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Old 14th Oct 2016, 10:31   #1181 (permalink)
 
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Would this A330 have been able to roll out of the stall to gain some pitch authority later on as the stall was broken?
If so, and considering SA parameters would be improved in daylight, you'll understand my earlier thinking about what effect night had on this scenario. The high nose attitude, i.e. seeing only sky, IMHO might have helped them understand where they were and what they were doing and thus hinted to stop doing it. Ultimately they might have sensed what to do and how to do it and appreciated they had lots of air underneath them and where the horizon was. In the dark, and a panic sets in and takes over, that loss if visual sense surely did not help any.
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Old 14th Oct 2016, 12:48   #1182 (permalink)
 
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What was the THS showing on Uplinker's demonstration on #1119 as frozen ? AF447 was fully NOSE UP, if I remember correctly.
WHO DOES EVER LOOK?

Could somebody say what the NORMAL range of THS could be expected in CRUISING flight ?
( I would not look normally,either, but I am not AB rated.)

As a trainee I had tried using the Trim wheel on an AS Oxford in 1949 at Hamble to round out... It looked professional, I thought.

My Instructor said " Don't do that... Think about a possible Overshoot. " I never did THAT , showing off again.)

Last edited by Linktrained; 14th Oct 2016 at 12:55. Reason: bits
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Old 14th Oct 2016, 13:32   #1183 (permalink)
 
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How will Daylight make any difference if the visibility is poor? Isn't instrument flying done with reference to attitude? A pilot at high altititude has to have some idea of attitude even if you want to climb.Airbus supposed to have good roll control in stall.
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Old 14th Oct 2016, 15:33   #1184 (permalink)
 
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RAT 5,
Quote:
Would this A330 have been able to roll out of the stall to gain some pitch authority later on as the stall was broken?
Going back to AF 447 Thread No. 9, here is some information of one of the two sim exercises that indicated recovery from a full stall could be possible. The comments on the sim exercise below was done by PJ2, a former A-330 captain, now retired.
Quote:
In the sim exercises, the SS was held full forward to achieve about 10degND pitch. The THS followed up on the command and returned to about a -3deg position. Recovery took about 40 seconds. (Note for others: I realize the sim cannot replicate full-stall conditions due absence of data but neither is the behaviour completely irrelevant).

For the exercise anyway and from my pov, there was sufficient elevator available to get the nose down, and the job was made easier by the THS following up the SS ND commands.
There was another sim trial which gave basically the same result and there was a analysis of data the indicated AF 447 could have been recovered by pushing the SS forward and holding it.

As I recall from a stall at 35,000 Ft., recovery was achieved around 20-25 thousand feet. As I recall, there was caution at the recovery point to take care in introducing nose up for fear of creating another stall.
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Old 14th Oct 2016, 16:54   #1185 (permalink)
 
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Further to #1182

IF THS is usually " 5 units Plus or Minus 2 units" .... But is seen to be outside this range ... THAT might make a Pilot suspect that something might be WRONG.


There were THREE pilots on AF447. ( Just ONE on the Sim )


" Our HEARING is the first SENSE to be shut down." #1136
I am not sure that this was known when a Potential Chief Pilot for a new Airline was being checked by our Fleet Manager was FAILED for failing to " Stop for an Engine Fire before V1... "

He was sent home.

( Some years later our Fleet Manager asked me if I felt that he had done the right thing.. With the THEN knowledge.. I felt that he had done the right thing. The FIRE Warning Had been close to the Potential Chief Pilot's left ear... And he had done NOTHING.
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Old 15th Oct 2016, 09:26   #1186 (permalink)
 
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Quote from Linktrained:
"IF THS is usually " 5 units Plus or Minus 2 units" .... But is seen to be outside this range ... THAT might make a Pilot suspect that something might be WRONG. "

Not having flown the A330, I stand to be corrected, but I think 2 deg NU plus-or-minus 2 deg might be nearer the norm in high altitude cruise. It varies, as you would appreciate, with CG position, weight and speed.

In AF447, the PF's inputs on the sidestick resulted in the THS correctly auto-trimming ultimately to its nose-up trim-stop of about 13 deg NU. This could have been reversed, of course, by sustained forward command on the sidestick, as PJ2 demonstrated in the simulator (see quote by Turbine D, above).
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Old 15th Oct 2016, 14:44   #1187 (permalink)
 
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After having held the stick back till THS went full up, the recovery is faster if you manually trim forward while holding the nose down.
Quote:
Our HEARING is the first SENSE to be shut down."
but the iris opens full wide to gather maximum light to help you see provided you look at the PFD to see the attitude and not speed which was unreliable anyway. This is a case as I quoted the NTSB guy someone doing too much too soon followed by too little too late.
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Old 15th Oct 2016, 15:02   #1188 (permalink)
 
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Chris,
Thanks,

I used "units" because I too have not flown the A330. Your "2 deg NU plus-or-minus 2 deg " looks like what I was trying to say.

