Originally Posted by rudderrudderrat
If you are going to be picky, during roll out, you are actually in a sub mode of Direct Law called Ground Mode.
Thank you for being nitpicky for me.
Originally Posted by RR NDB
I donīt like the approach to diagnose UAS by System output.
Neither do I. BEA is also unhappy but it issued no recommendation on fixing it. What you fail to understand is...
Originally Posted by RR NDB
Block garbage to enter System would be better?
...the pressure that hit the total pressure sensor was not the real one due to clogging of the pitot, but such reduced pressure resulted in calculating airspeed of about 52 kt at the minimum and this is valid speed during t/o run or landing roll and cannot be rejected by simple algorithm! This is not readily identifiable to computer as a garbage! It can be identified as such only by someone who has a whole picture of the aeroplane state in his CPU and can recognize that sudden drop from 270 kt to 52 without aeroplane starting to fall or being torn apart in severe turbulence actually means speed display is totally wrong and we call that entity "a pilot". You just can't teach the computer to compare all the parameters and come to intelligent solution, if you try, you can only end up with set of instructions so convoluted its execution will be totally unreliable. Farthest Airbus came is displaying "CHECK GW" message when computer detects discrepancy between input weight, airspeed and AoA - it can not determine which is which so output is made to warn about the most common failure, to input wrong weight into FMGS. A lot of guesswork but it's best that can be done for the time being.
Originally Posted by RR NDB
Sadly, the (non adequately trained) crew of AF447 were:
Question of adequate training is another can of worms. How come other AF crews dealt without much fuss with UAS if AF training is inadequate? It is not just about training, it is also about selection. Starting from the first flight in glider, ending when the logbook is closed for good.
Originally Posted by bubbers44
I don't think the test pilots that approved the 5 degrees nose up and climb power tried it with blocked pitot tubes.
Do you have a slightest idea who writes and approves the procedures?
Originally Posted by bubbers44
The trapped pitot pressure and the decreasing static pressure would cause an indicated airspeed increase and at some point an overspeed warning
So it would! So freaking what? Pilot who would seriously consider acting IAW overspeed warning in UAS situation must be totally "destructured", to use BEA term.
Originally Posted by Lyman
HN.... Why would the boffins select a climb, at all, in the first place?
Panic, caused by sudden realization that something is wrong but one has no clue what it is or what should be done. So doing first thing that crosses his mind and disregarding absolutely every clue it wasn't good idea in the first place.
Originally Posted by RR NDB
R&D must be done to improve current situation.
What situation?
Originally Posted by RR NDB
Why not protect the plane to REC MAX apogee. Hard limit (Airbus SAS approach)
I have read many a misconception about Airbus protection, this one goes into top tier. No altitude protection is offered ever on Airbus as AoA makes it irrelevant. No hard air data based protection is available in alternate laws as there's no sufficient redundancy to guard against the unwarranted activation of the protection.
Originally Posted by TTex600
Poor training. As I've stated more than once on this topic, my training was no better.
How come other 36 crews went through UAS ordeal unscathed? Better training than yours?
Originally Posted by syseng68k
If the systems fail and give no information, then fine
So it is. No electronic part of the system failed in AF447 case. It just wasn't fed the right pressure.
Originally Posted by syseng68k
but to fail and give incorrect information is extremely dangerous
Problem is that many a PPRuNer has noticed it is dangerous only when it resulted in 228 deaths and all of a sudden there are righteous demands, very similar to ones made by certain young F/O
Originally Posted by Ernest K Gann
Captain Hughen, this is all an anachronism. We belong in the modern world and should therefore be secure. Please arrange a remedy for this grievous mistake at once.
At least he was so forthright to humour himself once the fright loosened his grip.
Originally Posted by RR NDB
Simply because Pitotīs may fail SIMULTANEOUSLY
So what? I have flown aeroplane with single pitot and then it got blocked. There's always way out.
Originally Posted by rudderrudderrat
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.
I have to warn everyone that trying to explain some aspect of Airbus FBW while not being versed in basic aerodynamics tends to produce entertaining, if not true or otherwise useful , results. What you are referring to is static stability and that airbus lacks it in normal and alternate law is total non-event.
Originally Posted by rudderrudderrat
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.
What?!? AF447 did regain FL350 by pulling, if only fleetingly as it passed through it on her final descent! Now, if only they pushed...
Originally Posted by TTex600
Bubbers, stop being dismayed about the pilots and start being outraged at the system that trained them and placed them there.
If we assume that Airbus is dangerous by design, shouldn't we be praising the system for always putting the super-pilots in the cockpit that made it home and failing just once? Of course not.
Originally Posted by CONF iture
I don't think they realized they had to deal with an UAS scenario
You are right. How could they realize when they were suddenly faced with 200+ kt drop in IAS?
Originally Posted by CONF iture
But do we know what IAS2 was displaying ... ?
BEA does. 88, 93, 94.
Originally Posted by CONF iture
It is only a temporary fix where the pilot needs to be quicker than the malfunction to badly bite one more time.
Dear CONF iture, by know you should have really known better than assuming I would link to the report without reading it. So: 1. QF72 was single occurrence in 28 million hours of flight 2. temporary fix of switching off the faulty ADIRU was later supplemented by rewriting the FCPC algorithms. I will suggest you should stop burying yourself, just because I know you will not listen to me.