B777 After Thumping Checks...help!

[Shintaro Abe]

By force of circumstance, I am now a B777 driver after some ten over years on the B744. Without any intention at self-aggrandizement, almost all of my B744 landings had been reasonably smooth with lots of " greasers " even in challenging wind conditions.

Now, after some 2 years on the T-7, I could count the number of decent landings in one hand. I thought the B777 is a great aircraft but I find it wobbly and not speed stable at all in gusty crosswind conditions compared to the B744. The ground spoilers are real " spoilers " as far as smooth landings are concerned; derotation after touchdown is another bitch, it's mostly a crunching thump...it's almost always " after thumping checks " after clearing the runway.

Am I too spoilt after a decade on the " Queen "? It's getting annoying as T-7 colleagues ( who have never flown the Queen ) swear that this 2 dong tube is a super duper contraption. Mind you, I did manage a nice one during a rather nasty crosswind, but the next few ones after that were real disasters. There must be some real super duper B777 aces here on Pprune who can give some good pointers to an old dog here.

[Ericfaint]

I have just done the opposite; 2 years ago I transitioned from the triple to the Queen. The Queen is just awesome, she is just so speed stable on takeoffs and landings. I must say I make my smoothest landings right on the spot on the B744. On the B777, I dreaded the times in gusty crosswinds when I did not decrab completely ending up with some twisty crunchers. The triple wheel bogies on the T-7 are certainly very intolerant of any residual crab especially in strong crosswinds on dry runways. One of my landings seemed particularly bad that we wrote it up for a hard landing check...it was a false alarm. The guys at FOQA pulled up the QAR readings which revealed a 1.55g vertically and a lateral g of 0.19, well within limits. However it felt so bad in the cockpit and the hostess gave us the funny looks!

An old timer explained that the Queen has excellent wing loading due to the 2 outboard engines, lending stability. Her wing/body gear combination and geometry plus the massive ground effect of the flaps gives her excellent touchdown characteristics. The 2 engine T-7 lacks speed stability of lateral wing loading of an outboard engine; the B777 wing loses a lot of lift during an abrupt decrabbing manoeuvre leading to heavy touchdown. Furthermore the long wheel base with triple in line wheels causes a sort of twisting moment ( sorry I lack the vocabulary ) which exacerbates the effects of the heavier touchdown to make it all seem a very bad landing if the decrab is not fully completed to align with the runway. This may not be technically correct, but that's the explanation I got. Hope this helps!

[Notso Fantastic]

Ah the 744- such a wonderful machine! I used to be able to do many touchdowns where the only way you knew you'd contacted Earth was the activation of the speedbrake lever. So nice to handle in gusty winds, strong crosswinds, heavy weight- Boeing did such a good job refining the 747, especially that shock absorbed undercarriage, to sheer perfection! Can't help with your query at all, but thankyou for taking me back! Apart from the VC10, it's the only aeroplane I've ever really missed (followed by the B58 Baron)!

[rudderrudderrat]

Hi Shintaro Abe,

I never flew the 777 (BiStar), but you say your X wind landings are greasers. If you touch down on one gear first - then the ground spoilers behave differently.

Suggest you "invent" a cross wind next time (if one is not present) and touch down on L / R gear first.

[EGGW]

To be honest, the older -200,200ER and -300s are somewhat random in making a smooth arrival, the -300 being the most random.
The rest, 200LR, 200F and 300ER are gairly straight forward landing. I have 5000+ hrs on the T7.

EGGW.

[haughtney1]

Shintaro Abe, I'd say you've been spoilt.
I've been on the 777 for the last 2 years, and for context the 757/767 for 6 years before that.
I fly every variant of the 777, and the same technique works equally as well on all of them, in a gusty crosswind I always touch down one wheel first, i.e. decrab then a little upwind aileron and rudder which results in a nice kiss with the tarmac. As for the de-rotation, that's more finesse than anything else:cool:

[5LY]

Sounds like not fully decrabbing is part of your problem. Start decrabbing a bit earlier. The autopilot does it at 500. You don't have to start that early, but the stronger the x-wind the earlier I do it. That gives time for all of the other variables to adjust so you're not fallijng from grace at 10 feet. Add another 5 knots to your bug speed. This also helps to counter the loss of lift during decrabbing. With respect to derotation after touch down, you have to snatch it back smartly as soon as you see it starting to pitch down, but be carefull not to do it too early or you can have the opppsite efffect. It does have a tendency to pitch up with reverse selection. Lastly, don't stop flying your a/c just because you're on the ground. If you release your cross control imputs too soon your wing wants to come up and now your playing catch up at 170 knots.

[FullWings]

I find I get the best landings on the 777 by touching down with a slight rate of descent, rather than trying to arrest it completely, the idea being to get the oleo travel used up before the spoilers deploy.

The triple is a very easy machine to 'overflare', in that not a lot happens at 25-30R when the manoeuvre begins, so you instinctively increase the pitch which leads to a low flypast then a sort of flop onto the runway. A better method is to make the initial flare, hold it, then as the wing goes seriously into ground effect the descent rate will almost all come off, leading to a nice touchdown in the right place. The speed's got to be in the ballpark for this to work, though.

