Good God mate, you are a test to one's patience.
Bear with me :

1/ pitot probes freeze. Speed doesn't make any sense to autopilot, consequently autopilot goes KABOOM !
Aircraft goes into alternate mode. No big deal. Just a few protections lost....like stall. Errrrrr ! Trim is still functionning though. You have basically your normal A300 only with fly by wire, but the logic is the same. Pull makes you climb and push.....well, you guessed.
2/ in any airline, trained pilot keeps pitch and thrust AS THEY WERE ! The damn thing was flying a second ago, why on earth shouldn't it fly a second later, speed or no speed indication !
3/ pilot for reasons the majority doesn't want to picture and will therefore hzve its nose rubbed in, pulls nose up. 7000 ft / min at FL 350 ! Some kind of pull ! 10 deg pitch ! Plane bleeds off all its speed and STALLS. by that time, still functionning trim has done its job.......it's trimed the aircraft since somebody was pulling !
4/ by that time, speed is back and shows an horrific 215 kt.....pilot pulls some more adding full thrust making things a lot worse than they already were.
5/ the rest is a long 3 minutes ending by a just horrifying death for 228 people if anyone cares.
Don't tell me they didn't feel anything ! 40 deg bank angle, 11 000 ft / min, some kind of smooth ride !
6/ according to rumours coming from Airbus, once stalled and the fuselage hiding the stab, it was too late.
I heard of some stunt which would have consisted of shutting the engines down, pitch down, relight......blablabla.
The trick was not to let it stall in the first place.
As to the skipper whose rest timing was well.......who could make a sense of the mess he had to face getting out of the bunk almost in his undies ?
Why isn't the french press full of this article when the rest of the world is ? Cuz the french press is a joke whose mission is to report what they're told to report exept maybe for Christophe Barbier. But then......who told him to leak this ?



Finally, this speed BUSS thing that was already in service in other airlines, like LH, is not reliable or very reliable above 25 000 ft, so says the rumour.

3 questions regarding Air France 447
 

1. What were they doing flying through huge CBs when everyone else was going around them???
2. Was the Air Data Ice Protection switched on, and if not, why ???
3. So if you have unreliable airspeed indications, don't you revert to Attitude and Power?

Quote:I write this as a none pilot.
What makes me wonder is why a expirenced and well trained crew did these actions. I simply can not believe they ignored what seems to be SOP and standard pilot knowledge.
For some unknown reason they must have lost thier situation awareness and reacted the way they did with the known consequences.

After the auto pilot disengaged thier understanding of the situation seems to be very different from realtiy.
I hope the recovered data help us to understand why this happened.

Stall warning inop
 

I don't know if someone said, but the Stall Warning was automatically cancel due to auto cancelation of angle of attack sensor because speed was showing bellow 60 kt.

Stall warning is the first and basic warning in aircrafts. Maybe a modern Airbus fell from 37000 ft because the crew didn't know they were stalling. I can imagine the workload, the storming and the IMC falling thinking they were in over speed or high speed stall.

That's my conclusion, it may be wrong but can somebody tell me why no stall warning during a stall?

In Airbus Manuals is said clearly that during a Unruialbe speed RELAY on Stal warning and Overspeed.

747-400 Hi Alt Stall Recovery Training Video
 

Below link shows a sim 747-400 at FL400 cruising with A/P.
The thrust is reduced to approach stall. Note that the the plane pitches up automatically to try and maintain FL400 as power is reduced. Until finally it approaches stall with 5% pitch. In this case the Training Capt (Don Grange ) applies full thrust. This prevents a stall however the A/P is unable to correct its nose up attitude and is unable to increase its IAS. It can only be recovered by a gentle descent.

See link below and skip to about 5:15 min.

CP, #1558
1. ‘They were in a CB’’. There is no evidence that the aircraft was in a CB; the crew had seen and planned / turned to deviate around weather.
2. ‘Air data ice protection on’. A feature of pitot blocking due to ice crystals is that there has to be a heated surface on which some crystals can accumulate / melt. The water becomes the glue for other crystals to build up on, or the water ice mix can stabilize around freezing and block the pipes / vents.
3. ‘Fly attitude / power’. This depends on what the crew see and understand about the situation, and then depending on complex circumstances the ability to fly accurately, all in a very sudden, surprising, and complex situation.

Yes, but is what they saw in front of them what was actually there?

