AF 447 Thread No. 11
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@Owain
does anyone know what make/model AoA probes are used on the Boeing fleet and Airbus fleet?
Airbus - Thales[Sextant] C16291xx or Goodrich[Rosemount] 861ED (Eddy Current Dampened)
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Interesting Take
Comment by Dan Dair:
NTSB to hold Asiana crash hearings on automation issues | Plane Talking
NTSB to hold Asiana crash hearings on automation issues | Plane Talking
Last edited by Winnerhofer; 26th Oct 2013 at 21:43.
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My neighbor Airbus captain swears their procedure with loss of IAS is max climb power and 5 degrees nose up and laughed because I have 8 jet type ratings and have never been taught that. I said 5 degrees nose up at 35,000 ft means you will eventually stall and go through the altitudes above you belonging to other flights. He says I wouldn't be following the Airbus checklist and laughed some more. With a good altimiter do all Airbus pilots fly like that? We were taught to hold last attitude and power and use the UAS checklist in all 8 jets I was a captain in. With a good altimiter with AP disconnect I wouldn't even call it a big emergency but to fly through unauthorized altitudes would be. This is at least Spirit Airlines procedure.
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mm43 was the first
@Winnerhofer
Best wishes to these NTSB Hearings.
not sure that we must understand "vitesse de fou" as "Overspeed" it could be "too low speed" (already discussed).
Originally Posted by mm43 @ Asiana crash Investigation 25th Oct 2013, 19:42 #116 (permalink)
NTSB Announces Investigative Hearings
Press Release October 22, 2013
Press Release October 22, 2013
Originally Posted by Winnerhofer
"...on a une vitesse de fou.." when he should have said "...on est en survitesse..." (IAS Overspeed).
Last edited by roulishollandais; 26th Oct 2013 at 23:23.
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bubbers44
Is your neighbour fond of wearing hats? Because he certainly is talking through it. You better find someone else to discuss aviation matters. Airbus procedure for UAS is in principle same like in any aircraft. Disconnect automatics fly pitch and thrust and follow the written procedure. On the plus side aircraft still auto trims and maintains wings level/bank so it is always stable. The way 447 pilot reacted was the only way to crash it.
Is your neighbour fond of wearing hats? Because he certainly is talking through it. You better find someone else to discuss aviation matters. Airbus procedure for UAS is in principle same like in any aircraft. Disconnect automatics fly pitch and thrust and follow the written procedure. On the plus side aircraft still auto trims and maintains wings level/bank so it is always stable. The way 447 pilot reacted was the only way to crash it.
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@A33Zab
Thank you for that information; I suspected something along those lines.
Left me wondering if fluid damping, which is proportional to velocity squared, is more effective than eddy current damping (proportional to velocity) in this particular application
Boeing - Goodrich[Rosemount] 861 series (fluid dampened)
Airbus - Thales[Sextant] C16291xx or Goodrich[Rosemount] 861ED (Eddy Current Dampened)
Airbus - Thales[Sextant] C16291xx or Goodrich[Rosemount] 861ED (Eddy Current Dampened)
Left me wondering if fluid damping, which is proportional to velocity squared, is more effective than eddy current damping (proportional to velocity) in this particular application
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Originally Posted by bubbers44
My neighbor Airbus captain swears their procedure with loss of IAS is max climb power and 5 degrees nose up and laughed because I have 8 jet type ratings and have never been taught that. I said 5 degrees nose up at 35,000 ft means you will eventually stall and go through the altitudes above you belonging to other flights. He says I wouldn't be following the Airbus checklist and laughed some more. With a good altimiter do all Airbus pilots fly like that? We were taught to hold last attitude and power and use the UAS checklist in all 8 jets I was a captain in. With a good altimiter with AP disconnect I wouldn't even call it a big emergency but to fly through unauthorized altitudes would be. This is at least Spirit Airlines procedure.
The Spirit COM says the same as the Airbus COM.
I'll paraphrase: If safety of flight is affected..... turn off AP/FD/AT, adjust pitch and power as necessary to reach acceleration alt, gear up, flaps leave at existing position, when at safe circuit alt level off and troubleshoot.
Tables are then provided to supply pitch and power settings for various weights/alts/configurations.
Nowhere do I see a combination of "max climb" power and 5deg nose up.
FWIW, the initial settings offered for cruise flight are 3 deg nose up and 80% N1
Note: Spirit (NK) flies A319/320/321. The pitch/power are for 319.
Last edited by TTex600; 27th Oct 2013 at 07:31. Reason: Add 320 note
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extra text
Villas,
With UAS, the aircraft was in ALT LAW.
Please explain why you think the aircraft was able to maintain wings level/bank.
