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-   -   AF 447 Thread No. 9 (https://www.pprune.org/tech-log/489774-af-447-thread-no-9-a.html)

Lyman 5th Aug 2012 03:56

It would be important to assess different characteristics airframe to airframe, crew response, etc. do you know if any in-depth analysis is ongoing?

Hunter58 5th Aug 2012 08:57

Machinbird

For most operators UAS ist NOT a reportable item and therefore the NTSB would not know about it either. To write it in plain languague. UAS is existing in aviation since the introduction of speed measurement and has not been a real problem since the effects were (and I assume still are) part of basic training, starting very early in the training of the most basic aircraft. It is not over 50 cases, it is thousands of cases. But they were not reported since they are a non-event.

barrymah 5th Aug 2012 10:11

I wonder if the Colonel Xavier MULOT is the same one who is on now on the staff of the French Embassy in Qatar? or is it a coincidence?? I had a google but didn't find any specific on his 'demission' - different from limoge (fired)....(accents missing in the french words).

More conspiracy stuff??

rudderrudderrat 5th Aug 2012 10:40


It is not over 50 cases, it is thousands of cases. But they were not reported since they are a non-event.
I would agree if the aircraft has natural positive dynamic stability, then it is a non event.
If left alone after a disturbance, it will naturally seek its trimmed angle of attack.

For an aircraft with neutral static stability, then it is a problem.
Any deviation must be recognised and corrected early. Once AF447 had deviated by that much Altitude, it didn't matter how hard they pulled trying to regain FL 350 - it would't work.

Edit: Typo: changed dynamic to static.
Thanks to Clandestino for pointing it out so tactfully.

jcjeant 5th Aug 2012 11:58


I wonder if the Colonel Xavier MULOT is the same one who is on now on the staff of the French Embassy in Qatar? or is it a coincidence?? I had a google but didn't find any specific on his 'demission' - different from limoge (fired)....(accents missing in the french words).
It has certainly been promoted .. this is normal .. even the U.S. that also happens ... the morons responsible for security the 9-11 were promoted to a higher level :)
More conspiracy stuff?? :8

Turbine D 5th Aug 2012 16:00


Originally posted by RR_NDB - On Fukushima / GE:
Highly debatable - not appropriate for discussion here - go to JB - Japan Earthquake and Tsunami where this was discussed in detail.

Originally posted by alph2z - This could be useful IAS data that could be made available to the Flight management computers and pilots.
Since the engines seem to have performed flawlessly at TOGA, high altitude, and at high AOA I would presume some useful data for the computers to help with valid data correlation.
Very, very good observation, I think this will/is being looked at, particularly the valid data correlation.

Originally posted by Lyman - Different airstream, dependent on demand, not ambient velocity.
Nonsense, see above plus I suggested this to you a few threads ago.

Originally posted by Lyman - Do you not mean "Detent"? Indent is new to me.
Thanks for spotting my error, got my "I" mixed up with my "D" on the keyboard.

Originally posted by Lyman - Each flight is separate from the next, do not get too comfortable with "millions of flight hours".......how many of those flights had an abnormal? That makes the odds all of a sudden a little shorter.
However you want to look at it, there are both millions of flights as well as flight hours. The occurrence of UAS is a small number from which all crews managed to recover and fly on, except for one.

Originally posted by Lyman - I have seven miles below me, and as far as 447 was concerned, they had only a half mile UP...push everything to max and what, then worry immediately when to stop? Why not consider UAS an impromptu TOD? Stabilize in a shallow descent, and start trouble shooting... ICE might be a wild card as to AoA vanes, but in truth, don't you think a shallow descent at idle might work, if not, then 60? If fuel is an issue, you may not be ETOPS compliant in the first place, and .....? Now I know you will say, but they need only five degrees, and 100 percent, or a bit less, but isn't it more judicious to demand less of the airframe and engines whilst troubleshooting? Less chance of the "crazy speed?" if one can find five, can one find 0? It brackets cruise AoA?
If a crew can't stabilize at 2.5-5º nose up how can they better stabilize in a "shallow descent? "crazy speed" was a result of pitot icing so how can there be less chance of this going down? And, how does going down result in less stress on the airframe or engines verses going up, particularly if sidestick management is heavy handed? explain?

