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AF 447 Thread No. 11

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AF 447 Thread No. 11

Old 16th Jun 2013, 16:48
  #61 (permalink)  
 
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We probably could achieve a similar outcome with a less colourful description
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Old 16th Jun 2013, 22:13
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Originally Posted by busTRE
An airbus can stall in normal law
Just need two AoA probes to freeze at a similar angle ... High angle protection no more but normal law still.

An outfit I am 'familiar with' had just such an incident, full back stick on receipt of the hard 'pull up' just saved them (rad alt at the peak around 40ft).
Surely a report must be somewhere ... or is it only AF to have their 'adventures' exposed ?
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Old 16th Jun 2013, 22:52
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CONFiture

Yeah, I said an airbus CAN stall in normal law!

Don't know if the report is in the public domain. But I do know that the investigation team produced profiles for the escape maneuvre which included 'average' airline wide profiles for comparison which didn't clear the terrain.
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Old 16th Jun 2013, 23:30
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Originally Posted by busTRE
You think a guy nudging the stick shaker is flying a max alpha manuevre as efficiently as one nailing alpha-max with EFCS?
and
Don't know if the report is in the public domain. But I do know that the investigation team produced profiles for the escape maneuvre which included 'average' airline wide profiles for comparison which didn't clear the terrain.
I don't understand why you gentlemen think you do not need AOA indicators.

Of course you cannot fly as accurately by just triggering the stick shaker as you could fly with an actual AOA indicator directly in front of you, but if you had an AOA indicator and used it, your performance should not be far different than the EFCS max AOA performance.

In the situation just mentioned by CONF iture, there would be unreasonable AOA values staring you in the face as you decelerated. You would have to be asleep to miss it.
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Old 16th Jun 2013, 23:31
  #65 (permalink)  
 
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Inhibition of stall warning. Well Ok, see where the designers where going...
I used to fly Zlin 142 at 180 alpha (very briefly) with stall warning ringer silent, yet a couple of seconds later it went off quite happily as I botched the exit from Immelman.

Now, can we accept that alpha probes need to have some airflow to work reliably or do we keep on harping that they have to work perfectly from zero kt to Mmo, which is quite a wishful thinking?

Affirm mode by changing some colours on the FD ? In a crisis I am supposed to notice and swing my mind around to that ?
Sigh. What was the initial crisis?

Let the THS go way beyond normal limits and not scream about it ?
Sigh again. What is the normal THS limit? Did THS follow the pilot's stick order, yea or nay?

Have a SOP which says blank FD when the software could automatically do it ?
Fictional software. As developed and certified - can't.

Need to crowbar the logic in some situations.
When one's notions are both at odds with official documents and totally disproved by reality and yet still there is urge to promulgate them on internet fora, crowbaring the logic is quite appropriate.

How about a 'Ghastly Silence' mode
Worked well around here until a couple of days ago.

The pilots need effectively to understand 2/3 'philosophies' - slightly different 'rules of flying' in each law, and to be able to 'switch' seamlessly from one to the other, probably when the is hitting the fan. An easy task for a 'HAL' with loads'a lines of code, but for we mere mortals....................
Obviously, my umpteen attempts at explaining the protections were just too technical. Let me try it this way: why do you think Airbus pilot needs to understand what you have labeled "2/3 philosophies"? Why would the Airbus pilot need to know anything about protections at all (besides them being covered in FCOM and there being legal requirement to know one's manuals)?

why was the stick subsequently held back, do you think?
Panic.

An Airbus is not worse than any other design, but it is not better just because of its design either.
So sayst thou.

I don't want to enter the statistics debate again, but another FBW design has a better safety record.
Not necessarily just because it's a FBW of different flavour. Part of it is certainly attributable to her price tag combined with date of service entry - she just didn't trickle down yet to lower tiers operators.

I have flown the AB, the T7 and the MD11. All of them FBW
Since when LSAS counts as FBW?

