B777 Cross Wind Landings

[yelena]

I have just transitioned from the B767 to the B777 about a year ago. Cross wind landings for the B767 seemed much simpler than the B777. I was taught the decrabbing method during the flare but it is fairly to get the technique spot on...mostly ending up in what seem to be crunchers. Luckily, even when logged into the technical log as suspected hard landings but thankfully the engineering division came back with negative QAR data which indicated any hard landings beyond the limit. However from the cockpit, the landings felt terrible! This is especially so if I couldn't decrab fully before touchdown. There was some residual crab angle at touchdown which was fully corrected after touchdown......the feeling I felt in the cockpit was a terrible sensation of a bad landing! However the engineering guys said that the verical g was only 1.58g and the side g was well within limits. Then why did it feel like an absolute cruncher? Hopin to be enlightened by the B777 gurus out there!

[Spooky 2]

Suggest yoy Google You Tube and ask for Boeig Crosswind Landing Tests. Good visual presenation and I think it will lead you to more info.

[bakutteh]

Decrabbing fully during the flare is nice and dandy in steady crosswinds but fairly difficult to perfect in the real world with variable gusty crosswind on a hot day. This especially so when you only encounter such occasions infrequently and get to practise once annually on the simulator which probably cannot replicate real world environmental conditions during a hot gusty crosswindy day.

I would suggest crabbing down to about 500 ft AGL and then decrab early transitioning to a landing with the side slip method, touching down with the upwind gear first when the crosswind is 25kts or less. Above 25 kts, just bear with all the imperfections of an untidy decrabbing during the flare. Just bear in mind that during the decrab during the flare, you lose quite a bit of lift and would probably need to pitch up more, override the auto- retardation of the thrust levers just a tad to prevent a cruncher. Please understand I am no B777 guru; I left the B777 several years ago and I survived enough years on line operations on that equipment to share something here.

[Vel Paar]

Sigh, I have done a few crunchers myself. Luckily nothing above the limits as borne out by the QAR readings. Well yelena, take heart as you will improve with time. Like bakutteh said, it's pretty hard to get the decrab during flare technique right. I have overdone it a couple of times ending up with the nose pointing a tad to the downwind side with an awful sensation upon touchdown. I think bakutteh suggestion to follow the autopilot technique of decrabbing early and then sideslip to touchdown works well. I have never had a crosswind exceeding 25 kts, so I am not sure whether this technique work well or not in this case.

[Molokai]

There is a gentleman somewhere in the Lion City by the name Old Smokey who probably can share with you guys his immense experience on the B777. I believe he has written about his misgivings about landing without decrabbing on the B777 eventhough this has been demonstrated by Boeing test pilots.

[FullWings]

The T7 undercarriage has rear steerable wheels which will castor to maintain airplane ground track upon touchdown when the aircraft nose is not fully aligned with the runway.

That's news to me... I do know that the 777 has the ability to allow the 3rd pair of wheels to unlock during taxiing to avoid tyre scrubbing in tight radius turns. If these are not locked straight before takeoff (an automatic function) it will generate a config warning.

Personally, I find the triple very good in crosswinds. Up to 25kts I use wing down and over that I combine wing down with either landing with the rest of the drift still on, especially if wet, or an extra little decrab close to touchdown.

[Babablackship]

Old Smokey, are you there?
There is a gentleman somewhere in the Lion City by the name Old Smokey who probably can share with you guys his immense experience on the B777. I believe he has written about his misgivings about landing without decrabbing on the B777 eventhough this has been demonstrated by Boeing test pilots

Old Smokey is probably too busy or disinclined to post here lest some smart alecks hijack this thread with the flt sim logic.

[bauduin_alex]

Next time you'll go in the box ask someone to do the landing and call up the flight control synoptic page and observe surfaces deflection during the decrabing. Moving the wheel to decrab will ask for flight spoilers to go up and increase drag/reduce lift = sink rate increased. I've tried at 400 feet also but then it sinks if you're not proactive on the throttle. AT is programmed to respond fast to wind gust only, PFC and LAM will help you for pitch, not for speed. In both cases a small application of power smoothen the thing.
My best technique so far, scary for people in the back (I imagine because I'm only flying the box) is to kick the rudder at 20 or so. By the time you ve finished compensating in roll with wheel the speedbrake will be already out and at least one of the mains on ground.