What is the advantage of auto-trim of the stabiliser during UAS? Surely you would want to maintain the last trimmed AoA before the event?
On the plus side aircraft still auto trims and maintains wings level/bank so it is always stable.
Please explain why you think the aircraft was able to maintain wings level/bank.
What is the advantage of auto-trim of the stabiliser during UAS? Surely you would want to maintain the last trimmed AoA before the event?
Last edited by rudderrudderrat; 27th Oct 2013 at 09:17.
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RRR
In DSC-20-20-20 P 5/8 all it says is
BANK ANGLE PROTECTION
Not provided.
and in PRO-SUP 27-30 P 4/6 it says
Bank stability and protections are no longer active and the flight crew should take care to stay within normal limits.
The protection part is clear but what do you make out of the bank stability? If you bank more than 33 degrees it won't return to 33. But if your bank is within 33 degrees and zero will it hold or not. If not then it is laterally unstable. What's your take?
In DSC-20-20-20 P 5/8 all it says is
BANK ANGLE PROTECTION
Not provided.
and in PRO-SUP 27-30 P 4/6 it says
Bank stability and protections are no longer active and the flight crew should take care to stay within normal limits.
The protection part is clear but what do you make out of the bank stability? If you bank more than 33 degrees it won't return to 33. But if your bank is within 33 degrees and zero will it hold or not. If not then it is laterally unstable. What's your take?
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RRR
Auto trim is not trimming for speed bu the flight path. Provided you hold the correct pitch it will trim that. Isn't that the difference between Alternate and direct law? Makes things easier.
Auto trim is not trimming for speed bu the flight path. Provided you hold the correct pitch it will trim that. Isn't that the difference between Alternate and direct law? Makes things easier.
Last edited by vilas; 27th Oct 2013 at 12:29.
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Trim
Airbus is vector-stable.
Boeing is speed-stable.
This is why Boeing AutoTrims for speed and not for pitch.
Related links:
http://www.pprune.org/tech-log/50332...aws-1-2-a.html
http://www.pprune.org/tech-log/50181...30-flawed.html
http://www.pprune.org/tech-log/50372...oa-probes.html
Boeing is speed-stable.
This is why Boeing AutoTrims for speed and not for pitch.
Related links:
http://www.pprune.org/tech-log/50332...aws-1-2-a.html
http://www.pprune.org/tech-log/50181...30-flawed.html
http://www.pprune.org/tech-log/50372...oa-probes.html
Last edited by Winnerhofer; 27th Oct 2013 at 10:32.
@vilas,
the mode was Alt2B. In this mode the roll channel is not stabilized like in Normal Law or in Alt1, no bank stability except the natural one is available then.
Therefore the reaction of the aircraft after AP disconnect was:
We have been through this before.
the mode was Alt2B. In this mode the roll channel is not stabilized like in Normal Law or in Alt1, no bank stability except the natural one is available then.
Therefore the reaction of the aircraft after AP disconnect was:
Final report page 172
2.1.2.3 Control of the flight path
When the autopilot disconnected, the roll angle increased in two seconds from 0 to +8.4 degrees without any inputs on the sidesticks. The PF was immediately absorbed by dealing with roll, whose.........
2.1.2.3 Control of the flight path
When the autopilot disconnected, the roll angle increased in two seconds from 0 to +8.4 degrees without any inputs on the sidesticks. The PF was immediately absorbed by dealing with roll, whose.........
We have been through this before.
Last edited by RetiredF4; 27th Oct 2013 at 13:49.
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vilas;
Re, "Thanks. I will look for older posts. ",
The following link to a PPRuNe search engine may be of assistance: AF447 Search Index for PPRuNe Forums
The UAS discussion is interesting.
A change in pitch attitude at cruise altitude destabilizes a stable airplane and so should be a consideration before executing the UAS memorized items which require an initial pitch change where none is required.
Establishing a 5° pitch would mean an increase of about 2.5° to the cruise pitch attitude...not destabilizing right away but would be if held too long.
The remarks in FCTMs, (Flight Crew Training Manual(s)) indicate that:
The subject is discussed widely on many of the previous 10 threads. Some further discussion is available here, and on this thread, here.
Re, "Thanks. I will look for older posts. ",
The following link to a PPRuNe search engine may be of assistance: AF447 Search Index for PPRuNe Forums
The UAS discussion is interesting.
A change in pitch attitude at cruise altitude destabilizes a stable airplane and so should be a consideration before executing the UAS memorized items which require an initial pitch change where none is required.
Establishing a 5° pitch would mean an increase of about 2.5° to the cruise pitch attitude...not destabilizing right away but would be if held too long.