PEI, wouldn't it be true to state that there is no evidence that they weren't in, or in the vicinity of, either a CB or a significant vertical development? I may be stretching the boundary of inference here, but there has been ample anecdotal evidence of possible "blind spots" with Wx radar, from people who operate and operated them. The possibility of locale specific weather/metro surprise remains open, and may remain an unknown forever. The metro conditions along the flight path route were sketched out by Mr. Vasquez. What was locally experienced remains unclear, beyond the BEA release of some conversation about turbulence before the event.

Quote:

---

2. ‘Air data ice protection on’. A feature of pitot blocking due to ice crystals is that there has to be a heated surface on which some crystals can accumulate / melt. The water becomes the glue for other crystals to build up on, or the water ice mix can stabilize around freezing and block the pipes / vents.

---

Gonna save that one in a text file. :)

Hi,

I skipped all .. ROFL cause videos no more available due to copyright claim :)

EDIT:
Thank's for edit !

NigelOnDraft:
My comments Re 'classic 747s' was not meant to suggest that they were impervious to accidents, although the cases you referenced differ quite markedly to the Air France and QANTAS incidents. My point was, does a cascade of automated system failures distract / confuse a pilot from his most important job...flying the aircraft? Are these aircraft too complex? In the QANTAS incident the pilots became very task saturated trying to clear the multitude of system errors, and I wonder how they would have fared had they not had an additional two pilots on the flight-deck that day to assist.

I'm not Airbus bashing BTW, and as Iceman kindly responded to my query, both major manufacturers have their good and bad points. I'm merely posing a question for discussion.

Iceman, thanks for your reply. I'd love to hear your theory, but understand that it's probably not prudent to do so until more info comes to light. Will be interesting to hear how close you were when we do learn more...

Hi,

Tireless I read and reread the BEA note .........

15 seconds after 2H10Min51Sec the speed is coherent
So at 2H11Min06Sec the speed is coherent
It's also noted that the inconsistency between the speeds lasted a little less than ONE minute.
So for the sake of accuracy I will take the "less than ONE minute" as 59Sec.
So this indicate that the inconsistency between speeds appears (the earliest) at 2H10Min07Sec
So before 2H10Min07Sec the speeds are coherent
Or the BEA note that at 2H10Min05Sec the autopilot and auto-thrust disengage and the pilot tell he is in control..
So .. the autopilot and auto-thrust disengage before the apparition of incoherent speeds :confused:
Where is the logic in the BEA chronology ?
Around fifteen seconds later
Why using the word around when they are accurate at the Sec for the other times in the note ...they have the accurate times or not ?
Can we take this BEA note as serious ?

It's time to close this thread now, I'm totally overdosed on the same arguments, and newcomers asking the same questions, until more information is made available, which I frankly doubt will ever happen, IMHO the 'final' report will just be a padded out version of what has already been released. Hope I'm wrong, and it would be nice to have a complete voice transcript.

My thanks to those with Scairbus experience for some insight, but even they differ - recent sidestick 'feel' - or 'no feel' - opinions for instance.

Goodbye.

Hi,

Another already posted PDF :)
http://xa.yimg.com/kq/groups/1048360...0Procedure.pdf
It's ironical that the emphasize is put on the AOA ... when we know that the Airbus A330 had not a AOA indicator :)

Yep

1561 don't work for me either

But I'd like to see it, is there another way?

jcjeant and others

The training video link is fixed.

Lonewolf, “…what they saw in front of them what was actually there”
I think it best to credit the crew with appropriate use of the WXR until evidence is presented otherwise. Plotting the proposed deviation on some weather charts suggest that it was in keeping with the general weather situation.
Also, assuming ice crystals were a major factor; these are more likely to be encountered around Cbs – up to 15nm away, although the Cb core probably has high concentrations. The analogy is that the Cb core is the chimney, and the crystals / grauple is the soot / smoke. The heavier particles fall out of the high-level cloud, whereas the light particles travel downwind in / under the anvil. In both instances, they are not easily detected with WXR (if at all).

Re #1549 “… were they set up to fail? If so, how?”
First I don’t think that we should pursue crew failure – you probably did not mean any negative connotation.
Like most accidents, the findings will probably fall into three broad categories: technical, human, and organisational.
There is insufficient evidence to judge any technical aspects at this time, but there are indications of complexities in the human / technical interface. Not that this implies technical failure or poor design, just different; and thus this requires a different way of looking at systems, different operations, and differences in required human behaviour.

