747 "Wheely"

[anotherglassofwine]

A friend sent me this link, but as a lowly PPL I couldn't provide an answer ..

Why does the pilot flying leave the nose up for so long here?

Aviation Video: Boeing 747-200F - Air Atlanta Europe (http://www.flightlevel350.com/Aircraft_Boeing_747-200F-Airline_Air_Atlanta_Europe_Aviation_Video-16301.html)

Thanks
AGOW

[anotherglassofwine]

SloppyJoe - thank you for a most unhelpful reply.

Honestly who cares, it landed, it did not crash,

First of all - I care, hence the post. I was merely curious.
I didn't question in my post whether it crashed or if it was unsafe I was just curious to establish whether there may have been a reason for it.
If there is not, then a simple - "he just held it off for longer than normal" would have sufficed.

Take a chill pill ...

[shroom]

Wow, the poster above is a real jacka$$.

While it is normally a good idea in the 747 to smoothly "fly" the nose onto the ground after landing, some pilots for whatever reason like to hold the nose off occasionally. This is theoretically for "aerodynamic braking," but any text about jet flying will tell you that you should get everything on the ground as soon as possible (smoothly) to take advantage of all available resources (thrust reverse, anti-skid, spoilers, etc.) Many aircraft need to be flown onto the ground (see the 727) and reward a firm touchdown, rather than trying to "hold it off" and grease a landing. With a max landing weight of around 630 thousand pounds, the concern with a classic series 747 is getting it stopped.

Note that in the video only the inboard engines are in reverse. It is possible that one or more reversers were inop, thus the pilot thought s/he could help the landing distance by taking advantage of the aforementioned "aerodynamic braking."

Hope that's helpful, unlike the smarta$$ reply above.

[Capetonian]

Is it also possible that he thought there may have been a problem with the nosewheel assembly or tyres, and wanted to hold it off for as long as possible whilst bleeding off speed?

[Skipness One Echo]

It's an old school trick to slow the aircraft, have seen it a few times on the B747, mainly on cargo aircraft.

[anotherglassofwine]

Excellent, thanks all for the mature replies.

I certainly think it looks impressive :ok:

AGOW

[PPRuNe Pop]

Sloppy Joe made a sloppy reply. But then he never was a spotter was he? Went stright in to flying without one piece of airport curiosity....................

The three answers are equally as good as each other. I have 'used' an aircraft's aerodynamics to slow down and it is very common.

Generally, we have the full benefit of many FD guys and girls on this forum who are more than eager to respond to questions like this.

PPP

[con-pilot]

The only time I used to keep the nose gear off the ground on landing for any period of time in the 727, was on long runways when I would be exiting the runway at the far end or near it and with light wind conditions. The main reason for me doing that was, well, it was fun.

When landing on short runways I got the nose gear on the ground as fast and smoothly as possible while applying the brakes to maximum. Also it needs to be noted that the wing spoilers are not fully effective until the nose wheel is firmly on the ground.

[forget]

The Vulcan used aerodynamic braking to very good effect. An early 60's Mod introduced a small lever at the back end. This operated micro-switches which controlled two lights on the captain's glareshield. Pull back until one light came on. If two lights came on, ease off.

YouTube - ‪RAF Greenham Common Air Tattoo 1983 ii‬‎ (http://www.youtube.com/watch?v=e02U0Uh3MUY)

[Intruder]

Aerodynamic braking is NOT a recommended technique in the 747. There is too much likelihood of a tail strike if overdone. Besides, you want as much weight on the main gear as possible to help in braking. Crosswind controlability could also be an issue.

[Sygyzy]

To add to Intruder''s accurate comments:

You will find if you hold the nose up for too long that you'll run out of aerodynamic control of the tail surface (elevators) and the nose will thump down with a terrifying noise.

It's no fun to be pulling back on the control column mightilywhen this happens but having the nose-with you in it-come crashing to the runway like some macabre roller coaster ride.

I believe the last a/c where aerodynamic braking was suggested/recommended was the DH Comet. No reverse available from those engines? Not sure.

S

[dixi188]

I don't know what signals the engines to ground idle on the B747 but on the A300-B4 the engines will not go to ground idle until the nosewheel is on the ground.

