AF447 wreckage found

[BOAC]

MBear - they did not need to know what had caused the loss of IAS indication. To apply backstick with a ridiculously low IAS flies in the face of any logic. I still find it difficult to accept any trained pilot would do it.

Step - "160 pages in, and this should have been said--and of course has been any number of times--maybe 150 pages ago and this thread closed. Deal with it".- you are forgetting the 150 times per thread on previous threads.

Why is the biggest question and is the priority. It indicates a major chasm in AF training - and I fear probably across other AB companies too.

[Safety Concerns]

It indicates a major chasm in AF training - and I fear probably across other AB companies too.

Even after the stall manifested by the rapid heading change (bank attitude) and the sudden descent, the FLIGHT CREW FAILED TO RECOGNIZE the problem for a number of seconds. THEY CONTINUED TO APPLY BACK PRESSURE ON THE CONTROL COLUMN WHICH KEPT THE AIRCRAFT AT A HIGH ANGLE OF ATTACK.

Boeing 727 Accident Conclusions:

The aircraft accumulated sufficient ice during its flight to block the drain holes and total pressure inlet ports. Static ports were not affected.

The flightcrew misconstrued the operation of the stall warning STICK SHAKER as mach buffet.

The flightcrew continued to increase the nose up attitude of the aircraft following the operation of the stick shaker

Following the stall the aircraft entered into a right spiralling dive at a high rate of descent. Throughout the descent the flightcrew reacted primarily to airspeed and rate of descent indications instead of attitude indications and this failed to initiate recovery techniques and procedures.

In an effort to recover the aircraft from the high rate of descent the flightcrew exerted excessive pull forces on the control column.

CAUSE:

The NTSB determines that the probable cause of this accident was the loss of control of the aircraft because the flightcrew failed to recognize and correct the aircraft high angle of attack and low speed stall. The stall was precipitated by the flightcrews improper reaction to erroneous airspeed and mach indications which had resulted from a blockage of the pitot heads by atmospheric ice.

Sound familiar. Now perhaps BOAC when you reread Aeroperu, Birginair and several others, you could perhaps expand on your fear that this is something to do with airbus.

The truth hurts but you need to look closer to home for this one. It is the mark I human being at fault, nothing else.

[RetiredF4]

Let go of SS, Iceman50

iceman50

However during the entry the STALL warning is continually "sounding" and even if you had just let go of the sidestick, after the initial input, the stall warning stops and an extreme attitude is NOT achieved. You have to HOLD it in.

I question that, depending on your undestanding of "initial input". If you define that as before the pitch reached more than 5°, i might accept.

In Alt2B without protections the FCP follows an loadfactor demand. If, for example, the initial loadfactor demand called for 1,5 g´s and that resulted in an pitch attitude of 15°, releasing of SS input would now demand a loadfactor of 1 g. This new load factor demand would lead to maintaining the 15° pitch regardless of speed decay.
Although if no further input for a NU demand will be made on the SS (in neutral as you say), the FCP would continue to drive the elevators NU and start to trim the THS NU to maintain this one g equaling the pitch at SS release in the decaying speed situation. Result will be a stall with 15° pitch, elevators and THS full nose up.

Does this sound familiar?

What you described would be the behaviour of a conventional aircraft, where elevators return to neutral when NU input is terminated and with no trim input the aircraft would answer the decreasing speed with a decrease in pitch and climb rate to find its equilibrium / stable state of flight again.

Or it would be the behaviour of a FBW aircraft with protections working.

I think you are aware of that, i just wanted it to make clear for other readers.
If i´m wrong, please post.

[Lemain]

MBear - they did not need to know what had caused the loss of IAS indication. To apply backstick with a ridiculously low IAS flies in the face of any logic. I still find it difficult to accept any trained pilot would do it.

Clearly they were trained pilots. Let's assume they weren't incapacitated by drugs or medical problems (?) what could conceivably have caused trained pilots to do just that? Something made them make those decisions.

[iceman50]

RetiredF4

Hi Franzl,

It was "looked" at in ALT Law and to get anywhere near 15 degrees will take a lot of sustained effort. It also looks way wrong on the PFD.

[cwatters]

Safety Concerns writes...

The truth hurts but you need to look closer to home for this one. It is the mark I human being at fault, nothing else.