The human behaviour is crucial. The crew were faced with a surprising and complex failure situation, challenged by weather, time, and changing circumstance. Unfortunately we cannot know what they thought, at best we might only speculate, based on what was presented to them, but even that might be less than normally certain from an FDR.

The organisational aspects might focus on airworthiness. The authority knew of the problem but judged the risk of simultaneous ADC failure as being remote (but warranting remedial action), and that the intervening ‘at risk’ period could be mitigated by crew performance, which was supported by evidence of previous events.
This was a failure of risk management, but a failure at or beyond the limits of probability, and based on reasonable assumptions. Yet perhaps a difference which was overlooked was that a modern aircraft with highly augmented controls might not be as easy to fly with pitch /power as previously assumed based on a conventional aircraft, or that the crew may not have had had the appropriate training / experience. Were the regulators ‘set up’; – by life, aviation; probably yes.

How long did it take to read the text above, to understand, to formulate any reaction … 3.5 mins? That’s all that AF447 crew had, and whilst we have had 2 years to define the major themes of the situation and improve our general understanding of systems, weather, operations; the crew only had blanks on the screen.
Such is human performance – variable. We are never set-up, only faced with the limits of our capability in a given situation, assuming first that the situation is understood.

simon001, I have to agree but convincing a pilot to do nothing in a time of panic is really hard!

On the L-1011 there was a situation that could occur only during ground operations. If the stabilizer was moved abruptly a fuselage osculation could be set up. To stop the osculation all you had to do was let go of the column. Lots of luck trying to convince the crew to do nothing!

Poit, which airplane would you rather be in if you were in turbulence, at night, iced up pitot tubes with unreliable airspeed trying to hold pitch and power using the unreliable airspeed checklist? A 747 classic with a yoke and direct throttle or a side stick and a lot of broken automation? Would you pitch the 747 up into a 10 degree plus nose up stall?

That is why I never bid the Airbus so never had to fly it and never learned all the laws, even though it paid more. I never cared if the AP or AT disengaged because the automation was just a help when it worked and when it failed it just increased the workload slightly. I'm thinking pilots are now depending too much on automation and it failing isn't just a small inconvenience.

I am waiting for the BEA to finally tell us what they know because so far the info has been scant so it is hard for us to really know what happened. The CVR would tell a lot of the story and they have all of that.

Just because you don't trust an airplane doesn't necessarily mean you dispise it by the way. I just happened to love and trust my B757 because I had total control over it no matter what the computer thought.

jcjeant:
Excuse me for saying so, but that FAA/Airbus pitch seems pretty elementary to me. About the only aspect a PPL holder might find unfamiliar is the pitch-up moment generated by underwing engines - and even that is obvious after a moment's thought.

So - I must ask why the ATP world has become so disconnected from this very basic flying lesson?

iceman50

Thanks again, iceman50. Only word I'd (gently :)) query is 'emphasised,' though - surely, at the time of AF447, the 'old' drill had been completely replaced by the 'new' one>?

So the old 'nose down and add power carefully' rule wasn't even there to be 'emphasised'? it had been completely replaced by the new - and, in my view, flawed - new 'full power and stay level' one?

xcitation

Thanks, xcitation - shows exactly why the 'standard operating procedure' in operation at the time of AF447 appears to have been flawed - or, at best, inadequate.

So the AF447 PF appears to have done exactly what 'the book' (and his instructors) said at the time - applied TO/GA power and tried to maintain level flight. But, looking at the various press stories, and many comments on this thread, a lot of people (possibly already a majority of people) already think that he was guilty of 'pilot error.'

Maybe the investigators will invent a completely-new accident cause in this case, though - something like 'handbook error'..........? :)

Yet another link...

http://xa.yimg.com/kq/groups/1048360...0Procedure.pdf

Given the assertion of Basil: "the AB should be handled as a video game"... (great post for sure)...
I have a nasty question: Why was the AB logic (software), unaware of its deep-stall condition?
Why did the logic not kicked into Direct Law instead of Alternate? Conditions to do so were not met? The proper parameters weren´t reached would many say... Still, it may had saved the a/c and the guys in it... Or not? A simple: "YOU NEED TO TRIM MANUAL" may had made a difference...
I have a lot of respect to AB, French goverment, investors and all of you in this forum... I´m just addressing some aspects which may go beyond training... And at the end: Life can always surprise you!
I hope that many (I won´t name no-one), will further show some respect for the guys which were doomed in this particular event...
As TheShadow said in his post #1219, (It was #1222 or something like that a while ago... index change here also...): I´m also sick of defenceless pilots who aren´t here to tell what really happened and have to carry the can... Cheers.

