3
$\begingroup$

Pilots perform perfect manual landings almost all the time with the nose wheel touching down softly and elegantly. When landing an aircraft of any size really more so for the jumbos and super jumbos, this seems like an incredible feat given their weight and the speed at touchdown.

Apart from training, what design features or systems aid the pilot in achieving a soft nose wheel touchdown? Are there any features to help pilots in the event of an accidental abrupt push of the yoke during touchdown?

| improve this question | | | | |
$\endgroup$
  • 6
    $\begingroup$ The elevator, mostly. $\endgroup$ – acpilot Feb 15 '18 at 19:09
  • 2
    $\begingroup$ And the pilot of course. $\endgroup$ – user3528438 Feb 15 '18 at 19:57
  • 2
    $\begingroup$ Note that while the weight might be big, most of it is supported by the main wheels. The nose wheel only supports about 2–4%. $\endgroup$ – Jan Hudec Feb 15 '18 at 22:18
6
$\begingroup$

The longitudinal stability of the aircraft.

Aircraft are designed so that at any given elevator position they maintain a corresponding angle of attack¹. Any decrease in AoA creates pitch up moment to increase it and vice versa.

At touch down the pitching moments change a bit, but the general tendency remains, so without change in the elevator position, the plane will tend to keep the nose wheel off the ground. The nose only touches down when the pilot eases the back pressure on the control column, or the plane slows down enough that the elevator efficiency decreases below what is needed to keep the attitude.

The pilot just has to ease the back pressure gently and not slam on the brakes until the nose wheel is on the ground, because brakes do generate significant downward pitching moment (this applies to all vehicles; you can feel it in a car quite well).


¹ except modern fighters, but there the control computer emulates that behaviour, otherwise they wouldn't be controllable.

| improve this answer | | | | |
$\endgroup$
  • $\begingroup$ Does your footnote imply that modern fighters are not designed? ;) $\endgroup$ – Zeus Feb 16 '18 at 7:34
3
$\begingroup$

Having the airplane in proper (elevator) trim as the power is reduced prior to touchdown, flying the nose wheel onto the runway by relaxing the back pressure on the yoke while the elevator is still effective and practice.

| improve this answer | | | | |
$\endgroup$
1
$\begingroup$

While Jan Hudec’s answer is certainly correct, I think some credit should be given to devices like flaps and vortices generators that improve flight characteristics with higher angles of attack. Without them, pilots would have to land faster, with a more nose down attitude, which would make it more difficult to set the nose down softly.

| improve this answer | | | | |
$\endgroup$
  • $\begingroup$ Without flaps, aircraft would land faster, but generally with a nose higher attitude, because flaps increase the lift, but reduce the maximum angle of attack. $\endgroup$ – Jan Hudec Feb 18 '18 at 17:49

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.