Well yes but isn't it the job of aircraft designers and pilot trainers to look at previous instances of human failure and try to reduce the chances of other people making the same mistake again?

How long has it been known that pilots sometimes fail to recognise they are stalled? The examples you and others provided clearly show it's happened before.

Could/should something have been done about the issue sooner? Should something be done now? Would it really cost much? Have accidents become so rare that even relatively cheap changes fail cost v benifit analysis?

[RetiredF4]

Re iceman50

Hi Franzl,

It was "looked" at in ALT Law and to get anywhere near 15 degrees will take a lot of sustained effort. It also looks way wrong on the PFD.

Ice

But that is, what happened here with AF447. They got way over 5° and stalled.

2:10:08 = pitch 5°
2:10:15 = pitch 10°
2:10:30 = pitch 13°
2:11:00 = pitch 15°
2:11:08 = pitch max pitch about 17°

And releaving SS at that moment would not have changed anything to a positive outcome. Releasing at less pitch than 15° would only lengthen the timeframe till stall would occur if not dealt with the problem by SS ND.

So my question was (and still is), to what time/ pitch you reference your term "after the initial pitch up"?
Even the 5° pitch would not be good for endless time, as same as stated above would apply. No protection, therefore maintaining 5° pitch until speed is below stall speed and same time elevators and THS full NU. It would take considerable more time and would leave more time to counteract though.

It´s important to understand aerodynamic and energy management also in an FBW protectet aircraft, when those protections and ATHR go southbound.

[Safety Concerns]

Well yes but isn't it the job of aircraft designers and pilot trainers to look at previous instances of human failure and try to reduce the chances of other people making the same mistake again?

Yes absolutely. But the issue here is being blurred (as always) by unnecessary and irrelevant references to manufacturers and one manufacturer in particular.

It may surprise many of you but it is a fact that most airspeed related accidents have been in Boeings whereas most airspeed related incidents have been in Airbus's. Which would you prefer, an accident or an incident?

I haven't witnessed any great cries for design change on the Boeings.

So remove the emotion, argue facts, tune in with your aircraft and the designers will work with you to improve safety.

[Lonewolf_50]

Safety Concerns, in re this:

The truth hurts but you need to look closer to home for this one. It is the mark I human being at fault, nothing else.

Are you referring to the human beings who failed to replace the Thales pitot probes, even though an airworthiness directive had been issued to that effect?
Are you referring to the human beings who are in charge of training at AF?
Are you referring to the Captain of AF 447, and his decisions?
Are you referring to the PNF who didn't take the controls?
Are you referring to the PF who held a high nose attitude, and seems to have applied a low altitude solution to a high altitude problem? (Go back to the training, and how you reward people for various performance.)
Are you referring to the human beings who believed that disabling stall warning when the aircraft is stalled (< 60 kts) while airborne is a good design approach?

Which human beings are you referring to, Safety Concerns?

[Rananim]

The truth hurts but you need to look closer to home for this one. It is the mark I human being at fault, nothing else.

Safety Concerns

I hope by "human" you meant to include the designers because if not,its grossly unfair to the pilots.Are you really saying that the interface design contributed nothing to the probable cause whatsoever?
An experienced Airbus pilot left a post saying how sensitive SS control was at even low altitude.What about high altitude with little buffet margin and throw in moderate(perhaps worse) turbulence..what then?How easy would it be to overcontrol then?The forearm must rest on an armrest with the wrist as the pivot point for SS control in an Airbus.Great for small precise control inputs in smooth air.But what about during a high alt upset in rough air when the forearm might become dislodged.The stick isnt between your legs,its off to one side.
And then theres no feel feedback.And the PNF cant see what the PF is commanding on the stick.Hes out of the loop so its effectively a single crew response.The PNF can override and try his luck but theres no way for both pilots to work it in tandem.They can override each other or they can work in opposition with the computer adding the inputs algebraically or cancelling each other out.And who knows who's really in control?The "priority" audio call and the visual green/red arrow on the glareshield might be fine in a normal situation.But in a bad situation with turbulence and with loads of ECAM warnings?These channels get dumped quickly.You just wouldnt get this in a conventional aircraft.YOU SEE BOTH STICKS.YOU SEE WHAT THE OTHER GUY IS DOING WITH HIS STICK.YOU WORK IT TOGETHER IN EXTREME CASES WITHOUT ANY NEED FOR AUDITORY/VISUAL FEEDBACK.ITS ALL TACTILE.

