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He stepped on the Rudder and redefined Va

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He stepped on the Rudder and redefined Va

Old 11th Oct 2013, 21:35
  #361 (permalink)  
 
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And that the Airbus 300 didn't have such a limitation published.
Does any transport aircraft?

I'm not questioning your credentials just highlighting who you are and the fact that you are like a dog with a bone. I think it's only fair that people know who they're arguing with.

You only answered one of three questions in my previous post.

Does thirty and a half years count as novice SSR?
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Old 11th Oct 2013, 21:44
  #362 (permalink)  
 
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No, no, no, no, no! The limitation is to not repeatedly reverse control deflection. Not the amount control movement versus airspeed as you put it.

Which other transport aircraft have that limitation? It's an easy question that even a novice can answer.
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Old 11th Oct 2013, 23:40
  #363 (permalink)  
 
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Not to keep going back to the same A300 crash but does anybody know exactly where rudder inputs are measured? Mechanically at the rudders or before the rudder actuator which apparently was the cause of the MIA uncommanded rudder inputs. This has been reported to be a hydraulic valve malfunction to the actuator. Was the rudder pedal input measured before or after the faulty valve?
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Old 12th Oct 2013, 00:06
  #364 (permalink)  
 
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Bubbers, the same place that you've been told before.

SSR,
reversals bad,
You know that despite NOT seeing a placard. So how do you know?

The A300 didn't have what limitation published?

Could you also explain how CRM is in any way relevant.
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Old 12th Oct 2013, 01:26
  #365 (permalink)  
 
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RUDDER TRAVEL LIMITING The rudder travel limiting system modifies control inputs to the servo controls, to vary rudder travel in relation to airspeed (Vc). Limitation is such that the maximum deflection which can be achieved by the rudder remains lower than the deflection which would induce limit loads on the structure, throughout the flight envelope.

The system is composed of: • A variable stop unit consisting of an articulated lever operated by an electro-mechanica]. actuator, end a transducer unit detecting lever position. These items are all mounted on a frame assembly located downstream of the differential between the AP and yaw damper actuators. • Two control and monitoring computers designated FLC (Feel and Limitation Computer). • One RUD TRAVEL control panel, one PITCH FEEL & RUD TRAVEL maintenance panel and five electrical power supply circuit breakers.

The variable stop lever is operated by an electric actuator which consists basically of • Two AC motors, supplied with 26 V ,400 Hz • A single reducting gear actuated by both motors, which are rigidly connected. • A nut/screw system, driven by means of a torque limiter • Mechanical end of travel stops • A torque limiter provided to protect the reduction system from any abrupt jamming of the output shaft, particularly when it reaches the mechanical stop.

The actuator is servo controlled and is monitored through a transducer unit driven by variable stop lever movement. The transducer unit, comprising two inductive transducers is identical to the one used in the spoiler control system.

In the event of a rupture or disconnection of an actuator attachment a retention rod limits actuator movement to prevent it from jamming the variable stop lever. A spring returns the lever to the ‘low speed' position where full control deflection (÷ 30°) is possible.

Feel and limitation computer contains the circuitry required for two functions : Rudder travel limiting and pitch feel.

The FLC is a digital computer comprising two different computation channels: • Rudder travel limiting/pitch feel control channel • Rudder travel limiting/pitch feel monitor channel.

Safety of the systems is ensured by control and monitor channel programs which are intentionally different

Monitoring of digital computations which are performed by control and monitor channels with the same input data, achieved by comparison between the results of both channels, by mean of analog comparators.
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Old 12th Oct 2013, 01:33
  #366 (permalink)  
 
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Lam, no the exact rudder pedal FDR reading, I assume, comes from a mechanical sensor at the pedals but it would be cheaper to do it at the actuator. I know there is rudder pedal and actual rudder movement sensing. Thought some maintenance guy could verify that. Loosen up.
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Old 12th Oct 2013, 02:59
  #367 (permalink)  
 
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LSM, I know I did one letter wrong. I forgot the e. Asking a question because I have no way of finding it from someone who know isn't lame, it is just the only way I know to get an answer. Where is the rudder pedal sensor for FDR source located on an A300.
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Old 12th Oct 2013, 03:06
  #368 (permalink)  
 
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CRM for me was quite simple. I just said fly any way you want and don't bend any rules, fly safely, keep the passengers comfortable and please don't show me something I have never seen before.
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Old 12th Oct 2013, 09:46
  #369 (permalink)  
 
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bubbers,

Where is the rudder pedal sensor for FDR source located on an A300.
See my post #151. The report talks of rudder control cable stretch. That implies that the rudder pedal sensor is located near the pedals.
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Old 12th Oct 2013, 09:58
  #370 (permalink)  
 
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Originally Posted by bubbers44 View Post
Not to keep going back to the same A300 crash but does anybody know exactly where rudder inputs are measured? Mechanically at the rudders or before the rudder actuator which apparently was the cause of the MIA uncommanded rudder inputs. This has been reported to be a hydraulic valve malfunction to the actuator. Was the rudder pedal input measured before or after the faulty valve?
The sensor for the rudder pedal position is located under the cockpit floor, it is directly attached to a bellcrank aft of the FO's rudder pedals.

