Originally Posted by
JustAnothrWindScreen
Thats what airline Captains do all the time and is not a tall order for a mere human. When you look at your watch, 9 seconds is an eternity.
Without trying to be overly critical of your opinion, I think that all of us would like to believe our own “press:” Supermen (and women), highly trained, laser-like mind, inerrantly finding the problem and whipping out a weird, but effective, solution. Would that it were so … but James Bond is still a fictional character.
Your characterization of 9 seconds being an eternity is, as I’m sure you recognize, a relative perception. Pointing up that relation is a pretty “standard” attorney response when a witness says “I only got a very brief view of the murder – only about 9 seconds.” The attorney calmly asks the jury to see how long 9 seconds really are … “Ladies and gentlemen, I’m going to ask you to hold your breath when I say ‘now’ and to hold it until I say ‘ok’ at the 9 second mark, and we’ll see just how long 9 seconds really is.” As Einstein once described, “When you are courting a nice girl an hour seems like a second. When you sit on a red-hot cinder a second seems like an hour. That's relativity.” The timing involved here is just as “relative.”
If you look at the animation of the FDR, the first couple of control applications and reversals (time marker 15:51 through 15:54) probably didn’t get the airplane terribly “out-of-sorts” with itself – at least to the point that the Captain would have immediately suspected the F/O was about to tear the tail off the airplane – and that is why the Captain asked “You alright?” in response to the F/O’s request for “max power;” which was said some 3 seconds into the “less than 9-second” ordeal. Again, view the animation of the position of the airplane during this brief period. Note how far the airplane animation actually moves. In calm air, this movement would probably be noticeable; but having just experienced an encounter with a wing-tip vortex, I don’t think the second encounter was a surprise – and certainly not one of ominous proportions. However, it is more than likely that, even without an immediately recognizable “tactile impression” of danger in the cockpit (despite
Graybeard’s comment, “Tactile feedback was in his butt"), the damage was probably already begun.
The next couple of control inputs and reversals probably DID get the attention of the Captain, but the response of the F/O, “Yeah, I’m fine” would have likely given the Captain reason to pause in his judgment, and additionally, the Captain was very likely evaluating and/or attempting to comply with the F/O’s request for “max power.” Immediately thereafter, he was either directing or encouraging the F/O with his comment “hang on to it, hang on to it.” It was at that moment that the airplane started a rather sizable yaw moment to the left – and there is very little doubt that the Captain would have missed that movement – however, I think THAT was the final straw, and the vertical stab departed the airplane. The time markers between those points are 15:57 and 15:59 – after which the data feed stops.
The Captain was not sitting in isolation, pre-loaded to see, recognize, and respond to a problem – particularly one of the magnitude that was developing. He observed and challenged; and he got what was likely determined to be a reasonable response. But from there it went down hill with the burners full on! I am as sure as I can be that these guys did not feel this scenario was unfolding over some lengthy time period.
Originally Posted by
DozyWannabe
They also spent a considerable amount of money coming up with their own report saying that the crashes were both likely to be a result of pilot input rather than a design fault with the rudder system - aren't corporate lawyers great? .
Yes, this is true; but would you expected to have Boeing, or anyone else for that matter, say, “Yep. Guilty. We’ve built the world’s most unsafe airplane.” I suspect that they were trying to walk the very fine line between telling the unbridled truth and perhaps scuttling the company; and out-right lying by claiming that there isn’t, and could not be, anything wrong with the airplane. I don’t believe either of those two extreme positions were accurate. It may well be that the engineers at Boeing don’t even know for sure, what the no-sh*t reason was behind those crashes. However, that the rudder was involved in some way is very hard to argue against. But, if you don’t know (or can’t admit) how do you address the situation?
Originally Posted by
DozyWannabe
Pointless speculation here, but the problem was with the PCU, which could jam and send the rudder into a hardover in the opposite direction to that commanded by the pilot. I've wondered for a while whether both those aircraft encountered some kind of turbulent air and when the rudder was used to correct, the PCU jammed and this 'reverse hardover' defect came into play. .
I suspect that laying the responsibility on the PCU was a reasonable route to follow. Was it the REAL cause? I don’t know. My guess is that Boeing would say that it was prudent to re-address the rudder control issues from top to bottom, including the PCU. In fact, I think that is exactly what they DID say – or something close to that.
Originally Posted by
DozyWannabe
Either way we're drifting off topic, although it's useful to note that no manufacturer is happy about admitting their arcraft has a fault.
My point as well.
Originally Posted by
bomarc
air rabbit
if the rudder wasn't the problem on the 737 pit and cos, then:
why is there so much training in rudder hardover recovery for this plane?
To my knowledge, the training received by pilots flying the B-737 (all series) in addition to the systems taught in ground school, has to do with “cross-over” speeds – where slower airspeeds allow the rudder to be more effective at controlling roll and higher speeds allow the ailerons to be more effective at controlling roll. Therefore, if you have a rudder/roll problem, accelerate to above the cross-over speed to be able to control the roll with the roll control for the airplane, the ailerons.
why are there now memory items for turning off the hydraulic power to the rudder?
Because it makes good sense. If there is any possibility that a powered rudder is causing or exacerbating an existing problem, it would be prudent to eliminate the powered rudder input.
why is there a pressure reduction mechanism?
Because it makes good sense. Even if the existence of a powered rudder had nothing to do with the accidents, it would be good press to take the extra steps to include a rudder pressure reduction system – and, it would be like chicken soup – it couldn’t hurt – particularly if the system prevents pressure reduction in those cases where
having the rudder powered is a good thing – like on an engine failure during takeoff.
why are crossover speeds so vital a part in flying the plane now?
I don’t think that cross-over speeds are any more vital now than they used to be. It’s just that more people are more aware of what they are, what they mean, and how that knowledge may be able to save your butt.
believe me, it is much easier a plane to fly with the old "speeds", (except for the lack of rudder hardover protection)
Well, I’m not terribly sure about that. I fly the B-737 and it’s like any other change made to an airplane. IF you were aware of what cross-over speeds were, how they affected the handling characteristics of the B-737 (or any other airplane for that matter), and used that knowledge if or when necessary, I’m not sure that a so-called “rudder hardover” would be a problem.
Originally Posted by
bomarc
I know people who actually believe that both crashes were completely pilot error. Perhaps these are the same kind of people also would blame the pilots for the electra crashes in the 50's.
Yes, I’m sure that is true. There are also people who believe that it was a Tomahawk missile that crashed into the Pentagon on 9/11. There are others believe that extraterrestrial aliens are roaming the streets of Roswell, New Mexico. Maybe they should all get together and have a picnic?
Originally Posted by
bomarc
and yes to the chap who mentioned corporate lawyers! they do earn their money.
Sometimes they do. Sometimes they don’t.
Originally Posted by
bomarc
I went to the NTSB hearing in the DC area (near the springfield shopping mall for those familiar with the area). One thing that did come out was that more recent standards of certification would indicate that the 737 in its present form would not have been certified. Could this concept be useful with the airbus 300?
Are you saying that the “new” certification standards would not allow for the B-737NG to be certificated? And, I’m sure you’re aware that current standards wouldn’t allow many airplanes still flying to be certificated either. So, what would be your recommendation? Ground them all?