Originally Posted by korrol
He’s right - but if you feed pilots air at a cabin altitude of 8000 feet (much lower in oxygen content than air at a real altitude of 8000 feet) then when the chips are down crews will make mistakes - and they did.
Originally Posted by Organfreak
If you said anything like that to a pilot's face in a bar, you'd get your lights punched out.
Originally Posted by CONF iture
Interested in the FULL story, not a partial one, that's it.
Originally Posted by mike-wsm
I am not a pilot and have no qualification beyond a vaguely relevant degree. I never fly.
Originally Posted by mike-wsm
You seem to be falling into the simplistic trap of assuming the elevators and THS were behaving normally. They weren't.
Originally Posted by CONF iture
Autotrim all the way as long as the data are believed to be reliable.
Originally Posted by CONF iture
You did mention a few times AMS, but I am not sure you fully grab the complexity behind the erroneous data and what could be the possible consequences for the Airbus scenario ...
Originally Posted by TTex600
Yes, he will need a lot of force to lower the nose
The way many a PPRuNer glosses over the fact we need to have very powerful THS in modern turbofan transports and that when mistrimmed they can be lethal on any aeroplane, not just on Bus, would have me worried about the knowledge level in today's cockpits if it weren't for the red warning at the bottom of this page.
Originally Posted by CONF iture
To the contrary, if the normal operation of a system is a contributory factor in the crash, the report is the very place where that system has to be analyzed.
Originally Posted by Retired F4
When the aircraft is descending, and you want it to return to the assigned FL, you have to climb. For that you have to raise the nose (SS NU) and maybe you have to add power (TOGA). If 5° pitch is not enough, lets use more........
Originally Posted by TTex600
It seems painfully obvious that the crew handled the UAS event incorrectly and unprofessionally, but we still need to understand why they didn't put "the stick forward until the nose arrives there where you want it".
Originally Posted by Ian W
There is no prestall buffet or normal handling effects if you pull into a hammer-head stall or tail slide this was not far short of that.
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Originally Posted by Clandestino
The way many a PPRuNer glosses over the fact we need to have very powerful THS in modern turbofan transports and that when mistrimmed they can be lethal on any aeroplane, not just on Bus, would have me worried about the knowledge level in today's cockpits if it weren't for the red warning at the bottom of this page.
Originally Posted by Clandestino
They had no clue what to do.
If "they had no clue" is the cause, why haven't we seen a program immediately placed in our training to ensure that we all have a clue? |
Hello,
I am reading the CVR from AF 447 and I wanted to know if anyone knew what the two letters P L meant when the Captain says "t'es P L toi" at 1h56 into the flight. Thanks |
You can download the english version of CVR transcript here:
http://www.bea.aero/docspa/2009/f-cp...nexe.01.en.pdf Hope it's help ! Note: "t'es P L toi" |
Originally Posted by HN39
Without autotrim the FCS will use more elevator to achieve the Nz demand.
No autotrim means no alternate law no more Nz demand. Direct, just direct law, where 20% displacement of the sidestick will produce 6 deg up of elevators. |
No pilot I know couldn't have flown this aircraft or any aircrat by just using pitch and power. How about using what it had when the auto systems cut out. Why do we hire these pilots with minimum time that can't do simple tasks without autopilot? This is the future unfortunately.
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Originally Posted by OK465
The Boeings have an electric stop a degree or so prior to full travel, from which the trim limits can only be reached by rotating the trim wheel manually.
For the A330, according to A33Zab, there is no such electric limitation. After re-reading his post, I can see he had already produced a possible reason for which the THS did not reach the max deflection. But once again, it was the BEA job to develop that stuff ... |
For the A330, according to A33Zab, there is no such electric limitation. After re-reading his post, I can see he had already produced a possible reason for which the THS did not reach the max deflection. But once again, it was the BEA job to develop that stuff ... Nevertheless .. nowhere in the FDR extracts of the BEA is show a trace of this law been triggered ...... I can be wrong ... |
Originally Posted by CONF iture
No autotrim means no alternate law no more Nz demand.