And then the autotrim cutting out with THS at max ANU.Do you think pilots have time in a bad situation to look at the ECAM and start deciphering what effect the changing laws have on what theyre doing?If they can remember.ALT LAW..right, I have no stall warning protection.ABNORMAL LAW..right, trim is manual.THEY FLY THE PLANE FIRST AND FOREMOST.And the stall warning inhibit?Going off when the aircraft was in a deep stall?This is acceptable design is it?All this complex and frankly suspect interface design didnt have any effect whatsoever on the outcome??

The Airbus is a video game,nothing more.In normal ops,Im prepared to believe its the most wonderful thing since slice bread.

[Safety Concerns]

It is quite incredible how far off track you guys have become.

The design interface played no more of a role in AF447 as did Boeings design interface in NW6231 back in 1974.

Everything posted in the previous two posts as in BOAC's silly slip up highlights nothing more than YOUR personal refusal to get in tune with the aircraft. The proof is that your clarion calls for change would have us believe that stick shakers and feedback and no electronic software would have resulted in a different outcome.

WAKE UP CALL: Aeroperu, Birgenair, NW 6231. Thats 3 Boeings so why haven't you called for major design changes on them?

I quote again the President of the Flight Safety Foundation

"This should have resulted in a log entry"

[RetiredF4]

Re

And then the autotrim cutting out with THS at max ANU.Do you think pilots have time in a bad situation to look at the ECAM and start deciphering what effect the changing laws have on what theyre doing?If they can remember.ALT LAW..right, I have no stall warning protection.ABNORMAL LAW..right, trim is manual.THEY FLY THE PLANE FIRST AND FOREMOST.And the stall warning inhibit?Going off when the aircraft was in a deep stall?This is acceptable design is it?All this complex and frankly suspect interface design didnt have any effect whatsoever on the outcome??

Lets not drift off the truth.

Automatic trim was working in Alternate Law, only in direct law autotrim is not available. Autotrim was not cutting out, the situation with loadfactor demand by SS and decreasing speed caused the NU trim to travel full up and also kept it there. The crew did not understand that and it looks that after some hundred of pages it´s still not understood.

Safety Concerns
It is quite incredible how far off track you guys have become.

That is not true, pilots want tactile feedback and better machine- human interface. That is a legit demand of the people who have to fly those aircraft under (unfortunately only) abnormal conditions. .

As i stated before, adopt to that demand and design something new and better instead denying the need for improvement. Its the task of the manufacturers´with the designers and engineers to make apropriate recomendations for those necessary improvements. The pilot comunity will bring the old reference (stick and all other old but functioning input tools) as an way to describe the need for change in layman terms, not as a demand that it has to be in the exact old way.

I told you that before, and i thought you got it and would be able to communicate in the future on that basis. Instead you fall back in the old A vs. B and old vs new saga.

That does not take care on the aim to improve safety.

[DozyWannabe]

Originally Posted by Safety Concerns

... when you reread Aeroperu, Birginair and several others, you could perhaps expand on your fear that this is something to do with airbus.

It's not BOAC's fault - the received wisdom in the piloting community is that the dependence on automation and company edicts to use the automatics wherever possible started with the introduction of the A320. A little digging will reveal that this is not the case, with full-featured FMS being around since the '70s and widespread on the line with the introduction of the 757 and 767 in the late '70s/early '80s.

It's possible that it became even more widespread later on, but I'd argue that probably has more to do with the retirement of the "old school" management and executive levels, many of whom had worked their way up through the airline, or indeed founded it - and their replacement with the newer generation of MBA grads who were more purely bottom-line orientated. Unfortunately this also happened to coincide with the introduction on the A320 in the late '80s and early '90s, which may have served to reinforce the perception.

[Safety Concerns]

I told you that before, and i thought you got it and would be able to communicate in the future on that basis. Instead you fall back in the old A vs. B and old vs new saga.

That does not take care on the aim to improve safety.

Exactly but it is pilots who have posted airbus attack after airbus attack even though Boeing has suffered more accidents under similar conditions

And then the autotrim cutting out with THS at max ANU.Do you think pilots have time in a bad situation to look at the ECAM and start deciphering what effect the changing laws have on what theyre doing?If they can remember.ALT LAW..right, I have no stall warning protection.ABNORMAL LAW..right, trim is manual.THEY FLY THE PLANE FIRST AND FOREMOST.And the stall warning inhibit?Going off when the aircraft was in a deep stall?This is acceptable design is it?All this complex and frankly suspect interface design didnt have any effect whatsoever on the outcome??

