Nose pitching up after landing

[Artie Fufkin]

Have had a couple of landings recently where, after touchdown and deployment of ground spoilers, the nose has suddenly wanted to pitch up requiring a substantial elevator input to arrest the raising nose.

Does anyone know why this might have happened? I fly the B737-300 if that helps.

[Empty Cruise]

Spoiler deployment? Anyway, using brakes normally balances it nicely.

[Dream Land]

Trying to do the touchdown while steadily increasing pitch will put you on the runway a little slow and nose high, then spoiler deployment occurs, either change your technique or try using some auto brake.

[BOAC]

Folowing on from Dreamland's comments, is it possible you 'normally' land with autobrake but did not on those two?

[SNS3Guppy]

On the 747, I see a pitch with deployment of autospoilers, with autobrakes in use. By keeping an eye on the speed brake handle, applying slight forward pressure (or releasing slight back pressure, as you will) at the same rate the speed brake handle comes back seems to do the trick.

[Permanent Standby]

Spoiler deployment on landing with an AFT C of G. Never noticed it on the 737, used to happen a bit on 767-200 a bit.

[hamilton]

I agree with dream land...it happen same a couple of time on dc10....just avoid still pulling nose up during latest moments beofre touchdown....but mine doen t want be any kind of suggestion of course.
Happy landings

[OscarYankee]

In my experience not an unusual event at all, although surprised me on the first few landings. Quickly learned not to add additional backpressure upon touchdown, or even release it slightly, untill the nose starts to drop. Being too fast to counter the dropping nose, can result in a unwanted pitch up...

[OutOfRunWay]

To A320 Drivers

Didn't this use to be a particular problem with the earlier A320s landing with CONF FULL?

I seem to recall the LH A320 runway overshoot in warsaw was in part attributed to them landing with Conf 3 (A SOP appearantly) to avoid spontaneous pitching up.

Anyone remember and care to comment?

OORW

[Centaurus]

Will sometimes happen on touchdown because thrust levers not fully closed and significant thrust vertical vector still in place. Accentuated with spoiler operation.

[Artie Fufkin]

Thanks for the responses.

Seems to be a concensus that autobrakes will help (not entirely sure but I think BOAC is correct; we normally use autobrakes but I don't think I did on these landings).

How/ why do autobrakes help arrest an uncommanded nose up pitch on touchdown?

[SNS3Guppy]

I'm not sure that it's uncommanded; if your nose is pitching due to autospoiler deployment, the pitch has been commanded. It's responding to an aerodynamic change. You may not have moved the stick or yoke, but the flight controls (spoilers) have moved, and so has the airflow about the horizontal stab and the downwash from the wing, as a result.

Why will application of brakes help? The pivot point for the aircraft upon touchdown becomes the main landing gear, and unless your CG is aft of the gear the airplane pitches down as braking is applied to the gear...of at least the upward pitching moment is reduced. How much depends on your CG, the amount of pitching moment, the autobrake (or your own use of brakes, as the case may be) setting, runway condition, etc.

First and foremost, the control for whether pitch attitude increases, decreases, or is forced to remain the same rests in your hands, not in the autobrakes or speed brake handle. Make the airplane do what you want it to do.

[World of Tweed]

767 has significant different feel during de-rotation with auto and manual speedbrake.

I was told on line training that if the auto speedbrake was inop to brief the captain to only deploy them once the de-rotation was complete or assured. The spoiler deployment scheduling is different and far more severe in manual than auto mode and hence the pitch up is more marked and on a light 762 could be quite interesting.... like potential tailstrike interesting. Particularly at slightly higher body angle, smooth, non-boeing, pissing on velvet touchdowns.

[XPMorten]

If I recal correct, deployment of spoilers on touchdown will move the
center of lift forward. This is why some acf like the B757
have a delay of 1,25 sec on panels #2 & 3 to prevent a pitch up.

http://www.flightlevel350.com/Aircra...ideo-9798.html

M

[westinghouse]

interesting.

we had a 320 scraping the tail after landing.
the touch down was normal. only one reverser was available and on selection the acft started to pitch up.
they pushed the nose down and deselected the reverse. at the gate the cabin crew at the aft reported they had heard a scraping noise.
airbus had an inquiry and no proper explanation was given.they stated an uncommanded pitch up occured. they are still looking into the matter.

any ideas guys?

[Dream Land]

Without all the parameters it's hard to say, but I prefer to make the actual touch down during de-rotation rather than the hold off technique, if you start the maneuver a bit too early, you will end up nose high and low airspeed, only one reverser opening and at the same time spoiler deployment, hard to control the pitch up tendency. This is another reason why I land with my feet high on the rudders, if this occurs on the A320 a bit of brake will help, if your heels are on the floor it's not an option.

[SNS3Guppy]

any ideas guys?

Pilots who let the airplane fly them, instead of the other way around.