It is this myth of some invulnerability of Airbus that cultivates pilots who fly escape manoeuvres with full stick back in any situation.
Escape from what? Under what circumstances?

A start would be to stop with such dumb assertions that Airbus does this and that better than others.
There is absolutely no realistic doubt that hard alpha protected aeroplane (such as Embraer) performs better in windshear/ground escapes than those with overridable prots. Why would anyone call assertion stemming from flight test results dumb?

What we need is a simple independent back-up to all the electronics like i.e. a pneumatically (wind) driven gyroscopic horizon and a unprocessed access to the flight controls.
Where would you power your pneumatic AH from with dual bleed failure? Why ISIS doesn't satisfy you? Did you ever hear about direct law, which is exactly what you propose but is in operation since 1988? Why do you feel the urge right now to denigrate alternate law?

I guess he thought that since he was definitely airborne that it was necessary to pull fully back.
Well, since you have so nicely copypasted the procedure 'tis a pity you didn't include the title of it.

It's low level windshear encounter.

What does it have to do with cruise, beats me. Lest you want to suggest that it is indeed difficult to tell the difference between low level maneuvering and cruise flight.

We dinosaurs were taught to "respect the stick shaker" during these manoeuvres. Airbus doesn't fit one
Even the report confirmed it is pretty superfluous as natural buffet is quite pronounced.

just another audio warning on top of constant "C chord" altitude deviation warning.
And it says : "STALL STALL STALL STALL STALL STALL". Pretty unambiguous, eh?

Just need two AoA probes to freeze at a similar angle
Pray tell, how did it occur?

High angle protection no more but normal law still.
Parbleu! Wasn't there any indication in cockpit something wasn't quite right?
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Old 16th Jun 2013, 23:55
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A student pilot would not have had a problem recoverying from his instructors guidance.
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Old 17th Jun 2013, 00:14
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How do I know they had no ATT info?
Well, I'm not so sure you do. If the aircraft had remained airborne for another 2 seconds, the words the Capt was in the process of uttering would probably have confirmed the issue - one way or the other.
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Old 17th Jun 2013, 02:35
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Another AoA disciple speaks

I welcome USMC to the fray. Seems to be from the "next generation" from 'bird and I, but has the same feelings/beliefs about AoA as RetiredF4 and other folks here that have used HUDs and AoA indicators for thousands of landings ( not hours, considering our mission lengths),

It is true that you can use the FPV relatonship to the ship's "boresight" to determine AoA. But why go thru that when you can have a simple display that shows your AoA WRT to stall or best approach AoA ( speed will vary depending upon gross weight and configuration)?. My leading edge flap failure video is old and grainy, but you can easily see it WRT to the pitch lines, and both are related to the real world via an inertial system, with no regard for frozen speed/altitude sensors. AoA doofers are still working. We can laugh at my mistakes near the end, but I corrected enough to save the jet and my skinny butt. The AoA is that braket below the FPV, and had I tried to reach the dersired AoA for normal approach, I would have lost roll authority, so I flew at a lower AoA. As with the A-7, F-14, F-16, F-15, AV-8, F-18, F-22, and now F-35 you pull to get the braket even with the FPV, or push. My upward FPV change near the end was due to extra power, as I had started down quickly when putting out speed brakes from habit ( not good).

http://www.sluf.org/misc_pages/lef-landing.m4v

So much for the basics of using AoA and FPV.

I'll guarantee that the AF447 troops would have noticed their FPV WRT to the pitch lines and realized that the FPV was not going up and that AoA was above the stall AoA. Pitch attitude be damned.

No doubt the unreliable speed was a factor, as was trusting the "protections" when in a back-up flight control law. But inertial vectors and operable AoA displays would possibly have saved the day.
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Old 17th Jun 2013, 07:55
  #69 (permalink)  
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Originally Posted by Clandestino
Obviously, my umpteen attempts at explaining the protections were just too technical. Let me try it this way: why do you think Airbus pilot needs to understand what you have labeled "2/3 philosophies"? Why would the Airbus pilot need to know anything about protections at all (besides them being covered in FCOM and there being legal requirement to know one's manuals)?
- sorry, they still are - I do not understand the question.