To apply backstick with a ridiculously low IAS flies in the face of any logic. It indicates a major chasm in AF training - and I fear probably across other AB companies too.

To quote just a few of the more ridiculous comments.

Analogue aircraft suffered the same outcomes under the same conditions. Yet safety is better today than then. Going back won't achieve anything as won't the constant consistent misinformed uneducated criticism of one manufacturer over the other.

That message still aligns with retired f4

[Mac the Knife]

"Something made them make those decisions."

From the CVR and their subsequent actions it appears that the UAS indications with sudden AP disconnection and reversion to alternate law took them completely by surprise. This sort of behavior from the aircraft was something totally unexpected and for which they were emotionally unprepared. They were "gobsmacked" and and what training they did have, just went out of the window - no actioning of lists, no attempt at analysis, no rational response at all, just fiddling in increasing confusion with the primary flight controls as more and more warning messages flashed and audible alarms blared on and off as the situation deteriorated.

Finally they were completely lost as the PF admitted ("I have no control of the aircraft") with no coherent mental image of the situation - even the altimeter winding rapidly down seemed unreal, and the Captain appeared on the scene far too late to compose his own perception or take any meaningful action.

A tragedy composed of overconfident automation design compounded by pilot complacency and inadequate systems training.

[BOAC]

Originally Posted by Dozy

Unfortunately this also happened to coincide with the introduction on the A320 in the late '80s and early '90s, which may have served to reinforce the perception.

- indeed it did and made it worse, and before that all pilots KNEW that they could stall an aircraft (and did as we know) by 'mishandling'. Following that they were told they could not (I have lost count of the number of the blatherings about it I heard from those operators in the 80's) and unfortunately a large number believed it. I hope that cult memory is slowly being eradicated, and as I said before, that both AB and AB pilots are having some serious thoughts about the way they present and operate the type. I suspect/hope this and the PGF crash have opened a few eyes. The parallel I draw is the driver I saw last winter here who, dazzled by the brilliance of the 'perfect' ABS in his car, was amazed when it let him slide into another car on sheet ice.

[RetiredF4]

Safety Concern

Exactly but it is pilots who have posted airbus attack after airbus attack even though Boeing has suffered more accidents under similar conditions

To quote just a few of the more ridiculous comments.

I tend to agree with you, although i would not call them ridicolous but far fetched or not quite derived from the necessary system understanding. And that is one of the training problems, not a personal misbehaviour.

Not all pilots make those comments, some originate out of the early days of the discussion where the knowledge base was still narrow and lot of speculation was involved. If you have an an understanding of pilots work and believe their desire for an improvement, it should be possible to answer in a more positive way instead of total opposition. F.e. like thinking about how those systems can be improved.

Then the discussion changes from "why should we improve the system" to "how can we improve the system".

And the term "system" i reference to all involved parties, including pilots and including manufacturers.

[Safety Concerns]

The parallel I draw is the driver I saw last winter here who, dazzled by the brilliance of the 'perfect' ABS in his car, was amazed when it let him slide into another car on sheet ice.

you can draw this parallel as long as it is done on the following basis:

30 years ago 100 cars a winter were sliding into other cars on sheet ice. Today we have reduced that to 10. Our aim is to reduce further.

You cannot draw this parallel if you do it on the basis that Honda's ABS is flawed because I want my own foot to do the braking as in my Chevy whilst quietly overlooking the small issue of more accidents in a chevy.

[Lyman]

The a/c lost a/p, changed FlghtLaw, and required handling.

The LAW eliminates PITCH protection, and the a/c is considered lively, certainly more active than NORMAL.


No judgment, but a starting point, and one suspiciously missing some easy to include safety features, and training changes.

Judgment: There is confusion, among the people who fly her, whether the correct action is:

1. Resist Manual Flight, be patient.

2. Set 5 degrees NOSE UP. (See 1, above)

3. Start eliminating Warnings via the "BOOK".


Unless and until these points are addressed, and by addressed I mean Remedied, not mitigated, the rest is distraction.

[Safety Concerns]

Where is the difference between that and NW6231?