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Old 23rd Nov 2013, 11:10
  #902 (permalink)  
Chris Scott
 
Join Date: Jan 2008
Location: Blighty (Nth. Downs)
Age: 77
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Instrument-Flying Skills

Quote from Clandestino:
"I'll try different approach this time"

If this is a spot-the-difference test, Clandestino, I admit defeat.

As usual, you have quoted snippets of text - sometimes a phrase, rarely more than one sentence - and then dismissed them, in your instinctively adversarial style, without acknowledging their context in the writer's broader argument.

Before I respond to your latest rejection of such a policy, let me reproduce the key points of substance in our discussion about the possible merits of PFs routinely flying jet airliners, in what you neatly describe as friendly skies, with the AP disengaged, and also - where practicable - the A/THR and/or FD.

Clandestino:
"Again: issue with AF447 is not the pilot unable to handfly the aeroplane; it was pilot unable to understand the situation, implication of his actions and pretty precisely handflying just the wrong way, while his assisting pilot was, unfortunately, as lost as him. Nothing of it can be prevented by practising eye-to-hand coordination in friendly skies."

Me:
"I could not disagree more. All that needed to be done in AF447 was to keep the wings level, and MAINTAIN a suitable pitch attitude and thrust for high-altitude cruise. If you are accustomed to monitoring and understanding your a/c in all flight phases, you may learn ball-park figures even without ever disengaging the AP. But there are at least two snags to that as a policy.
"Firstly, you will not learn the very gentleness of any corrections that need to be made on the side-stick if you unexpectedly find yourself without the AP at high altitude. (Rather like driving a car at over 200 kph.) Secondly, human nature means that hands-on practice concentrates the mind in a way that mere observation does not."

The most recent reply from Clandestino:
(1) "Yes but this is all very well when you either know what happened or maintain presence of mind not to do harm when you are not sure what exactly you should be doing."
(2) "You suggest that A330 is sensitive beast that has to be treated gently. I say that it is exaggeration and you can throw her around hamfistedly at cruise altitude, in alternate law for 4 minutes with normal acceleration varying between +1.96 and -0.26G with end result being no worse than just utter mess in cabin and galleys."
(3) "Why are we not discussing some other LOCs like Birgenair? 20 000 hrs could not prepare the skipper for simple recognition that rejecting the takeoff when airspeed is not working is a must or just to crosscheck the three ASIs. Or close call at EHAM where the guy who taught others how to perform V1 cut just couldn't make it properly when it happened for real? That's what AF447 is about: the crew that just couldn't perform when it needed to."

Re (1), you have identified the very point I've been making: the PF needs to know how to avoid doing serious harm to the flight profile, and unnecessarily exploring the limits of the flight envelope.

Re (2), I am saying that, to maintain a safe and sensible flight profile at cruise altitude, you have to handle any large jet with kid gloves. What you may have to do to recover from an unusual attitude is another matter. The fact that airliners are stressed in extremis to about +3.75G and -1.5G is nice to know, but irrelevant to normal operations. The AF447 L.O.C. started with an a/c in normal, stable cruise-flight; albeit in routine, moderate turbulence. Notwithstanding Machinbird's and my own previously-stated reservations about the Airbus FBW downgrade combination of load-factor control in pitch with stick-to-aileron for roll, the only way to develop a scan and stick-dexterity that includes more than one parameter is to practise it regularly.

Regular hand-flying practice reinforces the understanding that in level cruise-flight, regardless of turbulence or windshear, any pitch attitude more than 2 or 3 degrees above or below the norm is unsustainable unless you want to climb or descend. Recovery from any startle factor would be quicker if the PF is confidently familiar with the sort of picture that needs to be maintained or restored on his attitude indicator, and how to achieve it. The same applies to thrust.

Re (3), this discussion clearly reads across to other types, many of which might be more of a handful at the beginning of a similar UAS event than the short-body A330 in Alternate 2B, with its advantage of retaining load-factor control in pitch. The two events you mention were on T/O, presumably involving the requirement for instant decision and rapid action? That did not apply in AF447 - quite the contrary. Excessive reliance on automation may well be eroding the basic instrument-flying skills that my generation, and our forebears, took for granted.

Last edited by Chris Scott; 23rd Nov 2013 at 15:10. Reason: Re-insertion of italics and underscoring. Last para expanded. Title added.
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