The rudder position is measured with a sensor attached to the lower corner of the actual rudder, directly measuring the movement of the rudder relative to the vertical fin.

Look, I understand that for reasons known only to yourself, you're searching for ways to blame this on the airplane and not the pilots. I have to ask, do you imagine that the NTSB, upon finding that there were multiple rapid rudder reversals which caused the vertical stabilizer failure just said: "Hey, let's blame it on the pilots and not investigate any other possible sources of the reversals. That way we can wrap this up and go home early" ?

That seems to be the common thread of all your posts, that the NTSB didn't investigate any other possible causes of the rudder reversals. That the reversals were caused by something else and that the NTSB just blamed it on the pilots because that was what was easy. I'd recommend that you go read the NTSB report, yourself. You'll find that they spent a lot of time on investigating everything that might have caused the ruder reversals. This included inspection of the system components recovered from the crash, analysis of the rudder control system together with the yaw damper and autopilot system, the rudder servo system, and extensive testing of all of the above on identical aircraft. A great deal of that testing was focused the question: "Is it possible that the rudder position and rudder pedal position data which indicates pilot input could have bee caused by something *other* than pilot input" It's not that nobody ever thought to ask the question. They did. And the answer was: "probably not"

As as far as your references to the MIA incident, that was due to an autopilot yaw actuator clutching mechanism which failed to disconnect when the autopilot was selected off. This has already been discussed in this thread previously. That also was investigated by the NTSB in their investigation of AA587. The airplane was being hand flown, the autopilot had not been engaged so a disengagement failure was improbable, the controls had been checked on the ground and there was no interference as was present in the MIA incident, and the Yaw control autopilot servomotor was disassembled and examined and the autopilot yaw input was found to be disengaged.

So, yes, the NTSB *did* consider that this might be related to the MIA incident. Yes, they *did* investigate this possibility, and no, there was nothing which indicated this was the same cause.

Last edited by A Squared; 13th Oct 2013 at 13:59.
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Old 12th Oct 2013, 11:36
  #371 (permalink)  
 
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Quote from bubbers44:
Not to keep going back to the same A300 crash but...

Quite: as any casual passerby might conclude, this thread is mainly an argument about CRM between two forumites whom no one wants to share a cockpit with, and the handling qualities and placards on Sabreliners - no longer simply a serious discussion of whether rapid, alternating, full-travel rudder applications are warranted, and need(ed) to be considered in the design and certification of large jet transports.

Tubby, HN39 and A Squared,
Thanks for bringing us back to reality; not that facts and logic are likely to silence the peanut gallery...
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Old 12th Oct 2013, 13:14
  #372 (permalink)  
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Not often my patience runs out.

Several folks have been sidelined. Perhaps, now, we can get back to the discussions at hand ...
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Old 12th Oct 2013, 13:21
  #373 (permalink)  
 
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Originally Posted by john_tullamarine View Post
Not often my patience runs out.

Several folks have been sidelined. Perhaps, now, we can get back to the discussions at hand ...
If you had better CRM skills you would have been able to sort that out without banning people
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Old 12th Oct 2013, 13:30
  #374 (permalink)  
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Guess I'm just an old has been failure, then ?
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Old 12th Oct 2013, 13:36
  #375 (permalink)  
 
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Just in case it wasn't obvious, that was completely tongue in cheek.
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Old 12th Oct 2013, 16:05
  #376 (permalink)  
 
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Quote from A Squared:
If you had better CRM skills...

Hang on a minute! In my experience, it's often those who lack them the most who try and play the CRM card. Must say I didn't think you were in that category.

Quote from A Squared:
Just in case it wasn't obvious, that was completely tongue in cheek.

Oh, really? Having read the last 4 posts one-by-one. this old fart was convinced you were serious...
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Old 12th Oct 2013, 16:13
  #377 (permalink)  
 
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Originally Posted by Chris Scott View Post
Quote from A Squared:
If you had better CRM skills...

Hang on a minute! In my experience, it's often those who lack them the most who try and play the CRM card. Must say I didn't think you were in that category.

Quote from A Squared:
Just in case it wasn't obvious, that was completely tongue in cheek.

Oh, really? Having read the last 4 posts one-by-one. this old fart was convinced you were serious...
OK, well it was supposed to be a joke. Take a look at my post. See the thingy? To me that means "I'm being a smart-ass pot stirrer, and the fact that it's smiling means that it isn't particularly serious.

What does that emoticon mean to you? Apparently it means something different to you that it does to me.
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Old 12th Oct 2013, 17:37
  #378 (permalink)  
 
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Quote from A Squared:
OK, well it was supposed to be a joke. Take a look at my post. See the thingy?

I get it now. Never did properly understand these new-fangled emoticons. Okay, in view of my advancing presbyopia, I'll turn up the browser magnification in future!

But it's not little me that you need to mend fences with...
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Old 12th Oct 2013, 17:41
  #379 (permalink)  
 
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Originally Posted by Chris Scott View Post
But it's not little me that you need to mend fences with...
If you're referring to John Tullamarine, I'm hoping any misunderstanding has been clarified ... . John?
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Old 13th Oct 2013, 01:13
  #380 (permalink)  
 
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I won't post on this thread any more. I have made my statement and thanks for the info on mechanical rudder info. That is all I WANTED.
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