Originally posted by Lyman - Wait, do I have a choice? Cost, performance, and reliability?
I build airliners, I choose cost, and erm, cost...
Luckily, for all concerned, you don't build airliners.

HazelNuts39 5th Aug 2012 19:22


Originally Posted by alph2z
How many heated pitots are there on the upstream of each engine ? 1 or 2 ?

That question has been asked on an earlier thread. I believe the answer was that the FADEC of the GE engine receives its environmental data from ADIRU 1 & 2.

Note that in the Air Caraibes UAS event the discrepancy between the aircraft pitot pressure and the engine P2 caused the ECAM message "ENG 1(2) EPR MODE FAULT". The GE engine is N1-controlled.

Turbine D 5th Aug 2012 20:32

Hi Hazelnuts39,

Your memory regarding the FADEC & ADIRUs 1 & 2 is correct. The suggestion of somehow using an array of pitot tubes in the engine nacelle as a backup to the normal 3 fuselage mounted pitots would apply to future developed aircraft and engines. I would guess it would depend on the ability to both correlate and then integrate them into the overall aircraft monitoring system. It would require extensive testing to determine if this "backup" system would be operational and not develop icing should the normal pitots fail for openers. I do suspect searching for a solution is being worked in the industry to prevent pitot problems leading to instances of UAS on aircraft being developed or in the conception stage.

gums 5th Aug 2012 21:13

Control/trim law bias for AoA or speed
 
Thanks Turbine for the 777 poop.

Seems Boeing likes a plane that trims for speed/AoA versus one gee corrected for attitude/climb angle. And the pilot has to command a different trim speed/AoA if I read the data correctly. No automatic THS to maintain commanded gee.

Interesting that pulling/pushing the stick ( stick/yoke, what the hell) against the trim setting has increased force. So there is an artificial force feedback, huh?

I was also impressed with a fairly simple reversion sequence when the primary laws go away.

The stall protection implementation also seems very intuitive to pilots that did not grow up learning to "monitor" the Airbus system do its thing. Hmmmmm.....

Again, thanks Turbine.

bubbers44 5th Aug 2012 22:11

A pilot should be able to fly any aircraft without needing training. Yes the training is good to teach the differences but no competent pilot should be required to know how to recognize and recover from a stall. That was taught in the first 5 hours of instruction. It is so basic, lower the nose and regain airspeed. AF had two pilots who couldn't do that. I am sure the captain could have but by the time he entered the cockpit the PF had screwed it up so bad he was even confused.

We need to not let automated airplanes make pilots monitors. They both forgot how to fly watching the magenta line.

TTex600 5th Aug 2012 22:24

Bubbers, stop being dismayed about the pilots and start being outraged at the system that trained them and placed them there.

bubbers44 5th Aug 2012 22:40

TT, I agree with your statement. This wasn't a problem when I started flying. It is now. Competent pilots were the only people hired when I was. Now with automation competent pilots are too expensive so they hire the cheapest pilots out of pilot school they can find. Sad but true.

bubbers44 5th Aug 2012 22:50

Embry Riddle pumps out pilots with no experience as soon as Daddy can pay for it. Now they are qualified for a 24,000 a year job with a mere 200,000 help from Daddy. A friend of mine just funded this exact thing.

Lyman 5th Aug 2012 23:41

TD....

Quote:
Originally posted by Lyman - Different airstream, dependent on demand, not ambient velocity.
"Nonsense, see above plus I suggested this to you a few threads ago."


"The suggestion of somehow using an array of pitot tubes in the engine NACELLE as a backup to the normal 3 fuselage mounted pitots would apply to FUTURE developed aircraft and engines. I would guess it would depend on the ability to both correlate and then integrate them into the overall aircraft monitoring system. It would require extensive testing to determine if this "backup" system would be operational and not develop icing should the normal pitots fail for openers/B]

Are you so eager to utilize the word "nonsense", that you miss the accuracy contained in my post?

By the way, I did not correct your spelling of the word "intent". The word was spelled correctly. I merely asked if you had meant "Detent" instead....

My original comment was based on data you enlarge in your retort to my succinct post. I am full of nonsense, but you think enough of it to widen the prose used to expand on it?

What's up widdat...?

CONF iture 6th Aug 2012 04:26


Originally Posted by Turbine D
I would not think reducing power and going down would be the thing to do as the speed would rapidly increase leading to a speed-speed warning.