Quote:"Why using the word around when they are accurate at the Sec for the other times in the note ...they have the accurate times or not ?
Can we take this BEA note as serious ?"
Not being familiar with the specific FDR output characteristics, it could conceiveably be the FDR data sampling intervals, for instance- write every 5 seconds...

No, we do not get all the details, and unfortunately whoever did the translation into English is not a professional pilot. "Assiette" in French means Pitch, not AOA (which is "incidence" in French).
So, initially the PF raised the nose to 10 dg+ (with less than 7 dg AOA which would have caused an immediate accelerated stall) and at 38000`the nose lowered to around +5 dg. The momentum + the TOGA thrust (which at this altitude is only a modest MCL) then took the aircraft into a deep stall.
At this time the only survivable strategy would have been to pitch the aircraft down to below the horizon.
For the record: even with aft trimmed stab at VS, the A330 does have sufficient nose down authority for this. Only in a fully developed deep stall at very low EAS may this not be available; goes for almost any aircraft type.

As a TRI/TRE I do these hi-altitude stall recovery exercises on a regular basis on A330 and believe me; in a confusing scenario like the actual one, only the most proficient pilots prevail, so please stop the "pilot-factor" blame game.

If the majority of pilots cannot cope with a given situation it is either "natural causes" (like all-engine failure + loss of instruments in ash scenario) or "system failure" (if an operator or manufacturer does not ensure adequate training for a particular situation).

The 747 "sales video" is nice, but misleading. It is true that you can power your way out in level flight (and the A330 actually does this better than the 74) provided you have not stalled. In that case you must regain airflow by lowering the nose and thus decrease the AOA and regain speed.

When building an aircraft, the various design offices try to envision all kinds of contingencies and design a safe aircraft accordingly, but there are limits to human imagination (like when a 74 lost part of the rudder in Japan, or when the same happened to an A330 in the US ).

The events so far seem to be logical but unfortunate. We can only hope that the operators will use this wake up call to go beyond the "minimum required training" policy that is so common today in our cost saving environment. Few pilots come to the airlines with 10 years of fighter experience and the rest have never seen a 10 dg nose down recovery at FL 380.

And for the stupid West Coast vs. TLS comparison: I have stalled wide bodies from both sides: Marginally prefer TLS for its better wing design (and the good red wine you get after the flight testing ;).

Cruise stall recovery
 

In our company we developed the following cruise stall recovery by trial and error in the B747-400 simulator due to the fact that the aircraft would not accelerate in level flight with full power...

Select VS -3000 ft/min
(stick shaker stops almost at once)
When IAS is half way up amber caution range...
Reduce VS in 100 ft/min stages with caution...
When IAS is at top of amber caution range...
Select FLCH to recover in protected mode to cruise alt.

Typical height loss is 2000-2500 feet.

Training Captains with plenty of time in the simulator could with trial and error finesse this to a height loss of 1000 feet but often nibbled the stick shaker...the above method works every time for regular line pilots.

Hi,

FDR record in real time (no delay or blank timing)
So the BEA use of word "around" is deceiving

jcjeant

With respect, I do not think that the use of the word "around" is "deceiving". My background is IT, and when you look at log files from certain software applications the timestamps will be accurate to hundredths or thousandths of seconds.

Therefore, it is not unreasonable to assume that the log files from the DFDR are recording in hundredths or thousandths of seconds intervals, which would mean that for ease the time would be rounded up to the nearest second hence the use of the word "around".

Or maybe it's just been lost in translation from French to English...

PEI, thanks, well said. :ok:

The question you refer to that I learned to ask about mishaps "were they set up to fail?" describes a generic way to look at the human to system to machine interface, and was not directed at the crew of AF 447 personally. What is behind that question is overcoming the throwaway of "OH, it was pilot error" in one mishap or another, and to lead to identifying the influences of systems, conditions, training, and other inputs (like from ATC or unergonomic cockpit set ups) that contribute to things going wrong.

Considering the numerous extended threads on this topic, some common themes keep cropping up: there are some arguments to be made that the crew was set up for a surprise, and worse.

If you look at it from the perspective of Team Air France, the flight failed to do as intended: deliver plane and pax to Paris. Would a more useful form of that question be: "where were the seeds of mission failure sown?"