A few years ago the reversers were locked out pending a modification. A Capt. I was flying with said he would hold the nose off to use aerodynamic braking. I pointed out that at flight idle there's almost 5000 lbs of thrust per engine pushing us forward, whereas at ground idle there is less than 2000 lbs of thrust so putting the nose down early would be a good idea.
He agreed.

If the 747 is similar then those 2 engines not in reverse would probably cancel out any aerodynamic braking effect. ( same engine type I think).

[parabellum]

When I did a course at Boeing they told us that, apart from large delta wing a/c and a/c with wings like the Comet, there was no benefit to trying for aerodynamic braking, fly the nose smoothly on ASP.

[NWA SLF]

Isn't this runway at Schipol the far north runway that is always lined with spectators? Some holidays it seems like half the Amsterdam population is lined up along the road watching the big boys take off (when I have landed or taken off on this runway it is almost always on an A-330 or larger). Could the crew just be putting on a show for the crowd?

[SNS3Guppy]

At amsterdam, in particular, most of the time one has a very long taxi to get either to parking, or to the runway. In the 747, when heavy, the taxi distance can equate to very hot wheels, even without brake useage (the weight of the airplane on the wheels, during taxi, causes the wheel and brake assemblies to heat up). If the airplane is going to be turned around quickly, then anything that can be done to reduce brake temperatures is a plus.

One technique that's often used is to use minimum braking. Generally this is done with reverse, as landing in autobrakes will reduce the amount of brake useage when reverse is employed. The airplane only cares about the rate at which it slows down, and doesn't care what's slowing it down; autobrake settings reduce brake application if other means of slowing the aircraft down are employed.

Some pilots will land with autobrakes and shut them off once the spoilers are deployed and reversers are out, preferring to wait until late in the roll to apply brakes (assuming sufficient runway).

If the brakes aren't in use, then getting those nose down won't be of any benefit. Generally on landing, the ground spoilers deploy, killing lift and putting more weight on the wheels. Lowering the nosewheel to the runway also reduces lift and puts weight on the wheels, for more effective braking. If one isn't doing a lot of braking, but is instead relying on reverse and some aerodynamic braking, then this explains the rollout on the video.

In the case of no braking, any aerodynamic effect achieved from holding the nose off is beneficial, even if it's minimal. You can see in the video that the crew deploys spoilers immediately on touchdown (autospoilers), and then applies reverse, and rolls out in reverse with the nose off.

The hazard of doing so, of course, is that directional control is improved with the nosewheel on the ground, and reduced with it in the air. At higher speeds with ample aerodynamic authority for the rudder, this isn't a problem, but generally we try to get the nosewheel on the ground earlier. Deploying reversers with the nose in the air isn't a problem so long as everything deploys evenly and there's not a strong crosswind, and all the engines spool up evenly. If there's a directional problem or challenge, however, control authority is much better with the nosewheel on the ground, which is part of the reason that you're probably used to seeing it lowered earlier in the landing roll.

[Hydromet]

Many years ago I was SLF on a 727 out of Adelaide which had a nosegear problem after takeoff. Found out later that it wouldn't retract properly, then stayed red when they tried to extend. The return landing was the smoothest I can remember, right on the piano keys, but the a/c was almost stopped when the nosegear finally touched (very gently).

[Swedish Steve]

Many years ago (around 1980), LTU operated Tristars from the Maldives to Germany with a fuel stop in BAH. We refuelled it there. The ground time was only about 30 mins, (on the gate for 20mins) as the same crew operated through. We had two bowsers ready, pax stayed on board, no catering, no defects!!
They landed nose high, and left it there all the way down the runway. When it arrived on the gate the brakes were icy cold. So no delays with brake cooling times.

[Intruder]

With a long enough runway, you can stop an airplane with minimal braking even without aero braking. At Andersen AFB, Guam, for example, I've stopped a 747 Classic several times with only idle reverse and no brakes until testing them near the end.

[donnlass]

For whatever reasons pilots do it, its elegant and lovely to see. Love watching the A330's do it at MAN.

[Davidsoffice]

I remember seeing an Islander land at Manchester, 24, taxi off on three wheels but then doing a 'wheely' past piers A and B over to the Fairey hangar. Impressive! Humber Airways if memory serves...must have been about '74/'75.