The remarks in FCTMs, (Flight Crew Training Manual(s)) indicate that:
ADR CHECK PROC / UNRELIABLE SPEED INDICATION QRH PROCEDURE
The flight crew may enter this procedure, either upon ECAM request (ADR DISAGREE or ANTI-ICE PITOT caution), or because he suspects an erroneous indication, without any ECAM warning.
When to Apply this procedure
1, 2, 3, etc;
5. Rely on the stall warning that could be triggered in alternate or direct law. It is not affected by unreliable speeds, because it is based on angle of attack.
6, 7, etc
If the safe conduct of the flight is affected, the flight crew applies the memory items. They allow "safe flight conditions" to be rapidly established in all flight phases (takeoff, climb, cruise) and aircraft configurations (weight and slats/flaps).The memory items apply more particularly when a failure appears just after takeoff. Once the target pitch attitude and thrust values have been stabilized, as soon as above safe altitude, the flight crew will enter the 2nd part of the QRH procedure, to level off the aircraft and perform trouble shooting. This should not be delayed, since using the memory item parameters for a prolonged period may lead to speed limit exceedance.
(Note: SOPs published, early 2007)
The flight crew may enter this procedure, either upon ECAM request (ADR DISAGREE or ANTI-ICE PITOT caution), or because he suspects an erroneous indication, without any ECAM warning.
When to Apply this procedure
1, 2, 3, etc;
5. Rely on the stall warning that could be triggered in alternate or direct law. It is not affected by unreliable speeds, because it is based on angle of attack.
6, 7, etc
If the safe conduct of the flight is affected, the flight crew applies the memory items. They allow "safe flight conditions" to be rapidly established in all flight phases (takeoff, climb, cruise) and aircraft configurations (weight and slats/flaps).The memory items apply more particularly when a failure appears just after takeoff. Once the target pitch attitude and thrust values have been stabilized, as soon as above safe altitude, the flight crew will enter the 2nd part of the QRH procedure, to level off the aircraft and perform trouble shooting. This should not be delayed, since using the memory item parameters for a prolonged period may lead to speed limit exceedance.
(Note: SOPs published, early 2007)
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Apollo 13 astronaut: pilots lack basic hand-flying skills
Capt Jim Lovell said it was basic flying skills that allowed him and his crew to navigate their way back to Earth after an oxygen tank exploded during their voyage to the moon in 1970.
Recent air disasters such as Air France flight 447, lost over the Atlantic in 2009, and the Asiana Airlines plane which crash landed in San Francisco this summer indicate that pilots have become too reliant on autopilot, he added.
Recent air disasters such as Air France flight 447, lost over the Atlantic in 2009, and the Asiana Airlines plane which crash landed in San Francisco this summer indicate that pilots have become too reliant on autopilot, he added.
Avoid imitations
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He might have been better saying "some airline pilots".
Not all pilots even have an autopilot in the aircraft.
Not all pilots even have an autopilot in the aircraft.
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The 73NG spends most of the cruise phase with about 3 degrees nose up pitch, nearly 90% N1 on the thrust and stab about 6.0.
All #s easily divisible by 3, a frequent and useful number in aircraft, so if I was ever to end up in AF447s predicament I would set these and keep the blue side up and the brown side down til we fell out of the other side of ITCZ or whatever was giving us grief, then reassemble the flight profile and if appropriate, carry on.
Thanks to this accident & forum for causing me to note these NORMAL settings, so's I have an instantaneous datum to set whilst waiting for my oppo to come back from the bog, when we can then start chasing QRH and DODARing and all the follow-up housekeeping items.
Has anyone else quietly looked at their own 'frames settings since and filed it away for ready reference til there's time to perform the UAS drill?
This is in addition to the normal pitch 'n power settings we hopefully know for other flight phases.
All #s easily divisible by 3, a frequent and useful number in aircraft, so if I was ever to end up in AF447s predicament I would set these and keep the blue side up and the brown side down til we fell out of the other side of ITCZ or whatever was giving us grief, then reassemble the flight profile and if appropriate, carry on.
Thanks to this accident & forum for causing me to note these NORMAL settings, so's I have an instantaneous datum to set whilst waiting for my oppo to come back from the bog, when we can then start chasing QRH and DODARing and all the follow-up housekeeping items.
Has anyone else quietly looked at their own 'frames settings since and filed it away for ready reference til there's time to perform the UAS drill?
This is in addition to the normal pitch 'n power settings we hopefully know for other flight phases.
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JS, thanks for the loss of IAS checklist not being applicable in cruise but my Airbus captain neighbor still doesn't believe it so the debate goes on. Actually it is good because when he comes over he drinks all of our alcohol so him calling me stupid and and idiot saves me lots of money because we disagree a lot. He usually stays mad for a month. Thanks.