I suggest that's the driving question behind BEA's difficult task.

Hi,

I disagree this to justify the use of word "around" by the BEA
Read again the BEA note please.
For all the other timings BEA use **H**Min**Sec
Why use the word around for another important timing ?
Something lost in the translation ? .. that's possible .. but not acceptable from a organization like the BEA ....
They are not writing romances .. they are writing reports and notes that can have in the futur .. consequences on the life of many people...

PEI 3721
Without the release of the full CVR transcript, there is no way of knowing what they saw, or didn't see painted on their radar. We do know what the Lufthansa, Iberia, and AF459 crews saw on their radars that night because they have told the BEA.

As for the Cb, the satellite imagery of 02h07 as analyzed by Meteo France (included in the first interim BEA report) indicates at 02h10 off their starboard wing there was a rather cold cloud top:
I assume you don't need a translator for "cumulonimbus".

Tim Vasquez has this to say in his June 1 2011 re-analysis,
Air France 447 - AFR447 - A detailed meteorological analysis - Satellite and weather data

Could it be that they saw that SOME indications were incorrect and assumed ALL instruments were suspect/wrong? And continued - seat of the pants

Not likely, Vovachan.

Type training typically includes systems understanding and working knowledge. The "all or nothing" idea is at odds with how each instrument is fed data by different systems, something pilots who fly professionally have to understand to pass their exams and type ratings.

Bad weather
 

I would add that the pilot reduced cruise speed from mach .82 to .80 which is condusive with passing through bad weather. The purpose of this slowing is to reduce stress forces on the air frame. Secondly the BEA clearly states that the pilots advised cabin crew of turbulence. Also stated was air temperature increase which indicates updrafts and turbulent weather.

I am not a pilot but I have an MS in Aerospace Engineering and an MS in Aeronautical Engineering. I have worked for over 15 years in the aerospace industry. My main occupation has been control law design for satellites - this is different from flight control SW for atmospheric flight but there are many common issues. Today I work in a company that measures the complexity of systems (air traffic systems, power plants, IT systems and SW).

Modern airliners - especially those that fly-by-wire - are full of SW (4+ million lines of code is a commonly cited figure). In practice, pilots "train to fly the SW", not the aircraft. I agree, it is a strong statement to make but when I see pilots posting in this thread that the AoA is not something you necessarily want to be displayed in a cockpit it kind of confirms my point.

But the point is this. I work in measuring the complexity of (SW) systems and I can state that when you have 4+ million lines of code:

1. There is a huge amount of circumstances (combinations of operating conditions) are never tested.
2. To test a SW system of that size you need another SW system that is at least as large as the one you're testing.
3. Because high complexity implies the capacity to deliver surprising behavior, SW systems of that size are almost bound to do so.
4. There are some misconceptions when it comes to systems of systems:
- if you have 100 components then you can get at the most 100 headaches. In actual fact, the number is orders of magnitude larger.
- the worst condition for a given system is NOT that which corresponds to all variables operating each at its operating limits. Sometimes, combinations of values well within the design bounds correspond to the worst-case scenario
- if you have 100 great components a system made of these components is also great.
5. High complexity implies high fragility. If we continue to manufacture more complex SW and more "intelligent" aircraft, these will cause an increasing number of accidents.

My opinion, based simply on my own professional experience and knowledge, is that we are in the hands of computers and that the trend will be to go in that direction even more. I used to work for a computer HW company in the late 1990s. We had a problem with our operating system on one of our models (which was already on the market). We put in one meeting room all our experts on OUR operating system. Their knowledge, when added up, was estimated to cover about 99% of OUR own product! Now 1% of a complex product/system is still something terribly huge. That was in the 1990s, now things are even worse!

Could we move this thread to Good Housekeeping Magazine's website, maybe, or Rolling Stone's? It is of no more value on an aviation forum.

Lonewolf, re "were they set up to fail?" # 1582
In that sense, they (us, the industry), were ‘set up’ to fail. However, ‘set up’ could imply forethought / previous knowledge, which might be, or its absence might be, a major contributor to the accident.

With hindsight, many posts question “why did/didn’t they” … etc, etc; whereas if the industry had foreseen these issues then the accident might have been avoided, e.g. a complex interaction of system design and human reaction, changing economic climate, social changes in operations and training, expectation, peer pressure.
Alternatively, where the industry considers issues, human judgement could still decide not to act – the risk is acceptable, e.g. multiple pitot icing resulting in LOC. Much of this is driven but public expectation; - and we are a very safe industry, but beware the seeds of complacency.

