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Old 2nd Feb 2007, 05:06   #1 (permalink)
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A-320 autothrust complexity: a 'high-tech advance' or nerd arrogance

This question is totally sincere.

How do the hidden/subtle traps improve safety compared to the B-757/767 or even with the A-300/310?

Were the Airbus factory pilots given little input in this area, or were they simply worshiping at the "high-tech altar", allowing as much complexity as available with few thoughts given to how pilots think-that is, those who prefer logic. One example is a hand-flown go-around with no flight directors. One must select green dot speed or so, before the thrust "levers" are pulled back to the climb detent at clean-up altitude, i.e. 1500' agl. The brilliant machine will command idle power if not done correctly.
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Old 2nd Feb 2007, 08:24   #2 (permalink)
 
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After years of flying aircraft with more conventional thrust systems, I have to say that the airbus system makes complete sense and becomes natural in no time at all.

Not saying it is better or worse than any other system just that it is very simple and easy to use.
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Old 2nd Feb 2007, 08:38   #3 (permalink)
 
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One must select green dot speed or so, before the thrust "levers" are pulled back to the climb detent at clean-up altitude, i.e. 1500' agl. The brilliant machine will command idle power if not done correctly.
It's got to have a target when you engage it otherwise it doesn't know where to go! It doesn't have to be green dot. All quite sensible really.

Also don't forget, a simple button press puts the levers completely back under your own control (which I think is wherer they should be when manually flying - but that's a totally personal preference).
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Old 2nd Feb 2007, 09:13   #4 (permalink)
 
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Manual flight - manual thrust........
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Old 2nd Feb 2007, 10:35   #5 (permalink)
 
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I agree with Don. Makes sense very quickly.
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Old 2nd Feb 2007, 11:05   #6 (permalink)
 
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If in doubt, read the FMA.

It'll tell you, every time, what the automatics are doing with the thrust.
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Old 2nd Feb 2007, 11:22   #7 (permalink)

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IO, reading your post, it looks like you have already made up your mind.
Why ask us?
I have been using the fabulous 320/330s for fifteen years now and I'm not dead yet. Isn't that amazing?
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Old 2nd Feb 2007, 12:52   #8 (permalink)
 
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One must select green dot speed or so, before the thrust "levers" are pulled back to the climb detent at clean-up altitude, i.e. 1500' agl.
Havent seen it yet... how did you do your approach? Manual with A/THR in selected?

Now Im curious too.
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Old 2nd Feb 2007, 21:12   #9 (permalink)
 
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The brilliant machine will command idle power if not done correctly.
Not, if you insert a selected speed.
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Old 2nd Feb 2007, 22:22   #10 (permalink)
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In most 'current spec' Airbii FBW a/c that I'm aware of, on selection of TOGA the FDs come back on and ATHR arms.

Now earlier software specs did have some subtle but important changes so I think it's important to find out just what spec a/c (or sim) you're talking about .

We had a situation in our fleet where an a/c that we had acquired from a previous operator (iso direct from AI) had a different response to TOGA application and sounds similar to what IO has described! It was an exciting ride for the crew (admittedly many moons ago now) when all the thrust came off!

With current spec a/c this has been resolved.
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Old 3rd Feb 2007, 03:07   #11 (permalink)
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Quote:
The brilliant machine will command idle power if not done correctly
Actually reverts to the approach speed or the speed prior to the missed approach, whichever is higher, please correct me if I am wrong.
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Old 5th Feb 2007, 05:28   #12 (permalink)
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We are in Initial training (full-flight). But our Aircraft Operating Manuals are very well-written and both our training syllabus and the Instructor Pilots are the best around,in order that guys like me can have a good chance to get through ok .

The daily briefing study guides help condense much of the important information.

Was much of this system designed only to allow a small (weight) cost saving, or did the designers intentionally disregard test pilot input regarding normal pilot interface, assuming that it was present? From the studies of the factory pilots' A-320 airshow accident (no advance to TOGA detent) and the A-330 test flight, what a cruel irony, somehow.

