PPRuNe Forums - View Single Post - Take off with snow on wing
View Single Post
Old 25th Apr 2012, 21:29
  #382 (permalink)  
AirRabbit
 
Join Date: Apr 2005
Location: Southeast USA
Posts: 801
Likes: 0
Received 0 Likes on 0 Posts
The Patience I Started With is Waning Quickly

Mr. Doves:

First, I am going to ignore the blatant insult, in the hope that it was only because you cannot understand my position … because of issues you cannot understand or choose to ignore. With all due respect … and, unfortunately, I fear, what is actually due with regard to that respect, is quickly expiring! You claim to know “exactly what happened,” and you cite the singular source for “knowing” all you say you know is that NTSB report … and I would presume, only, that report. The clear error you are making is believing only what you want to believe of that text and ignoring the blatant inconsistencies in that very same text.

Sir, as I believe I’ve said previously, I am fully aware of where you obtained the information you have “quoted” in your posts here. I am also aware, at least I believe, that the English language is not your first language (and if correct, you have my compliments for being as conversant as you are in English – I am conversant only in English – one of the not-so-admirable traits many of us Americans share…) but in that understanding there may be some room for your apparent misunderstanding of what is said in that report.

As merely one example of the confusion I am experiencing … are we who read your posts, to understand that if you do not hear the other pilot in your cockpit actually say out-loud, “Vee R” or “Rotate,” and failing to hear that verbal call-out you would not rotate? If you pass “Vee One” speed, later arriving at “Vee Two” speed … how is it that, in your opinion, you believe that the airplane did not achieve “Vee R” or “rotate” speed? Oh, by the way, one error in your reading of the transcript, sir … is your statements regarding “V2 speed” … the computed, briefed, (and believed set) “Vee Two” speed was actually 144 knots, and that is actually 4 knots higher than “Vee R” speed, which was also computed, briefed (and believed set) at 140 knots – although, admittedly, I’m at a loss to understand the significance you seem to attach to that relationship – whether it was the 4 knots the crew briefed (and most believe) used … or the 2 knots that you state. And NO, it’s not a requirement to call-out “Rotate” – and, while there are certainly some who do, not all flight crews make that call.

I also see that you note it wasn’t long after reaching “Vee Two” speed that the CVR transcript indicates the sound of the “stick shaker” begins. What that CVR transcript does not show is that on the actual recording there were very clear sounds of substantial buffeting – in fact, the buffeting noise was almost distracting to anyone listening to the CVR for the remainder of its recording. The airplane had not merely exceeded the AoA at which the stall warning was to be activated – it also achieved an AoA at least equal to, and very likely well beyond, the critical (stall) AoA – putting the airplane into an aerodynamic stall – from which all the obtrusive buffeting noise was generated.

Interestingly, you say that you are familiar with circumstances where it usually “…takes 5 to10 seconds (as you say "...the normal rate beeing 3° per second") to achieve a normal take off attitude of 20°” My suspicions are that you might be surprised to learn that I completely agree with your statements here … as, I too, am familiar with similar time requirements to rotate from a normal 3-point, ground contact position, to that normal takeoff attitude … although we used 18 degrees as “normal” … I’ll not quarrel with 20 degrees. At 3 degrees per second (a traditionally normal takeoff rotation rate) would take something on the order of 6 to 6 ½ seconds to achieve that normally achieved 18-20-degree attitude. With some of that waning respect I have left, I would question why it is that you choose to disbelieve, or you choose not to apply any relevance to the fact that the airplane rotated from the “3-point ground contact position” all the way to an attitude that exceeded the critical AoA (some witnesses said the pitch attitude was above 40 degrees) in in something on the order of a half to a third of the time it should have taken to rotate to what you describe as a “normal takeoff attitude.” For what it’s worth, you are not alone in that lack of understanding or that disbelief! But it happened. The facts are there. Clearly. It’s evident in the transcript, but those facts – as blatantly incongruous with other facts as they are – they are completely without comment, and are clearly indicative of some other factor that was either overlooked or was not given sufficient consideration, or was (and I do not like saying it) either deliberately or ignorantly suppressed in the deliberations that followed. The question remains … why would a B-737 rotate from a 3-point ground contact position to an attitude that puts the airplane at or beyond the critical AoA into an aerodynamic stall and do so well short of the time it would normally take to rotate only to 18 – 20 degrees? Is there anyone who really believes it was the F/O that “snatched” the airplane to that kind of attitude in that short period of time?? … when he had just stated that he was only going to rotate to get the nose gear into the air and “…just let (the airplane) fly off the ground”?? No one addressed this terribly obvious question. Additionally, after getting airborne, the transcript clearly shows the Captain repeatedly urging the F/O to move the control column “forward” … “come on forward” … “forward” … “just barely climb” … “we only want 500” … “forward.” Why doesn’t anyone question what that conversation was all about – and more importantly – why didn’t the F/O do what the Captain was urging him to do! Why didn’t someone take note of the fact that the Accident Report also includes statements from the airplane manufacturer that clearly shows that there was a “known tendency” for that airplane to “pitch-up” and/or “roll-off” when subjected to very minor amounts of freezing precipitation?? It seems more than just a little strange to me that such a potential was virtually ignored in the report and certainly was ignored in the conclusions reached ... particularly given the level of tragedy that occurred.

So, Mr. Doves … you continue to advocate a choir to sing the mantra that you so fervently desire … I’d just ask that if you’re going to put confidence into a report – that you do so with the ENTIRE report – and not selectively pick and choose portions of the report that seem to match and completely disregard any and all of those points that are horribly outside of any reasonable boundary for what you’ve chosen to believe.
AirRabbit is offline