One thing to know about the box and wet runway. We can tune the water depth for the airline it is part of subjective evaluation of the box. So it is different from one box to an other if not in the same company. You might find it easier on one box and terribly hard on the other. Regulation states 3mm or less for water (meaning 1,2 or 2.99 are acceptable values).
Happy landings.

[B777Heavy]

The winglow method works better on the B777. Try doing an autoland (if you can, or in the sim) with crosswind and see how George puts her down. Long story short, the A/P, does a fantastic wing-low.

[rudderrudderrat]

In strong crosswinds - I prefer a combination of partial decrab (within 5 degs of runway heading ) & one wing low - during the flare.

Airbus does a good presentation explaining the loads on the gear / saturation of flight controls, etc. (around page 6) here (http://www.airbus.com/store/mm_repository/safety_library_items/att00007639/media_object_file_FLT_OPS-LAND-SEQ05.pdf)

Anybody know of one from Boeing?

[Sargeant Snorkel]

In very strong crosswinds above 25kts, a combination of the wing low and decrab method works. Somewhwere in the B777 FCTM, it is recommended that some crab angle be maintained until touchdown on dry runways with very strong crosswinds. However when one straightens the nose after touchdown with the remaining crab the sensation felt is quite unpleasant leading to some dumbos to think that it is a hard or bad landing.

Many years ago a Boeing company test pilot explained to me that because of the long wheel truck, touching down on the rear wheels with a crab followed by a quick straightening of the nose will induce a " twisting " moment which make it seem like a bad landing. I have left the B777 fleet but do remember occasions like these. Pilots who have never physically flown a B777 do not appreciate this characteristic of the undercarriage ith a long wheel truck.

[Nil defects]

Have done lots of landings in 777 in up to 40kts crosswind (and more in the sim with up to 50kts). Is easiest plane to land ever built!

As per the FCTM, I use the crab all the way to flare. During flare push nose around as per normal techniques and opposite aileron.

Most common error is that guys let the nose drop and aircraft descends onto the runway before fully decrabbed. Yes, you don't want to float past the touchdown zone but a little hold off till straight, then release back pressure, if required, to let it settle on works well. (and of course as others have mentioned, it doesn't matter if it touches down before full decrab, in fact above 31kts Boeing recommend it)

Have tried it also carrying a few extra knots. But even 2-3 kts more than Vref+5 will cause a longer float so even in gusty crosswind is not really required.

Keep it simple - it works.

[gleneagles]

Wrong! The easiest plane to land is the B747 classic followed by the B744. Flown all 3 types and the t7 is nothing compared to both the B74s.

Wow, surprising that your company allows landing on the T7 above 38kts. Must have empolyed only super pilots! Our outfit design policies for the AVERAGE pilots and do not aloow landing in crosswinds above Boeing demonstrated figures.:suspect:

[SpaceNeedle]

A former Alteon guy told me how an anal retentive colleague of his failed a pilot who used a combined decrab and wing low landing method in the simulator; apparently it wasn't a very tidy landing but no crash or drift off. This guy mentioned that he just couldn't understand how that colleague could have failed the checkee as the simulator then didn't have the fidelity anywhere close to that of an actual aircraft.

[Nil defects]

No super pilots here, just following our published crosswind limitations:

DRY 40 kts
Slippery 35 kts
Contam. 20kts

Ref FCOM L.10.2

[ghw78]

From Mr Boeings B777 Flight Crew Training Manual

Landing Crosswind guidance
Dry 45 knots, Wet 40 Knots
Ref Page 6.37

T/O Cross wind guidance
Dry/Wet 40 Knots (gets a bit complex at varying weights and MACs)
Ref page 3.12

It also states that these figures are provided for individual airlines to establish

THEIR OWN CROSSWIND LIMITS

[woodyspooney]

Flew the triple for some 8 years, had many wonderful crosswind landings decrabbing during the flare at close to maximum allowable crosswinds. Always nice smooth touchdowns; in the sim, had the instructors crank up the crosswinds to 55 kts.........no problem! I was beginning to think that the B777 IS REALLY A WONDER ( or was I a true boy wonder?! ) until one hot, humid and gusty day ( a typhoon wasn't far away ) at MNL. A bumpy ride with crosswinds about 28 kts.....well a piece of cake I thought with my previous impeccable record of tackling crosswinds more than that. Down to a flare at 30 feet RA and a cool left rudder pressure and right aileron input to align with the runway. In a split second the wings went wiggy waggy and we crunched onto the runway in a most awkward fashion. It really felt terrible and both of us at the pointy end really thought we had a collapsed gear! A call from the cabin indicated some O2 masks dropped. Drat, we really feared the worse. Never had a lousy landing on the triple before.