I find the 777 very good in crosswinds but if you don't get all the drift off on a dry runway (by whatever method), it will do a sort of shimmying shake on touchdown. This actually feels worse than it is and it's not so noticeable in the cabin.

Coming in faster isn't going to help much, I'd have thought, especially if the autothrottle is in. You still need to touchdown and extra speed will increase the chance of floating down the tarmac unnecessarily.

Landing with one wing (into-wind, preferably) down, even a little, makes for a smoother touchdown. Even better when the auto-speedbrake is U/S and you just deploy them gently after contact.

[Three Wire]

I second what the previous poster said.

1. get the seat position right.

2. Use the FBW to help you.

3. Do not go for a zero sink rate landing.

Check the sink rate at the flare point and let it settle.

Land it like a DC3 - one wheel first in a x-wind and then push it straight, then aileron into wind. The rudder is big and is a speed brake in a xwind decrab. A little extra speed helps the aeroplane and you, the autothrottle takes care of the thrust.

it is a numbers aircraft, not a finesse aircraft.

3W

[cosmo kramer]

I am flying 737, but maybe I can offer some general pointers?

If you are having a bad stretch, the result may be that on every subsequent landing you are "trying too hard".

Unconsciously, you may be trying to take every input available in order to find that "magic tool" that will help to smooth things out. In doing so your attention may be divided between outside and instruments, and your eyes racing around looking at different places to take in all input. All in the most critical seconds before touchdown, where your eyes should be one place only - outside!

Forget everything you tried so far and start over. When it comes to landing, every aircraft is an aircraft, no matter what they wrote on the outside, and what boxes they put in the E&E compartment. Only the size and timing of your inputs may vary, but the technique is the same. Basically it's all about bringing the thrust to idle and the raising the nose and nothing else.


Some general tips, that works for all aircrafts, partly copied from another post of mine on landing the 737:

1) Fix the runway aiming point markers in the window and only look in to check speed.

If you fly the ILS, eyes inside, down to last 100 feet and subsequently have to make larger variations to your sink rate when looking outside, it's difficult to get consistency in your landings.

Ideally your eyes should primarily be looking outside from the last 500 feet, or with suitable visual references latest, until touchdown. In good weather I would recommend from 500 feet (or even earlier when you see the aim-point) to gradually switch you path guidance from the ILS to fixing the aim-point, and from 300 feet on completely stop looking at the instruments, except to check speed.

The glideslope, PAPI and Touchdown markings are often not co-located, hence all this information may unstabilize the path at the last moment if switching focus between them in the expectation that it's possible to get them all to magically align. Actually they are all useless information, compared to the much more precise cues one can obtain from just fixating the aim-point in the window. Sticking to one cue, makes sure that the path and vertical speed remain the same.

Being where you want to be in a stabile state is the key to a greaser. If you were used to a very stabile aircraft you may not have had to work very hard on that in the past.

2) When reaching the recommended flare point for a 777, bring the thrust back to idle (altitude pr. 777 FCTM). On the 737 a lot of people use a technique contrary to the recommendations in the FCTM (delayed thrust reduction) usually with poor results and longer landing than necessary.

3) Switch view to end of runway. Don't look at the touchdown zone and don't let your eyes wonder inside to the instruments.

4) Use your vision to judge the vertical speed and adjust input as necessary. The perspective by looking at the far end of the runway, will give you the optimum premises for evaluating you vertical speed.

6) Use your feet to align the aircraft with the direction of travel. Even the lowest vertical speed will feel like a ****ty landing if you come down sideways (737NG is equally intolerant to drift). Compensation for loss of lift should now be easy, since you are already looking at the far end of the runway.

7) Let it come down. Don't hold it off, like some previous posters already wrote.

Most "firm" arrivals are caused by not looking where you are supposed to… out the window!

Make sure you seat position is correct with regards to recommended eye reference position. Make sure you are not sitting too low. That will make it all easier.

My take is, that your mistake is being too much inside the cockpit. Being primarily outside already from the last 500 feet, takes out the surprises when reaching the flare point. And when reaching the flare point immediately switch all attention outside, bring the thrust back as recommended in your FCTM, and and make sure that your eyes are looking/your undivided attention is at the far end of the runway.

[fantom]

Dear me, this is so easy: just try an Airbus.

[nitpicker330]

Yes exactly, never had trouble landing the mighty tripple. Now the Bus on the other hand!!! Damn gear tilt!! :{

Best A/C to land: 747, not called the queen of the skies for nothing :ok:
Second best: 777-300ER, semi levered gear makes it almost as good as the 74
Worst: do I need to say it?

[EW73]

Well, that IS a surprise coming from you Fantom...

and your B727-200 landings were so consistently pretty good if I remember a few years back...(now that IS a difficult airplane to land successfully)

how things have changed...

EW73 :ooh:

[JammedStab]

your B727-200 landings were so consistently pretty good if I remember a few years back...(now that IS a difficult airplane to land successfully)





Not that bad really. Chop the thrust at about 20 feet while checking back for the flare, then relax forward. Got all of my jet super smooth ones on the 727-200. 737-200, not one greaser in almost 300 flight hours.

Hope to find out about the 747 soon.

[anne747380]

B777-300 weird hard bouncy landing - YouTube