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View Full Version : Rudder pedals back-drive or not during Autopilot(autolanding)?


YaYoSky
27th Sep 2010, 15:49
i know boeing and erj both have rudder servo to back-drive the pedal during autolanding. but airbus just has trim actuator. In A320 AMM i read that AP will command AP rudder trim order, so the pedals will move or not as the AP rudder trim order?
thx:rolleyes:

411A
27th Sep 2010, 21:08
L1011, the first truly automated wide body airplane in commercial service...
Rudder shifts to parallel operation (IE: rudder pedals move upon inputs from the APFD system(s), once automatic approach/land track (autoland) is established.
Keeps the pilots IN the loop.
Fail operational.
TriStar, still (to this very day) to which others are compared.
IE: the GOLD standard.

NB.
Must be experienced to be believed.
Lockheed, unsurpassed in automatic ops.

Having said this, 'others' have 'caught up'.
Then, one wonders...what has taken them so long?:ugh::E

FCeng84
27th Sep 2010, 23:08
This is and always has been a Boeing Commecial Airplane Design Philosophy for all pilot control inputs impacting primary control surfaces and the engines. During autoflight operation the wheel, column, pedal, speedbrake lever, and throttle positions all reflect what the automatics are doing. High priority is given to pilot awareness of what the automatics and/or the other pilot are doing.

grounded27
28th Sep 2010, 09:17
Having said this, 'others' have 'caught up'.
Then, one wonders...what has taken them so long


Power on the hill, lockheed must have had the financial power to get the FAA to approve the L1011. Hmm, why does lockheed not have cutting edge aircraft in production for the commercial market today?

PEOPLESX
28th Sep 2010, 09:59
In A320 AMM i read that AP will command AP rudder trim order, so the pedals will move or not as the AP rudder trim order?

The pedals will be moved in AP trim operation to "indicate" also the new neutral position to the pilots and, of course, to suppress uncommanded rudder movement during AP disengagement.
The AP or FCS inputs to the rudder for dutch roll compensation or turn coordination (if a roll input is made, the ailerons and the rudder will move, even when the pilot only selects the side stick) is not followed up to the pedals.

Mike

PS: my English-skills aren't the best an i try do get better, so if you think i did "major" mistakes in my explanation -> let me know

YaYoSky
28th Sep 2010, 15:52
PEOPLESX:The pedals will be moved in AP trim operation to "indicate" also the new neutral position to the pilots and, of course, to suppress uncommanded rudder movement during AP disengagement.
I agree with you at this point. But i wonder that if the pedals without trim or servo actuator was used, how to suppress uncommanded rudder movement during AP disengagement(especially cross wind, low altitude). Can FCS mitigate the transient and continue a safe manual landing?:)

411A
28th Sep 2010, 16:18
Power on the hill, lockheed must have had the financial power to get the FAA to approve the L1011.

Could well be true.
However, about two years ago, I met a retired Boeing design engineer.
His comments were to the effect...'when we had a first close look at the TriStar autoflight design, it was then that we knew...Boeing was way behind.'
His exact words...way behind.

hetfield
28th Sep 2010, 16:30
TriStar

What's that?

PEOPLESX
28th Sep 2010, 20:07
I agree with you at this point. But i wonder that if the pedals without trim or servo actuator was used, how to suppress uncommanded rudder movement during AP disengagement(especially cross wind, low altitude).
I'm sorry, "suppressed" maybe the wrong wording for that. Sudden rudder movement from the actual position to the new (trimmed) neutral position should be prevented.

Can FCS mitigate the transient and continue a safe manual landing?
For automatic landings both AP's must be engaged, if really both AP's will be disconnected, i don't know how soft the transition is, sorry.

Meikleour
29th Sep 2010, 11:40
Peoplesx: Single Autopilot Autolands are permitted on the Airbus A320/330/340!!

Company SOP may be engage both autopilots but that is not a limitation.

YaYoSky
29th Sep 2010, 17:12
[QUOTE][/I'm sorry, "suppressed" maybe the wrong wording for that. Sudden rudder movement from the actual position to the new (trimmed) neutral position should be prevented.]

Thanks for your explanation!

PEOPLESX
29th Sep 2010, 23:21
Peoplesx: Single Autopilot Autolands are permitted on the Airbus A320/330/340!!

your right of course, i checked this today, was also new for me :ok: