Originally Posted by rudderrudderrat
Please explain why you dismiss, for the 15th time at least, a vertical descent rate of 10,000 ft per minute (about 100 kts) does not qualify as a valid speed for angle of attack vanes.
1. no swiveling pitot probes generally and on 330 in particular 2. trigonometry.
Originally Posted by Gums
The 'bus and my little jet 40 years ago used, and still uses, the "q" for "gains", which limits the rate of control surface movement accordingly.
Well, that's the beauty in simplicity of the Airbus FCS: it doesn't need q. Pilot inputs G demand, elevator moves to meet it (as measured by IRS) and that's all there is to it. No need for taking q from ADC or elevator pitots to adjust stick stiffness, there is just non-adjustable spring. You might have all air data shot up and still have G command and protection - that's what is meant by obscure (to some) term "Alternate law". Of course, simpler means cheaper but also means there are far less components to break down.
Much ado has been made around here about complexity of reconfiguration laws and how to enter and exit protections. Operationally, all conditions listed in FCOM are of not much significance. What to do if your controls have gone alternate in flight? Nothing, keep on flying as you were. Just don't perform windshear or GPWS escape with full stick back, keep an eye on the airspeed, OK? How much stick and for how long is needed to combat the unwarranted alpha prot pitching you up? Who cares, push the stick to get the attitude you need and prot disconnection will take care of itself, it is meant to be instinctive and it is.
Originally Posted by Chris Scott
In your eagerness to respond in a single post to several pages and many contributors, you have a tendency to select snippets of text out of context, and comment rather dismissively on them. In doing so, you misrepresent the contributor's argument. (I'm wondering if you suffer from a short attention-span - not unusual in hot-headed youth...)
I'm sorry Chris, if my caustic style caused you to believe I was going for a cheap shot here. To make my position clear: I do not find any of the theories that there was anything remotely rational in CM2's action and it was just misunderstanding and misapplication on his part plausible. He meant just to return to altitude? He busted it by a couple of thousand feet. He followed the flight directors? He pulled whether they were there or not. He was cognitively overloaded? For a while the only thing picked up by the CVR is stall warning. The aeroplane developed roll oscillation? Oh sure: maximum amplitude 11°, period approximately 10 seconds, damped actively and completely in 1:30 min. He tried to perform UAS procedure for very low level in cruise? He didn't say so and was persuaded by CM1 to ease a bit anyway but stall warning sent him into another pull-up frenzy.
Now let's have a look at the general state of the aviation safety; despite all the doom-sayers that overuse of automation is going to be the end of us all, year after year we are enjoying the record lows of accident rates, so we must be at least doing something right. Of course, not all or even the most of improvement in the safety record is attributable to automation but there is no evidence it reduced safety, especially if besides the dry statistics we choose to pay attention to all too numerous incidents where automation went ballistic and pilots saved the day, often without anyone noticing except their colleagues informed via internal safety bulletins. So if we (and I mean we as aviation community, not as PPRuNers) want to improve the chances of everyone landing safely by applying the lessons of AF447, we better make sure we understand what really happened, lest we apply the cures that are inappropriate and can turn out to be poisonous.
I do not know what made the whole crew to act as they did but I am pretty sure there are two things that won't prevent AF447-like accident from reoccurring: more raw data manual approaches and more practice in unusual attitudes recovery. Practicing any of them involve preparation and anticipation, things sadly lacking in AF447 case where onset of the trouble was very fast. 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 practicing eye-to-hand coordination in friendly skies. Also this kind of reaction is very rare and trying to present AF447 as typical of the current state of affairs is misinformed at the best.
I have mentioned that this is just another child-of-the-magenta case and this might be too imprecise; despite significant differences (performance and aerodynamics vs. lateral navigation) both AF447 and AA965 are subsets of the same archetype of accidents: pilots who find themselves on unfamiliar territory, are unable to recognize where they are and how to return to normal, eventually performing the action that results in their premature termination. That is absolutely not to say they were bad pilots: I'm pretty sure if they were presented with the scenario of their final flight, they would vehemently deny they would ever act according to it. As many around here very well know, difference between thought process in the air and on the ground is stupendous, especially at 4AM. Our unfortunate colleagues were suddenly thrown on scales and found lacking and even after final report we are not much smarter regarding what was missing.