Direct, just direct law, where 20% displacement of the sidestick will produce 6 deg up of elevators. EDIT:: One last try: If the system had been such that in Alt2B from the onset of stall warning the THS setting had been limited between setting at stall warning onset and 2° nose down (i.e. no further uptrim would be applied), but otherwise as is, i.e. Nz law without high-AoA protections, then the elevator trace on FDR would have been as shown by the purple line on the graph up to the point where the elevator reaches 30° at 02:11:41 (101 seconds after 2h10). Up to that point the airplane's trajectory and the stickforce felt by the PF would have been identical to those in the accident. |
It is just comforting to know they might be there if the **** hits the fan. what I meant is that in Alternate Law you are in any case better off than in a conventional plane, as even in the lowest protected level it still offers certain protection. |
The longer the flight, the greater the accident rate
EXENG AF337 had been in the air for over four hours.
The longer the flight at altitudes like 35,000 feet, (at a cabin altitude of 8000 feet) the greater the likelihood that pilots will screw up - see J H Goode (Journal of Safety Research "Are pilots at risk of accidents due to fatigue?" Issue 34: Pages 309–313). The pilots may feel fine - but they're not. It's not their fault. They haven't got enough oxygen in their bloodstreams. Their problem-solving capacity is degraded. Not a lot, but enough to make a difference in a complicated emergency. |
Korrol
Obviously you wrote your post at the incapacitating altitude. AF337??? |
Well, the 337 is a twin. And also has to do with 02.
All things considered, O2 is of course a factor. Pilots get used to it, and it will not likely change. Saying it is no factor is simply simplistic. |
Originally Posted by HN39
If the system had been such that in Alt2B from the onset of stall warning the THS setting had been limited between setting at stall warning onset and 2° nose down (i.e. no further uptrim would be applied), but otherwise as is, i.e. Nz law without high-AoA protections, then the elevator trace on FDR would have been as shown by the purple line on the graph up to the point where the elevator reaches 30° at 02:11:41 (101 seconds after 2h10). Up to that point the airplane's trajectory and the stickforce felt by the PF would have been identical to those in the accident.
A simulator experiment would clearly point the difference. Trimming in a stall is an unknown procedure. It is dangerous stuff. We need to ask Airbus why they think differently. As the BEA avoids asking the tough questions, we need to do it. |
Originally Posted by korrol
flight at altitudes like 35,000 feet, (at a cabin altitude of 8000 feet)
If the premise your conclusion is based on is wrong, and you know that it is wrong, what does that say about your conclusion or you? |
Originally Posted by CONF iture
You simply cannot obtain a similar trajectory with an identical stickforce with 2 scenarios as different as one with a THS set at 3 deg and another one with a THS moving from 3 to 13 deg.
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Originally Posted by CONF iture
(Post 7364726)
Trimming in a stall is an unknown procedure. It is dangerous stuff.
We need to ask Airbus why they think differently. Limiting the trim movement under stall conditions would be simplicity itself in terms of implementation - but the secondary implications (of which there are several) need to be thought through. It's not a "tough question" - not even every contributor on this thread believes it's a *relevant* question. |
Originally Posted by HN39
What a strange statement!
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HN39:
If I may make an input regarding CONF's statement... The manual (hand flown) stall QTG's for the simulator are specified to be done in Direct Law with a specific stop manual trim speed. As you decelerate below this speed, without benefit of trim, SS movements tend to be exaggerated to some extent in both directions to maintain a stable flightpath, with varying levels of spring force to deal with. If the entry is done in Alternate Law, as the rate of airspeed decay progressively increases with the drag buildup, the autotrim input essentially outpaces any necessary SS commands and allows a more 'relaxed' SS input, with less awareness of any spring force. I think this what he is getting at, but I could be wrong, and don't want to speak for him. (CONF: Thanks for the reference to the A33Zab post) |
Originally Posted by Dozy
they simply never countenanced the idea that a pilot would pull into a stall, keep pulling through the stall warning and pull *again* once the stall was established.
What a strange statement coming from you ! Dozy, you keep coming back on how crews have been pulling back on controls all the way during stalls, but Airbus 'simply never countenanced the idea that a pilot would pull into a stall, keep pulling through the stall warning and pull *again* once the stall was established'. So you know about it but Airbus don't ... Give them a call. |
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