PDA

View Full Version : Keeping the nosewheel up


GearDown&Locked
3rd Mar 2004, 06:19
Quite often, I see some crews running down the runway with the a/c's nosewheel up long after the touchdown, and droping it right before vacating (mainly A319's, 20's); alltough it looks cool, and it seems to display some high handling habilities, but is that really necessary? is that safe??

GDL

BlueEagle
3rd Mar 2004, 06:39
I was taught that it is not good flying practise to hold the nosewheel off, for a number of reasons:

1. Boeing teach that as soon as the main gear is down the nose gear should be positively 'flown on' to the runway, i.e. a Small check forward to achieve a gentle contact. The benefits of aerodynamic breaking are, they say, far outweighed by the benefits of the increased drag from the nose-wheels and the reverse thrust vector is more effective the more horizontal it is as it is directly opposing forward speed and not at an angle.

2. Less chance of a tail strike by putting the nose down immediately after the main gear, particularly if you get caught by even a small gust and you only have minimal elevator control.

3. Unless the final touch down of the nose wheel is very carefully controlled then holding it off can cause it to eventually thump/drop down when elevator control is lost. Continual 'thumping' not good for the engineering! By putting it down when elevator control is still very effective a gentle contact can be achieved.

The above are offered as discussion points as I know there are a variety of theories out there! ;)

A_plata
3rd Mar 2004, 09:28
As BlueEagle said Boeing strongly recommends that the airplane nose must be "flown" into the runway, not only for the reason that he has mention, being the possibility of a hard nose landing gear contact with the runway, five years ago there was a safety seminar conduct at our airline and the Boeing guys shows us a couple of pictures of nose landing gear struck into the fusale and a 767 with the whole fuselage bended behind the nose landing gear.
The reason being that as you lose speed rapidly the elevator not have enough authority to reduce the rate at which the nose goes down, with that kind of results.:ok:

LEM
3rd Mar 2004, 17:06
It's obviously done for fun, not for a technical reason.

I did that only a very few times, and so probably do the guys you are referring to.

Under certain particular conditions (loooong runway, light weight, rear CG) sometimes you do that just for fun, because you feel it's almost coming by itself... I mean, you didn't plan to do it, but decide on the spot.
You hold it up longer than normal until you feel it's time to drop it safely.
Yes it takes some degree of skill.

Once again, we all agree it's not good practice routinely , it's only done for fun when the conditions permit.

One day I did that in EDDM, and the controller told us "Nice wheeling!".
It was the first time I had heard such a term.

Another theory I heard long ago in darkest Africa, after I saw DC8s doing that routinely, was that you save a little bit the nosewheel tires life.
I didn't consider it worth adding that technique to my background, though....:hmm:

keithl
3rd Mar 2004, 18:48
In the context of the question (A319, 20, etc) I'm not qualified to disagree. I would, however, point out that holding the nosewheel off is not intrinsically good/bad. It is type specific.

In some older and some military types, without reversers, it would be done to save a brake chute, or brakes, or in case of hydraulic failure. I used it in that way some - no, many - years ago in a Canberra with no brakes (or flaps) and of course in order to do that, it had to be practiced.

FlyingForFun
3rd Mar 2004, 20:06
I hope this isn't too off-topic.... but what do people do regarding lowering the tailwheel to the ground after a wheel landing in a tail-dragger?

When I was taught to do wheel landings, the instructors I flew with suggested that the stick should be moved gradually forward until full foward deflection is reached, and then held there until the tailwheel drops, at which point the stick is moved fully aft.

I found that this gave a very uncomfortable bump as the elevator looses effectiveness - in exactly the same as you guys are reporting that Beoing say holding the nosewheel off gives a nasty bump in their airliners - and that if I moved the stick gradually aft immediately after it reached full forward deflection, the result was much more pleasant. Of course this will be type-specific - I was flying a PA18, but interested to hear what other taildragger pilots do on all types (including the old airliners).

FFF
---------------

quid
3rd Mar 2004, 22:08
Many years ago I saw some guys do that and thought it was "cool". One day I tried it myself, and after I lost rudder effectivness, the slight crosswind got me too close to the runway edge. Later, I wondered what I would have done if a main gear tire(s) blew. Never again.

Like many of us, I was lucky and got away with lots of things before I "grew up".

BRAKES HOT
4th Mar 2004, 00:35
trying to hold the wheel off isn't cool, especially in big heavy aeroplanes. Better to fly it on 'cos sooner or later it's gonna decide to derotate itself anyway and it won't be funny. Especially if it's because the autobrake has just kicked in :}

Flight Safety
4th Mar 2004, 03:02
I'm with quid, nose wheel steering needs to be effective before the rudder looses authority, especially in crosswinds.

VP TAA
6th Mar 2004, 00:03
If the runway remaining is long , there is no crosswind , the touchdown was nice and smooth , you dont want to wake the passengers and the aircraft is in good shape , then its OK to use the aerodynamic drag to slow the aircraft down , but put the nose wheel on before you run out of elevator efectiveness . Remember if anything goes wrong you will take all the blame . No aircraft manufacturer I know of recomends this technique . But it looks gooood . Some passengers panic because they dont feel the deceleration they are accustomed to and that may destroy any good feeling they may have had about the landing . So all in all I say get in the habit of getting the nose wheel on asap smoothly . One day in a long aeroplane and wet runway with a stiff crosswind you will pay the price or come close to if you dont . You gain directional control, reverse is most effective, the wing tips are further from the runway ie if there is any rolling it will mininise the tendency in swept wing aircraft for the wing tips to touch the runway , and maximum braking effectiveness will be achived with the nosewheel on the ground .
Regeards
VP TAA

GreenArc
6th Mar 2004, 00:19
If memory serves, doesn't holding the nose off in the A320 prevent the stabilizer trim from resetting? I believe you need to land the nose within a few seconds of the mains in order to trigger the reset.

Otherwise, have fun, but be careful ;)

GreenArc

NSEU
6th Mar 2004, 06:37
It was found, long ago, that on the 747, that aerodynamic braking by keeping the nose up is not as effective as putting the nose down and letting the spoilers do their job... i.e. putting more weight on the main gear, increasing wheel braking effectiveness. With the nose high in the air, I gather that the spoilers are being sheilded from the airflow.

This is mentioned in our AOM.

I'm very surprised to hear that some pilots are still using the nose-up technique.

Putting the nosewheel on the ground also gives you... guess what... nosewheel steering. Sounds like a good thing to me ;)

Rgds.
NSEU

GearDown&Locked
6th Mar 2004, 08:44
Obviously the guys i've referred to previously do it for fun, it looks really cool, and they seem to let the nose drop smoothly as they loose speed, so no stress on the front gear.

On the other hand, I've seen an md-80 from a well known mediterranean company, do the opposite kind of landing, i.e. banging the runway, both main and front gears. Lot of spilled coffee in the back. Good tyres though... :} :yuk: :}

SeldomFixit
6th Mar 2004, 17:49
GreenArc - generally in Airbusses, there is a pitch element in the stab ground setting logic that is satisfied by NLG on gnd.

shuttlebus
7th Mar 2004, 01:09
GreenArc, SeldomFixit,

I seem to remember reading that if the nosewheel was not down 30 seconds after the mains, the stab trim would "hang" at the touchdown setting and only maint. could reset it to zero...

Don't remember where I read it though :confused: :confused: :confused:

You could try over on www.airbusdriver.net or search the threads for A320...

Regards,

Shuttlebus