The B-757 autothrottles were nothing like this, and I doubt that the system interrelationships on the B-737, F-100/28 and the Dornier 328 can compare to the various complexities, i.e. go-around at an intermediate altitude, with or without an autopilot and/or flight directors. I.e... Go momentarily from CLB to the TOGA detent, then back, but check also that the FMA says .........and a missed app. altitude is set on the FCU/FMA......This is not how pilots with traditional airmanship skills think, that is, those with 10-20 years flying real aircraft: DC-9s and 757s etc. Maybe airmanship skills were also disregarded during the A-320 design, allowing an extremely low level of experience to be substituted by technology (thereby never allowing additional, significant airmanship/flying skills to be acquired nor developed in this type of aircraft...never mind total "in the loop" awareness).

How do aircraft designers decide to incorporate unnecessary complexity and disregard the safety implications? Were weight savings the ONLY priority?
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Old 5th Feb 2007, 09:06   #13 (permalink)
 
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Okay I have read the above post by Ignition Override at least 3 times and it makes absolutely no sense whatsoever.

As I said before, I find the Airbus system simple and intuitive and at no time does it vary with the rules of common sense or airmanship. It is not better or worse than any other system just slightly different.

I also believe that the auto thrust system, along with the joystick, provided a significant weight saving.
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Old 5th Feb 2007, 10:08   #14 (permalink)
 
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One must select green dot speed or so, before the thrust "levers" are pulled back to the climb detent at clean-up altitude, i.e. 1500' agl. The brilliant machine will command idle power if not done correctly.
???not really, not the airbus I fly anyway...
At Go Around mode engagement, the target speed becomes Vapp or the current speed if higher. At acc alt, the target becomes green dot. No need to select it and I don't see how the thrust would go back to idle???
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Old 5th Feb 2007, 10:13   #15 (permalink)
 
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I've used it for years and years now and find it easy to use however I can't help feeling that Airbus "re-invented the wheel" just for sake of it and to be different from Boeing. I can't actually think of anything it does better than a standard system but I can think of several gotchas and complications that arise because of the design. IMHO it's one of the weakest parts of the a/c and they would have been better off putting a standard system in.
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Old 5th Feb 2007, 10:27   #16 (permalink)
 
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IO,

Check you PM's
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Old 5th Feb 2007, 12:08   #17 (permalink)
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The reversion is to the SPEED mode, power goes to idle because you have accelerated past the current selected speed, just pull the nose up for thrust. I agree with previous opinions in favour of the system, traps like TOGA LK, no FD go arounds, forgetting to arm the approach prior to managing the speed are easily dealt with.
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Old 5th Feb 2007, 22:28   #18 (permalink)
 
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Quote:
From the studies of the factory pilots' A-320 airshow accident (no advance to TOGA detent)
They were not factory pilots, they were Air France pilots. They would have got TOGA even with trust levers firmly stuck at idle if they only made that flypast 75 feet higher. You see, alpha floor is disabled below 100ft RA.

On the sim Ive flown (if im free to use the expression) if you fly managed, your target becomes 250kt (adjustable through FMS) or green dot (if you fly selected). If you dont like what your ATHR is doing - disconnect it as you pull it from TOGA to CLB. Ah yes, theres airboos peciuliarity - ATHR is armed every time you make go-around so you have to press zee red bootons if you want to fly manually. Must be tough if you came from Bing.
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Old 5th Feb 2007, 23:25   #19 (permalink)
 
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Max Angle - unprecendented cockpit commonality (and by extension much simpler conversion training) across the A320/330/340 range was the long term plan when they designed that system, along with attempting to provide a more comfortable working environment, given the technical and managerial pressures on the modern pilot.

IO - I'm sure it'll get easier for you as you get further into the training. If you've gone from DC-9 to B757 I'm sure the FMS must have seemed like a strange box of tricks at first!

Either way you've got a job I'd love to do and I really hope it works out for you. The engineers who designed it were genuinely trying to make your life easier. That some people chose to present it as taking the pilot out of the loop was not the original intention of those who designed the system, and that I have from the horse's mouth.
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Old 6th Feb 2007, 00:14   #20 (permalink)
 
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Well you can have commonality across types with any system as long as it's common to all of them, you don't need to design a new system to achieve it. I am an Airbus fan and really think it's a good machine but the interface with the autothrust system is not one of it's best features in my opinion.
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