It is a safe procedure as long there's nobody below.
It has been done by a few crews.
Idle + pitch on the horizon or slighly below do just fine.
Absolutely no risk of overspeed.
Just like a normal descent from cruise level.


There are times when following directions that, or should be, the basis of the word "Aviate" are really important.
To follow directions or switch to a memory item, you need first to understand what you are facing. For them the first signal was the alarm and the red ecam for AP disconnect - Probably also a sudden drop of indicated altitude - I don't think they realized they had to deal with an UAS scenario - Among the reported events, is it possible no one called for the UAS memory item, and no one deselected the FD ?

When it was getting obvious that UAS events in altitude were adding up, it would have been very wise to simulate such scenario during recurrent training : This, is what you may encounter, there are all the associated ecam and alarms, that's what your PFD may look like : THIS IS WHAT YOU NEED TO DO.

I am a bit disapointed we still have not done it in my outfit

Everything is so much easier when you have been properly demonstrated once.

bubbers44 6th Aug 2012 04:47

Why climb or descend with UAS? Why not stay level, use the altimiter and VSI to maintain altitude? Why bust through everybody elses altitude? I only flew Boeings and MD's but no procedure required changing altitude in cruise because of UAS. Every aircraft has an UAS checklist, get it out and stay level. Just my opinion because I stayed away from the Airbus.

HazelNuts39 6th Aug 2012 07:48


Originally Posted by CONF iture
Probably also a sudden drop of indicated altitude - I don't think they realized they had to deal with an UAS scenario - Among the reported events, is it possible no one called for the UAS memory item, and no one deselected the FD ?

Is it possible that a pilot sees the IAS drop from 274 kt to 52 kt in a matter of seconds, and not consider the IAS to be unreliable?

From the Air Caraibes memo (my translation):

"Phase 4, crew reaction
Starting at 22:22:59 during 1m26s the indications of CAS, Mach and altitude are not reliable. The PF flies manually without FD, without FPV, and without A/THR. In that period the various warnings on ECAM, Master Warning, Master Caution, Cavalry Charge, Single Chime, and STALL are numerous. In this extremely charged context, the crew concentrates thus on the piloting of F-OFDF and the application of the checklist QRH 2.21 UNRELIABLE SPEED INDICATION. (...). "


I am a bit disapointed we still have not done it in my outfit

Everything is so much easier when you have been properly demonstrated once.
Agreed. It is difficult to understand that this is still not being addressed in training.

IcePack 6th Aug 2012 12:38

It is not being addressed in training as their are no algorithm's in the sims for high altitude handling. ( most only up to 14000ft) which risks negative training.

john_tullamarine 6th Aug 2012 12:57

no algorithm's in the sims for high altitude handling

.. a matter of tweaking the box's software.

CONF iture 6th Aug 2012 15:31


Originally Posted by HN39
Is it possible that a pilot sees the IAS drop from 274 kt to 52 kt in a matter of seconds, and not consider the IAS to be unreliable?

But do we know what IAS2 was displaying ... ?

The last time we did practice a scenario of UAS at low level, the initial clue that something was wrong came under the warning : WINDSHEAR WINDSHEAR WINDSHEAR
My airspeed was getting in the red, which made sense to me in case of windshear.
As per SOP my call was "WINDSHEAR TOGA" which implies to follow the FD, not to turn them OFF.
That's only when I heard the instructor word : "eh guys ..." that I took a quick look at the other PFD and could remember that one of the exercises for the day was UAS not WINDSHEAR ... The appropriate call was then only made : "UNRELIABLE SPEED"

This is how things can get confusing sometimes.


Originally Posted by IcePack
It is not being addressed in training as their are no algorithm's in the sims for high altitude handling. ( most only up to 14000ft) which risks negative training.

This is not so much about the handling, but how the avalanche of warnings can just mean that : UAS, and how the energy of the PF should go on maintaining a normal pitch attitude for cruise and the energy of the PNF should go on the monitoring the PF performance. The only actions the PNF could perform would be to kill the FD and set the thrust at a normal thrust setting for cruise.

All the concentration and energy on aviate - This is not necessarily easy as the multiple warnings don't seem to stop.

This could be like suddenly switching from a walk in the park to seat in a formula one at 300 km/h


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