The above reflects normal human behaviour; humans are irrational. We don’t foresee every eventuality, systems cannot be tested rigorously, particularly where there is human interaction, and where problems are identified safety vs practicality are often judged to balance.

In this sense, AF 447 may have been an accident too far. Yet there have been other, similar situations where the humans rescued the situation (DC-10 Sioux City, A300 Baghdad). The human behaviour in all of these was identical – the humans did their best in the circumstances – as they saw the situation; only with hindsight is an event judged, and on occasion, ‘best’ is not good enough.
I prefer to avoid hindsight, instead look to see how and why human performance varies, and hope to establish what might be done to improve human performance or change the nature of circumstances to be faced (technical / social); but this probably requires some forethought, which is where the ‘seeds of failure’ might be found.

Saturn V, I suspect that we are interpreting words differently.
What I posted was “the crew had seen and planned / turned to deviate around weather”, which was based on details released so far.
I agree we do not know what exactly the crew saw, but circumstantial evidence suggests that the aircraft was not ‘in’ the core of a CB, although it was in an area of convective weather.
In this regard I disagree with Tim Vasquez’s conclusion “This indicates that the aircraft was flying through convective clouds at about 0150 UTC and again from 0158 UTC onward.” Implying, (my interpretation) flying through a Cb core.
From personal experience – ‘in’ and around Cbs – I would be very surprised if the reported conversations and aircraft parameters originate from a situation in a Cb core, but transiting an area of convective clouds would be understandable.
IMHO, the aircraft was below a cloud layer or in high level cirrus (anvil) in a situation similar to that shown in VH-EBA Incident (picture on page 11) where there were high cloud tops in an area of convective weather – a classic ice crystal situation.

Vovachan; lonewolf, re “assumed ALL instruments were suspect/wrong”, but ‘not likely’.
Not likely, but don’t discard the thought. See another A330 Incident where unreliable airspeed (pitot probes freezing) resulted in an apparent change in altitude (assumed low speed correction factor). Also, note the effects in the erroneous change in TAT (TAT probe freezing). What haven’t been established so far are the effects of ‘rapidly’ changing speed and temperature on other computations in the ADC and possibly in the IRS module.

If the crew’s perception was of a ‘failure’ of airspeed, sudden drops in altitude, and perhaps rapid changes in VS, then concluding that there was a ‘display’ failure (the computation behind displayed parameters) would be logical.

xcitation “Also stated was air temperature increase which indicates updrafts and turbulent weather”.
The ‘increasing’ temperature could have been due to the TAT probe blocking with ice crystals, again see the A330 incident above.

Steed

1581 Agree

Spurious accuracy does not make one data set innately superior to another

"All time data here rounded to x dp" could be held to be a clumsy use of English and "around" could be held to be held to be more succinct. I personally prefer the former.

I suspect different authors were at work rather than Machiavelli.

http://www.pprune.org/rumours-news/4...ml#post6505825
safetypee:

Roger your post. I had asked, in this thread or the other, about TAT probes being ice obstructed, and you provide me an answer. Report saved FFR. Thanks.
300 feet off. (The ATSB document you linked to) Not quite the altimeter unwinding, is it? :) However, perhaps the point you are making is that seeing alt low a few hundred feet (from an iced TAT and iced pitot probe) prompts pilot to make what is initially a small correction to climb back to FL350? Is that what you were getting at?
But not the attitude indicator, which is what I had in mind primarily when I made my response. Sorry for the ambiguity, I had thought I was addressing how pilots tend to know which systems influence which cockpit gauge ... but I guess I did a poor job.

ADIRU includes IRU. IRU does not use airmass data to display attitude. Have I missed something?

I may have asked that in the other thread. Thanks! :)

The Captain says "The temperature is not falling as fast as we expected".

Pertinent?

Lonewolf 50 Not all seeds are immediately obvious. Nearly impossible to disprove, parts of the system soft/firmware might have been altered either by mistake or or purpose, maybe with the deliberate intention of causing this crash. Now that systems behave according to rules laid down in software they must be a prime candidate for interference by those who intend harm. Perhaps it hasn't yet happened somewhere, but for certain it will.

Oh, yes, it HAS happened. Erebus. TE901 November 1979. And, as Gordon Vette pointed out, there were a number of factors that came together to turn an incident into a tragedy.