Seriously we asked tower if we still had the undercarriage intact; not to worry, all was fine. We wrote in a suspected hard landing in the tech log, the maintenance guys did their hard landing inspection. Nothing amiss. The maintenance control guys pulled out the QAR data......no side loads beyond limits and maximum vertical G was 1.51. What a relief but it really felt like such a lousy landing!

Over the next few times with quite a bit of crosswind I was very cautious and wary but most of the subsequent landings turned out great. Then one lousy afternoon in CJU a similar thing happened but not as bad as the one in MNL. Then I never had any more of such crunchers again. I am no ace but I still cannot figure why. Nobody else could enligthen me since.

[BuzzBox]

In a split second the wings went wiggy waggy and we crunched onto the runway in a most awkward fashion.

Did you start using large, rapid aileron inputs when the wings went 'wiggy waggy' during the flare? If so, perhaps the resulting spoiler movement dumped all the lift, causing a crrrrrrrrruncher. I've seen it happen a couple of times while landing in turbulence. The 777's FBW ailerons are very responsive.

[woodyspooney]

I do not remember my aileron inputs that clearly during the first incident in MNL. However I do not normally induce PIOs or make any rapid alternating roll inputs. Having said that, I too suspected that the QAR probably might not have all data on the aileron/spoiler movements when the wings went wiggy waggy in the turbulent crosswinds. I did consider this to be the cause of the cruncher.

The FOQA guys vaguely told me something about the " gear approach " angle being increased suddenly. I did enquire if there were any rapid alternating rudder or aileron inputs indicated but they indicated in the negative. Hence I could not definitively pin point the actual dynamics which led to the cruncher.

Well I am retired now and do not really remember much about the full verbal report by the FOQA guys who had great difficulty articulating the " secret findings " in English ( English was not their first language ).

I have a better recollection of the second cruncher; the aileron inputs and rudder pressure were fairly gentle as far as I remember. As it wasn't that " disastrous" I did not file in any report, so no QAR or FOQA info.

I have come to realise that as always.........." on a one or two lousy day, anything can happen " is an axiom lurking somewhere out there. Bravo and good luck to all the aces, but the 2 crunchers proved a sky deity I ain't!

[Old Smokey]

Yeah, I'm still here, and still trying to work out how to consistantly do a good landing in the B777. The B777 is now my "high time" aircraft, and I'm still trying all of the good advice from fellow Prooners, Boeing, colleagues, and Boeing.

I can honestly say that I have never done a "bad" landing on the B777, but the "good" ones are few and far between. The majority are the usual shake shake shake as the main gear bogies touch down (impact?). At least I've worked out how to fly the nose-wheel on instead of trying to hold it off in a fruitless endeavour to soften it's impact:ok:

My personal theory is that the triple bogey main gear is very intolerant of ANY residual drift, no matter how small. Not experienced on other single and double bogey aircraft. On numerous occasions I've had the aircraft set up for what would be a "greaser" on any other aircraft, only to result in the B777 shake shake shake as the main gear bogies touch down.

My last landing was a very good one (the 1% probability), methinks I should retire now whilst the going is good. I'm due to commit aviation again tonight, I know already what the landing will be like (the 99% probability).

Ah well, practice makes perfect.:ugh:

[MrBernoulli]

At least I've worked out how to fly the nose-wheel on instead of trying to hold it off in a fruitless endeavour to soften it's impacthttp://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/thumbs.gifOh go on, do tell us what the magical solution is! It is something I tussle with now and again, too! :O

[Abbey Road]

SpaceNeedle,

Well done, for shooting yourself in the foot! In support of Nil defects, our 777s use the following limits:
Maximum crosswind, takeoff - dry: 40 knots
Maximum crosswind, takeoff - wet: 25 knots
Maximum crosswind, landing dry or wet: 40 knots
Maximum crosswind, takeoff and landing - icy, slush,standing water: 15 knots
:ok:

[Bolty McBolt]

Hi. The first is one of the 1% landings


YouTube - Korean Air Lines Boeing 777-2B5(ER) Heavy CrossWind Landing @NARITA RWY16R (http://www.youtube.com/watch?v=rLq-rchG-X8)

The second.