Regarding AoA and the Oozlum bird. Forget the AoA. It would take enormous training input and costs no-one will justify, and can easily be 'missed' in a panic too - yet another gauge. All we need is pilots who understand basic flying, and that a PITCH attitude of 17 degrees at 38000' is just silly. I believe they never went below 5 degrees? 3 instruments already there, apparently working, displaying this, and used for 'basic flying'. End of? The challenge is 'why'?
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Old 17th Jun 2013, 09:41
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BOAC

Agree. Introducing AoA would add a layer of complexity that will probably produce more problems than it solves.

Natstrackalpha

How do I know they had no ATT info?

Because the PFD said S&L and the nose was pointing up wards.
What utter balloney. You know nothing of the sort and how the hell do you know the real attitude was different from that on the ATT indicator? Please do tell.

It's embarrassing sometimes.

Show us the exact quote from the report

Last edited by busTRE; 17th Jun 2013 at 09:42.
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Old 17th Jun 2013, 09:49
  #71 (permalink)  
 
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Are we talking about AF over Atlantic in bad wx that disappeared and was pulled out some time later . . . ? A330?
absolute c****n

Now read this carefully. WHERE IN THE REPORT DOES IT SAY THAT THE PFD WAS READING S&L WITH THE NOSE POINTING UP. Show me where it says that because I can't find it.

Last edited by busTRE; 17th Jun 2013 at 09:51.
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Old 17th Jun 2013, 10:12
  #72 (permalink)  
 
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Did I invent it?
Yes you did. It does NOT say this in the report and you are full of it.
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Old 17th Jun 2013, 10:17
  #73 (permalink)  
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Originally Posted by Natstrackalpha
- Well, where did I get this from?
- are you talking ("PFD diplaying S&L") about the brief interval between zooming up at several thousand feet per minute and zooming down at around 10,000 fpm? Yes, they probably were "S&L" for a moment or two - it is called the 'apogee'.
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Old 17th Jun 2013, 10:40
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Originally Posted by BOAC View Post
The pilots need effectively to understand 2/3 'philosophies' - slightly different 'rules of flying' in each law, and to be able to 'switch' seamlessly from one to the other, probably when the is hitting the fan. An easy task for a 'HAL' with loads'a lines of code, but for we mere mortals....................
Hi BOAC,

I don't want to interfer to much in your discussion with HN39, abut still I'm puzzled by your comment about the different laws.

I mean, aren't crew supposed to be able to adapt to slightly different 'rules of flying'? Isn't that the very purpose of "keeping" crews and not letting computers alone in the front end?
- Crews are able to understand (and manage) an engine failure, resulting in slightly different 'rules of flying': less thrust available and dissimetry.
- Crews are able to understand (and manage) a fuel leak or a depressurization, resulting in slightly different 'rules of flying': range is shortened, altitude is limited (if depressurization).

Why would crews not be able to understand (and manage) the slightly different 'rules of flying' that some sensor failure may cause, such as the loss of protections caused by law reversion?

I fail to see the fundamental difference you seem to see between those different failures.
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Old 17th Jun 2013, 11:06
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Why would crews not be able to understand (and manage) the slightly different 'rules of flying' that some sensor failure may cause, such as the loss of protections caused by law reversion?
AZR

Its not the crew, the airlines or the training. All airlines train and all crews are trained - it is the type of training that needs to be reviewed.
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Old 17th Jun 2013, 11:13
  #76 (permalink)  
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AZR - I agree with NTA on that and have said it before many times. I don't know the answer to your question, but in the absence of any logical explanation for AB events such as 447 involving 'failure' of the protection systems, I am asking. A kind of Occam's razor, I suppose?
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Old 17th Jun 2013, 11:55
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Quote:
Why would crews not be able to understand (and manage) the slightly different 'rules of flying' that some sensor failure may cause, such as the loss of protections caused by law reversion?
AZR

