :

1. The famous high angle of attack protection (alpha prot)
2. And the anti pitch-up compensation (I had never heard about that one

before reading the ATSB interim report …)

A total of 42 AoA spikes have been recorded, but only 2 of them had the requested properties to generate an undesired nose-down elevator command.
Please, read page 29 and 30 in the report for more information.