YouTube - Korean Air Boeing 777 A very bad landing!!! (http://www.youtube.com/watch?v=5q6rdBxDKu4&feature=related)

[kickapoo]

Hey, this look very much like some of my landings! Always waiting for the FOQA guys to call me out but those dreaded calls never came. So one fine day got up enough nerve and pestered the FOQA guys to checked out some of my untidy landings like the one above........they were untidy allright, but the FOQA guys assured me that nothing untoward happened; the aircrafts were fine and the bosses up the foodchain took them to be the lousy landings of lousy pilot on an equally lousy day. Only my pride went down the toilet.....................

[Vel Paar]

YouTube - Boeing 777 Crosswind Landing Cathay Pacific Hong Kong Kai Tak Airport ?? ???? (http://www.youtube.com/watch?v=dd9NM9vsGD8&feature=related)

This looks similar to one of my lousy landings. Tried to decrab and straighten the nose to align but somehow I ended up with something like this!. There were times I did a perfect decrab but something like this happened a couple of times. Like a former skipper of me told me; from flare height to touchdown is sometimes no man's territory.

[FullWings]

Some of my best landings, crosswind or not, have come from landing with a definite rate-of-descent on. I've found that if I try to reduce the ROD to zero as I touch down, the speedbrakes deploy and immediately drop the airframe the length of the oleos. Letting the aircraft settle onto the tarmac in a flared attitude seems to take up the slack in the legs before the lift dumping really takes effect: if you get it *just* right, the vertical component of the fuselage velocity reaches close to zero as you reach the limit of oleo compression and *stays there*.

In fact, if you just increase the pitch a few degs. at 25-30R and hold it, the aeroplane will do the rest. Funny old thing, that's what the manuals say!

[falconeasydriver]

I'm not sure why there seems to be any great mystery about x wind landing the 777. The same thing that works well on the 757, works on the 767, and certainly works on the 777.
Flare at about 30ish RA, thrust reduction as required, at the 10' call a gentle decrab with a bit of into wind aileron, works a treat everytime on 200 & 300 variants. There is no great mystery here, look at the far end of the runway (RVR permitting) and fly the aeroplane. A damn sight easier than a pitts or an extra.
I think some guys on here would benefit from 5 hours of circuits in an aeroplane with conventional undercart.

[bauduin_alex]

Space Needle,
If it was level D simulator then it is extremely close to the actual aircraft. Refer to PART 60 FAA for explanation about different levels of fidelity for simulators.

[ASRAAM]

Having observed a good number of cross wind landings in the sim and a/c I will offer my 2 pence worth.

Firstly, the simulator is generally a little less forgiving than the a/c, don't get too disheartended if the sim lands firmly.

I have traditionally, due to previous types used the crab technique until the flare. This works OK on the triple, but with only a little practice the wing down works better.

If the opportunity presents itself on your next sim cx, set the sim up to autoland in about 30kts across. The aircraft will start to decrab fairly early, a bit before most pilots who are advocates of this technique would do. At about 75r drop out the A/P and do your best to freeze the controls where they are. Flare slightly earlier than for a normal approach (the a/c is cross controlled and less efficient).

Once that works out OK, try pushing back the point at which the A/P is disconnected, once that works, start increasing the cross wind up to 40 kts.

You now know how to do the wing down in a 777!

Be aware though that the Boeing manual contains an advisory note that pure wing down above 34kts (I think, dont have the book to hand) results in degraded ground clearance. The is also a graph that shows what you will dink depending on bank/pich angle.

Practically speaking, most folks I have watched do use a mix of both techniques in strong crosswinds

[Samba Anaconda]

Yelena, your thread certainly brings out a number of closet B777 aces!

As for Old Smokey, woody and kickapoo......so refreshing to see such humility in this testostrone driven business.

[Chuck Canuck]

SpaceNeedle,

Well done, for shooting yourself in the foot

He may not have shot himself but he surely made life difficult for the poor sod involved. I do know that anal Canuck countryman of mine........he can be very vindictive and I guess he is sharpening that knife ready to strike!

