LH A320 Rough Landing @ Hamburg

[Chris Scott]

Sidestick abuse... and how to avoid it.

In the light of all these illuminating exchanges more recently, I have EDITED my post on A320 side-stick [Mar04/18:07, currently Page12, #229]. These amendments have now also been added below during EDITing.***

Quote from gonebutnotforgotten [Mar12/20:46, currently #452]:
I have sat jump seat behind other coffee stirrers like him - and all those who regularly hit the roll stops) who really don't know what their flight controls are doing, haven't thoroughly thought through how the machine works, and haven't been taught to do so. I find that rather worrying.
[Unquote]

Having arguably over-contributed to this Thread (20 posts at the last count...), I see that the sidestick-abuse issue is still worthy of further comment. I made little attempt to describe how to handle the stick in my previous post, except to express the opinion that, with notable exceptions, inputs should be "short and often". The alarming over-control exhibited in the "instructional" (ouch!) video [see link in lamer's post of Mar06/11:49, currently Page 18 #345], is even worse than what I often observed from the detached point of view of the jump seat in about 12 years as a specialist line-checker on the A320 family.

Full stick one way followed by the exact opposite a split-second later, such as in the video, could be most kindly described as nervous "occupational therapy", in my opinion, whether the air is rough or smooth.
LET THE DUTY ELAC/SEC DO THE WORK...

Last month, there was a good discussion on this Forum; "Fly by Wire questio0n" (sic):
http://www.pprune.org/forums/showthread.php?t=313926
This was my two-pence-worth on how to use the sidestick, for the uninitiated (and the habitual "stirrers") , slightly clarified:

Re the sidestick, it's worth mentioning that there is a special armrest, adjustable in height and rake, for each pilot. The idea is to rest the flat of your forearm on it, wrist slightly raised. You do not actually touch the stick until you need to make an input.

For simple roll-rate demands, you can use your thumb for one way, and 1 - 3 fingers for the other way. For up demands, use your fingers; for down demands, your thumb. To do these different tasks, your wrist will twist to the necessary angle, but will not move up or down, or significantly sideways. Inputs are normally the most successful when small, short-duration, and frequent. The obvious exceptions are rotation on take-off, and a simple roll from one side to the other. ***

The stick can be moved in any direction, of course. ...the stick does take account of your hand's hook-action being stronger than its "slice". Although the pitch and roll-rate resistances are well harmonised, combinations of the two are the easiest to get wrong. The sticks do not move to reflect autopilot inputs. Normally the signal to the EFCS is the algebraic sum of the 2 sticks. But if one pilot wants to take control, he/she can press a red button on the stick (eliciting a 'gringo' announcement and warning lights). The red button is also used for AP disconnect.


*** [EDITING CLARIFICATION]

Pitch inputs are also best small, short-term, and often; except (1) rotation; (2) the flare, when countering the progressive forward trimming in land-mode; and (3) in recovery from a dive or steep climb.

CROSSWIND LANDING
In airborne sideslip, (usually delayed until decrab) the sidestick roll-input must be released as soon as the desired bank is achieved. However, the opposite rudder will have the effect of lifting the lowered wing again, so you may need to reapply the roll command intermittently, elsewhere referred to as "bumping". [See Post #449, et al.] Once both main L/Gs have touched down firmly, the stick can be kept slightly displaced in the direction of the sideslip. 5 seconds later, the FBW will revert to roll-direct mode (stick-to-aileron), and continuous into-wind aileron can (and should) be applied - in the conventional manner - until the wing ceases to be vulnerable to side-gust.

CROSSWIND TAKE-OFF
A small amount of into-wind aileron can be selected before starting the T/O run, avoiding "cracking" the spoilers.* During rotation, the upwind wing tends to rise in the conventional manner, and can be countered by retaining into-wind aileron. As the main L/G lifts off, any downwind rudder will be eased off, yawing the aeroplane into wind. This will temporarily assist the aileron. Half a second after lift-off, however, Normal Law in roll is introduced (AND the white cross on the PFDs has disappeared). At that point, any remaining roll input needs to be released.
5 seconds after main L/G lift-off, Normal Law also becomes fully effective in pitch. Stick-to-elevator control is now removed, and pitch-attitude can be refined by small nudges of sidestick.

* Roll-spoiler deployment can be avoided by placing the PFD white-cross so that its inner edge is not noticeably to the side of the centre spot.