But to fly very much out of this kind of range without good reason - and apparently without noticing or comment...

My fairly ordinary car has an oil pressure gauge which is backed up with an oil-pressure warning light. This would come on if the oil pressure fell below a certain figure. The system was installed when the car was made.

(As a York F/O I could notice an increase of 1 or 2 Kts when the Captain went back to the rear toilet, when hand flying with A/P U/S-, Captains weighed more as a percentage of A.U.W., then .)
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Old 15th Oct 2016, 15:05   #1189 (permalink)
 
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How will Daylight make any difference if the visibility is poor? Isn't instrument flying done with reference to attitude?
but the iris opens full wide to gather maximum light to help you see provided you look at the PFD to see the attitude

In daylight, if you look out the side window (ok you can't see the wing tip) as you pull up for the loop you will have no doubt what your attitude is. However, here was a case of not keeping the G on over the top.
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Old 16th Oct 2016, 16:50   #1190 (permalink)
 
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Uplinker
AF447 has run the whole gamut but I am not sure whether this article on use of simulators from airbus FAST publication of 24May1999 was discussed. It raises a question mark on credibility of simulator behaviour outside the flight envelope. Produced below:


USE OF SIMULATORS


We manufacturers were very concerned over the types of manoeuvres being flown in simulators and the conclusions that were being drawn from them. Simulators, like any computer system, are only as good as the data that goes into them. That means the data package that is given to the simulator manufacturer. And we test pilots do not deliberately lose control of our aircraft just to get data for the simulator. And even when that happens, one isolated incident does not provide much information because of the very complicated equations that govern dynamic manoeuvres involving non-linear aerodynamics and inertia effects.
The complete data package includes a part that is drawn from actual flight tests, a part that uses wind tunnel data, and the rest which is pure extrapolation. It should be obvious that firm conclusions about aircraft behaviour can only be drawn from the parts of the flight envelope that are based on hard data. This in fact means being not far from the centre of the flight envelope; the part that is used in normal service. It does not cover the edges of the envelope. I should also add that most of the data actually collected in flight is from quasi-static manoeuvres. Thus, dynamic manoeuvring is not very well represented. In fact, a typical data package has flight test data for the areas described in Table 1. In other words, you have reasonable cover up to quite high sideslips and quite high angles of attack (AOA), but not at the same time. Furthermore, the matching between aircraft stalling tests and the simulator concentrates mainly on the longitudinal axis. This means that the simulator model is able to correctly reproducethe stalling speeds and the pitching behaviour, but fidelity is not ensured for rolling efficiency based on a simplified model of wind tunnel data) or for possible asymmetric stalling of the wings. Also, the range for one engine inoperative is much less than the range for all engines operating and linear interpolation is assumed between low and high Mach numbers.Wind tunnel data goes further. For example,a typical data package would cover the areas described in table 2. In fact, this is a perfectly adequate coverage to conductall normal training needs. But it is insufficient to evaluate recovery techniques from loss of control incidents. Where as, the training managers were all in the habit of demonstrating the handling characteristics beyond the stall; often telling their trainees that the rudder is far more effective than aileron and induces less drag and has no vices! In short, they were developing handling techniques from simulators that were outside their guaranteed domain. Simulators can be used for upset training, but the training should be confined to the normal flight envelope. For example, training should stop at the stall warning.They are “ virtual” aircraft and they should not be used to develop techniques at the edges of the flight envelope. This is work for test pilots and flight test engineers using their knowledge gained from flight testing the “ real”aircraft

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Old 16th Oct 2016, 18:39   #1191 (permalink)
 
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Vilas thanks for that. As I said AF447's nose did not dip/drop.
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Old 19th Oct 2016, 08:27   #1192 (permalink)
 
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Thank you vilas.
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Old 19th Oct 2016, 10:00   #1193 (permalink)
 
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Also those that have hand flown a 2000 ft climb in a real A330 at high altitude 38to40g. & have done the same in the sim; will appreciate the " vast " difference in how the aircraft handles. Now think what the real aircraft handles like in alternate law at high altitude. Well their are not many pilots who know/ experienced that.
Whatever hindsight says the pilots of A447 were in unknown/untrained territory so some sympathy should be awarded.
Those that say they could have done better, maybe should think about their experience of handling Airbus FBW aircraft in alternate law at high altitude.
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Old 19th Oct 2016, 10:52   #1194 (permalink)
 
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My thoughts exactly, Icepack.

Also: these days in the SIM we are told about a particular thing, maybe given a presentation in the briefing room, then we go straight into the SIM and do it. So we know what is going to happen, we are expecting it, and unsurprisingly we know how to deal with it.