Its not the crew, the airlines or the training. All airlines train and all crews are trained - it is the type of training that needs to be reviewed


Quote:
Why would crews not be able to understand (and manage) the slightly different 'rules of flying' that some sensor failure may cause, such as the loss of protections caused by law reversion?
AZR

Its not the crew, the airlines or the training. All airlines train and all crews are trained - it is the type of training that needs to be reviewed
Re quote from Natstrackalpha about the type of training given.
Could not agree more!!!
Forget meaningless time in the sim and trying to land on the piano keys. Fully held off landings seem to be a thing of the past except on 2 airlines mainly crewed by "real pilots". WHY. Try landing an old taildragger without this method and watch the resulting bounce(s)! As a result the U/C gets a pounding. You might float down the R/W a bit but no worry.
In our budget restricted times who wants to shell out on tyres and U/C for clueless but highly educated individuals (poorly trained) who cannot fly.

Seems that all you need for a career is education. WRONG WRONG WRONG. A passion for flying is what you need. Go back to teaching basic piloting skills and not just fly by numbers and the world will be a safer place!!!

Hear endeth the rant
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Old 17th Jun 2013, 12:18
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Originally Posted by BOAC
The pilots need effectively to understand 2/3 'philosophies' - slightly different 'rules of flying' in each law, and to be able to 'switch' seamlessly from one to the other,
I wonder whether it is correct to say that the 'rules of flying' change with the FCS laws. It seems to me they depend on the urgency of the problem.

Situations like low level wind shear and GPWS warning leave no time for thought and just carrying out a drill without hesitation might save the day. In those situations being able to pull without fear of stalling must be an asset.

In AF447 there was no such urgency. The plane would have landed safely in Paris if the pilot had just sat back and 'done nothing'. In that situation there is no need to rely on any protection and the 'rule of flying' in alternate law is no different from that in normal law.

Last edited by HazelNuts39; 17th Jun 2013 at 12:19.
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Old 17th Jun 2013, 12:39
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Natstrackalpha

but, an aircraft encaked in ice with no flying surfaces active having climbed, stalled and then pitched down, increased speed + therefore lift, ocillating from nose hi low airspeed to nose lo hi airspeed, would have had the equal result of `overspeed` and `stall` together on the descending, without any stick held back - as the effect of the stick would have been ineffective anyway.
You haven't the faintest clue what you're on about have you?
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Old 17th Jun 2013, 12:39
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Originally Posted by BOAC View Post
AZR - I agree with NTA on that and have said it before many times.
As I don't understand what NTA point is (perhaps because I'm under the impression he didn't get the facts right), I'll pass to comment on that.

Originally Posted by BOAC View Post
I don't know the answer to your question
OK, thanks.

Originally Posted by BOAC View Post
but in the absence of any logical explanation for AB events such as 447 involving 'failure' of the protection systems, I am asking. A kind of Occam's razor, I suppose?
I'm not aware of a long list of "AB events such as 447 involving 'failure' of the protection systems"...
About the logical explanation, there is one in the final report (as to why 447 crew, and more precisely PF, acted as he did) that looks convincing to me. This could led to technical modifications re: FD availability, but I fail to see how a modification to the protection system would be sensible. On that topic, and the existence of the alternate law (that some people judged misleading and/or dangerous), I just read "QF32" by Cpt de Crespigny and found his view on the matter reassuring.

Finally, if I understand correctly, the "go full back stick and trust protections" is teached *only* for low altitude, terrain avoidance events (e.g. CFIT trajectory, windshears...), *not* as a one-fit-all recipe to get out of trouble.
So AFAIK, HazelNuts39 has it right.
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