[totempole]

Chuck, is he the one who did speedy gonzales in when speedy was made training chief on the 777s a few years ago?

[777pilotchina]

I seriously need some input here,
I used to fly the 738 for 5-6 years and now I'm doing my transition to the T7,
I would say i could do a 35kts Xwind landing on a 738 with my eyes closed and hands tied up!!!

In the T7, I'm now going koo koo!! WTF..... is like, I used to land the main wheels with the crab on the 73 and then apply ruder and aileron to fix the B***....or I would fly it down to the ground and level off with the horizon right before touch down and applying a bit more thrust during flair not to have the nose up attitude in order not get blown away... Always made perfect!!

Lower pitch...Higher power setting just did it.....


Now, in the T7, I can't have flare at lower pitch (3 - 4) and add more thrust to compensate for it cause we are not allowed to over-ride the A/T,
on the other hand, in the sim, I'm blown to one side of the centre line on each and every landing when i use the suggested 4-5 degrees pitch during the final phase of the flare!!

not to mention it seems like I need full freaking rudder to align my self with the centre line.. (35 kts Xwind, not gust)....


I really appreciate any input from the B777 experienced boys here!!! oh yeah, I've fully read the FCTM and all other manuals with regards to the suggested techniques..

[FullWings]

Hmmm. What do your sim instructors have to say about it?

I would be wary of attempting to use a non-SOP technique from another aircraft. From what you describe, it sounds like you’re flaring maybe a little too much if you’re picking up significant drift in the de-crab? The wing produces a lot of ground effect, counterbalanced a bit by crossed controls and slip angles.

As for the rudder, I have yet to run out of authority. The 777 is a fair bit bigger in all dimensions than the 737 (which is what I came from, too) and if you attempt to align your heading with that of the runway at the same angular rate, you’ll be trying to move metal much more quickly. Maybe slow down the manoeuvre a tad?

No two sims are alike, in my experience. When I converted onto type, one sim rattled your teeth and the other one was always like butter, no matter what you did with the aircraft. When you get onto the real thing, I bet you don’t have any problems.

[LeadSled]

Folks,
What are the autoland limits x-wind for the T7, and how does that do it?
For what it is worth, I always preferred slipping across the wind ( aka "wing down") on the 767, which is what the AP did below 500'.
With the B747/2/3/4 on a wet runway I preferred landing with the drift on, particularly in lousy viz, but would kick the drift off on a dry runway.
Whatever, in all cases you MUST maintain the attitude, let the nose drop as you kick the drift off and guess what --- big crunch ---- just like with no drift, and not controlling the pitch on any landing.
Tootle pip!!
PS: Would love to have flown the T7, if the sim. is anything to go by.

[PEI_3721]

Differences in mass-inertia response.
Aerodynamic control response, amount of rudder required as speed decreases. Roll-Yaw ratio, pitch rate and pitch damping; ground effect (higher in T7).
Simulators may not provide a realistic side force - lateral acceleration, thus essential body feedback is lacking. This can be a big issue for aircraft with lateral directional characteristics where fine control depends on good feedback.

Fly as per the book to provide a datum, then with experience evaluate each of the above factors to optimise technique.
Attempting to use a previous type as a datum can be confusing. All aircraft fly, and can be controlled in a similar manner, but similar is not always very close to 'the same as'.

[noblues]

I've been on 747-400's for years and have a 777 conversion in the near future.

So just to confirm ... there is no risk at all of hitting a pod on the 777?

(Unlike the 747 where its a VERY big issue in strong X-winds).

[wiggy]

Unlike the 747 where its a VERY big issue in strong X-winds

Ah ha, indeed, I do recall having issues, On an approach with a new P2 on the 744 who had come across from the 777 and for some reason claimed he had never been briefed/taught about pod strikes by our 744 trainers.

there is no risk at all of hitting a pod on the 777?


Our ultimate X-wind limit (dry) is 45 knots but the FCTM also states "Sideslip only (zero crab) landings are not recommended with crosswind components in excess of 28 knots...this recommendation ensures adequate ground clearance.......so it seems there can be a pod or tip problem if you sideslip.

[sleeve of wizard]

A pod scrape is possible on the 777, Boeing provides a graph in the FCTM. It depends on the pitch attitude.
Conditions
pitch about main gear centreline
Static strut compression
valid for all control surface positions
valid for all flap detents