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lion-g
20th Feb 2010, 16:20
Hi guys,

Just want to seek some advice on de-rotation of the airbus a/c on landing. Do you "land" nosewheel or do you hold the attitude until the a/c loses lift ? Can't seems to appreciate it.

Thanks a lot in advance.

Cheers

A-3TWENTY
20th Feb 2010, 17:42
I land the nosewheel

Superpilot
20th Feb 2010, 18:21
Land the nosewheel so as far as stick neutral

rudderrudderrat
20th Feb 2010, 18:38
Hi lion-g,

You could always cheat and see what the FCTM says.

DEROTATION
Applicable to: ALL
When the aircraft is on the ground, pitch and roll control operates in Direct Law. Consequently, when
the aircraft touches down, the pilot flies the nose down conventionally, varying sidestick input as
required, to control the derotation rate.
After touch down, when reverse thrust is selected (on at least one engine) and one main landing gear
strut is compressed, the ground spoilers partially extend to establish ground contact. The ground
spoilers fully extend when both main landing gears are compressed. A small nose down term on the
elevators is introduced by the control law, which compensates the pitch up tendency with ground
spoiler extension.
It is not recommended to keep the nose high in order to increase aircraft drag during the initial part
of the roll-out, as this technique is inefficient and increases the risk of tail strike. Furthermore, if auto
brake MED is used, it may lead to a hard nose gear touch down.

Zippy Monster
20th Feb 2010, 18:40
Agree - land it, but gently. The way I find I do it is once the main wheels are down, just gently release the back pressure on the sidestick until the nosewheel is down. Once it's down, release to neutral.

You don't want to release it too quick and slam it down, but presumably it's also not too good an idea to hold it up for too long (remember your pedals are giving you directional control through the nosewheel as well as the rudder.) Speaking of which, here (http://www.youtube.com/watch?v=nKlsmkzWVF4) is a good video of a pilot doing exactly that in a BWIA A340 at Manchester a few years ago.

lion-g
21st Feb 2010, 02:21
LOL

"What an extraordinary expression! Where on earth did that come from???"
I was wondering that too :) Somehow I read it in the FCTM as well :rolleyes:

Thanks for all your input ....

Can somebody shed some light or the exact technique on "landing" the nosewheel?

Do you relax the sidestick and do a "miniflare" just before moment of impact? Or according to the video mentioned above, it seems like he hold the landing attitude as long as possible until the lift reduces as the speed bleed off.

Any inputs are very welcome as I am VERY VERY new to this sidestick game.

Thanks again

Cheers

tom775257
21st Feb 2010, 02:50
I find personally:

A319: I haven't flown one for a few years, but I remember similar technique to the A320.

A320: After touchdown ease off back pressure, allow the nose to come down and just before the nose touches I 'blip' some back pressure to give a smooth touch down of the nose.

A321: After a smooth touchdown it needs a touch of forward pressure to prevent any pitch up with spoilers coming out, then rapidly release this back to neutral and some back stick to smoothly bring the nose down. Preventing any pitch up is especially important on this aircraft to prevent tailstrike.

I hear: A330: After mains touch a little forward pressure to land the forward MLG wheels smoothly then some back pressure as the nose comes down.

flyprototype
21st Feb 2010, 03:05
after your mains touch, you must '"accompany"the nose by releasing the stick.

it' s call accompanying landing. FCOM 2.3543

Microburst2002
21st Feb 2010, 07:52
I have read "de-rotation" in many other taxts...

try googling it and eliminating "medical". There is an NTSB pdf about hard langing vs derotation accidents.

English is a very rich language, isn't it?

Capn Bloggs
21st Feb 2010, 11:39
Even the shuttle pilots use it (towards the end of this video):

YouTube - Cockpit View of Shuttle Landing! (http://www.youtube.com/watch?v=XxGeo0ec-F4)

...although I prefer the word "de-flare", as that is exactly what is being done.