Things such as this need to be sprung on us without prior warning to ensure we are robust enough - and if not, then more training is required*. If we have just been told about something 30 minutes ago, 99% of pilots will be able to recognise it and recover correctly !

I would also like to see in the SIM the full lead-up to and all the warnings and mode reversions etc. of recent accidents and every OEB that is published. Words on a page are all very well, but until you actually see what they saw and experience what they experienced, it is not easy to fully appreciate and assimilate all the issues.


*Yeah, I know: it costs too much money blah blah.
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Old 19th Oct 2016, 16:00   #1195 (permalink)
 
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Also those that have hand flown a 2000 ft climb in a real A330 at high altitude 38to40g. & have done the same in the sim; will appreciate the " vast " difference in how the aircraft handles.

I wonder how many pilots of any modern jet a/c have hand flown their steed at high FL's. During LT I always used to introduce the student to such a heresy. You could sense the pitch response in <100' deviation to avoid apoplectic ATC queries, and somewhere en-route, if you're lucky these days, there might be a track change sufficient to feel the roll sensitivity.
If cruising below RVSM it was also interesting, and if ever you found an opportunity above, it was more so.
Most enjoyed the experienced; some were nervous as a turnip on Halloween and even declined. To my knowledge it is not a standard LT item. However, when asked why do it; I replied that a u/s AP was not a reason to ground the a/c. It would still fly and be controllable. An old friend of mine, TRE A340 Air Mauritius, had to do just that after airborne from LHR all the way south. Shock horror HAL had gone AWOL at 1000'. The pilots swapped PF roles at sensible intervals. Wide eyed amazement by the F/O and all on the ground at home base.
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Old 20th Oct 2016, 19:19   #1196 (permalink)
 
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Quote from RAT5:
"I wonder how many pilots of any modern jet a/c have hand flown their steed at high FL's. During LT I always used to introduce the student to such a heresy. You could sense the pitch response in <100' deviation to avoid apoplectic ATC queries, and somewhere en-route, if you're lucky these days, there might be a track change sufficient to feel the roll sensitivity.
If cruising below RVSM it was also interesting, and if ever you found an opportunity above, it was more so.
Most enjoyed the experienced; some were nervous as a turnip on Halloween and even declined. To my knowledge it is not a standard LT item. However, when asked why do it; I replied that a u/s AP was not a reason to ground the a/c. It would still fly and be controllable."


As you say, this seems to be regarded as a heresy today, yet the lack of a serviceable AP is not necessarily a no-go item (admittedly, I don't have an A330 MMEL to hand). Yet an A330's flying characteristics at M0.82 at FL350, for example, are not much different from first or second-generation jets at the same speed and altitude. The difference is that C* presumably makes pitch control much easier on the A330 than on traditional types, as it certainly does on the A320.

On one flight in the 1970s when I was on the B707-320, the single AP went u/s in the climb out of Caracas for London. (No A/THR on that type, although the F/E would assist.) The skipper and I shared the handling, including step-climbs eventually to FL410. No RVSM in those days, admittedly, but handling to within plus-or-minus 100 ft was quite feasible for about 20 minutes at a time.

It's worrying that handling skills and practice have allegedly lapsed to a point where most pilots regard cruise flight as being beyond their remit except, of course, in a very-rare failure case. As I wrote in post #1146:
"...Although it would have to be in Normal Law, regular practice of handling cruise flight, including step climbs and descents, at least puts pilots in a stronger position to handle abnormalities such as befell AF447. Easy to read that a pitch change of one degree represents a VS change of about 800 ft/min at Mach 0.8; quite another to be in regular practice at doing it. Thus, the management of pitch & thrust become second nature, instrument scan is improved, and the panic factor in failure situations significantly reduced."

I could have added that using manual thrust at the same time would be useful training for the UAS case - in terms of both throttle handling and observing power settings.
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Old 20th Oct 2016, 19:56   #1197 (permalink)
 
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I remember in my naive enthusiastic sponge sucking days as a RHS HS-125 flying the tiny jet from Stavanger- LHR FL410 manually the whole way, at night, while the boss did business down the back until TOD. No big deal, and a great learning period.
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Old 13th Dec 2016, 15:55   #1198 (permalink)
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https://www.youtube.com/watch?v=WqxzpGJbzmI
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Old 13th Dec 2016, 22:04   #1199 (permalink)
 
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BEA

From what I recall of the CVR, the narrator must be mistaken, when he says: "Here, the Captain declares, 'STALL', descend...." At 2:13 of the CVR?

I remember there is no mention of Stall in the CVR?
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Old 16th Dec 2016, 17:09   #1200 (permalink)
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Well spotted!
Shame that the narrator got that one wrong.
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