Did I hear you say "Roll It On!", Bloggs?? :}

rudderrudderrat
21st Feb 2010, 12:15
Agaricus bisporus. What Cheer? (Whatcha)

Oh my golly gosh and balderdash. Where did you get "Strewth!" from?

A rotation by x degrees (vertically in aviation, horizontally clockwise in printing etc.) could be cancelled by a de-rotation by x degrees in both cases. You'll find the term in lots of modern parlance, including Airbus manuals.

learner001
21st Feb 2010, 13:33
rotation:
moving POSITIVE (UP) around the lateral axis, pitching UP

DE-rotation:
moving NEGATIVE (DOWN) around the lateral axis, pitching DOWN

learner… ;)

clunckdriver
21st Feb 2010, 15:04
De rotation,thats right up there with,"at this point in time",{the long form of now} Or "going forward in time" {the future} or "negative cash flow"{your broke} "Colatteral damage",{missed the bad guys} Ah the age of Bafflegab is here!

divinehover
21st Feb 2010, 17:16
In the A319 I would gently fly the no wheel down as it wasn't at all an issue. You just dont want to loose elevator effectiveness and let the nose fall onto the ground. On the A346 you need to positively de-rotate the nose down. It very possible to be left with the nose in the air and run out of elevator control in the A346. On the A342/A343 I aggressively de-rotate after the first of the rear wheels touch to try and avoid the second thump that seems to haunt me.

DH

604guy
22nd Feb 2010, 16:04
rotation:
moving POSITIVE (UP) around the lateral axis, pitching UP

DE-rotation:
moving NEGATIVE (DOWN) around the lateral axis, pitching DOWN



Remind me......regarding rotation about the longitudinal axis…..banking to the left…..rotation and banking to the right de-rotation or is it the other way around. Always get that confused!

Bloody hell, rotation and de-rotation. Why is it that we as an industry insist on bafflegab again? Oh that’s right, we must keep up the pretense to the masses that we are superhuman after all.

TyroPicard
22nd Feb 2010, 19:36
For Bafflegabbers everywhere..
Can you produce a single English word for us to use instead of derotation? Blowed if I can think of one...

604guy
24th Feb 2010, 01:00
[I][/single English word for us to use instead of derotationI]

Um, in this context how about "lower"

To paraphrase DH....... Please ignore Agaricus bisporus and the nonsense he speaks. In the A319 I would gently fly the nose wheel down as it wasn't at all an issue. You just don't want to lose elevator effectiveness and let the nose fall onto the ground. On the A346 you need to positively lowerthe nose. It's very possible to be left with the nose in the air and run out of elevator control in the A346. On the A342/A343 I aggressively lower the nose after the first of the rear wheels touch to try and avoid the second thump that seems to haunt me.

I'm a great believer in KISS :}

lion-g
26th Feb 2010, 02:59
Hi guys,

Just to share my experience from yesterday. I had to "hold off" quite a bit to ensure the nose wheel touched down gently. Quite different from Boeing where I tends to ease the control column forward.

Will try again soon...

Thanks for all the replies ... keep them coming !!! :D

Cheers

notanastronaut
28th Feb 2010, 02:57
Could you kindly elaborate on the pitch up tendency at spoiler deployment.
Thanks,
NA

rudderrudderrat
28th Feb 2010, 09:23
Hi notanastronaught,

Could you kindly elaborate on the pitch up tendency at spoiler deployment.

The FCTM mentions this effect (please see earlier post) - but typically there is no explanation given. Either the center of pressure of the wing moves inboard (bigger effect of panels 5), or the airflow over the tail is changed (with panels 1 deploying).

It's a mystery!

AeroBoero
1st Mar 2010, 15:32
Just curious;

On the CFM engines when landing (and deploying reverse) I usually feel more the pitch up tendency as when landing with an acft with IAE engines.
Anyone noticed the same on the A320?