PhilSquares From , joined Dec 1969, posts, RR: Reply 2, posted (7 years 3 months 3 weeks 1 day 2 hours ago) and read 9663 times:
There are two "acceptable" techniques for crosswind landing. You saw the first, landing in a crab. The second one is aileron/rudder cross control. Both are acceptable.
Personally, I use the aileron/rudder, to me, it's a smoother touchdown in that you're already aligned with the runway. Thus the person all the way in the back doesn't get the ride of their life.
Poitin From , joined Dec 1969, posts, RR: Reply 3, posted (7 years 3 months 3 weeks 1 day ago) and read 9601 times:
Quoting PhilSquares (Reply 2): There are two "acceptable" techniques for crosswind landing. You saw the first, landing in a crab. The second one is aileron/rudder cross control. Both are acceptable.
Personally, I use the aileron/rudder, to me, it's a smoother touchdown in that you're already aligned with the runway. Thus the person all the way in the back doesn't get the ride of their life.
Thank you -- one of the people in the back.
However, isn't the crab landing also toughter on the landing gear and particularly the tires? They have to be dragged sideways for some distance.
Bri2k1 From United States of America, joined Dec 2004, 988 posts, RR: 4 Reply 5, posted (7 years 3 months 3 weeks 10 hours ago) and read 9430 times:
Quoting Poitin (Reply 3): However, isn't the crab landing also toughter on the landing gear and particularly the tires?
Good pilots, and especially those who want to remain pilots, don't do things outside of the limitations of their aircraft. In a light training twin, you never put a side load on the gear or it will collapse right under you. In a 777, it's a very different story. As long as you know the limitations and adhere to them, it's not "tougher," any more than saying that climbing out at 2,500 FPM is tougher on the engines than climbing out at 1,500 FPM at the same airspeed. Sure, the engines might be working harder, but they're supposed to do that. The same thing applies to the landing gear.
PhilSquares From , joined Dec 1969, posts, RR: Reply 6, posted (7 years 3 months 3 weeks 10 hours ago) and read 9430 times:
Quoting Poitin (Reply 3): However, isn't the crab landing also toughter on the landing gear and particularly the tires? They have to be dragged sideways for some distance.
There is an increase in tire wear, however, the landing gear is stressed for that. The distance isn't that great because if you don't de-crab very quickly, you won't maintain the centerline.
Rendezvous From New Zealand, joined May 2001, 499 posts, RR: 0 Reply 8, posted (7 years 3 months 2 weeks 6 days 20 hours ago) and read 9288 times:
JAGflyer - if you dip the wing in the big jets you might hit an engine on the ground, that is in a strong enough crosswind. The aircraft are designed to be able to be crabbed, and cross-wind limits are imposed in the aircraft operating manual.
Sabenaboy - they sure abused that 777 during testing! It makes you respect what it can really do if it needs to.
Sabenaboy From Belgium, joined Feb 2001, 187 posts, RR: 1 Reply 9, posted (7 years 3 months 2 weeks 6 days 19 hours ago) and read 9258 times:
Quoting Rendezvous (Reply 8): if you dip the wing in the big jets you might hit an engine on the ground, that is in a strong enough crosswind
Rendezvous,
Even in big jets the opposed rudder and aileron technique can be applied, like PhilSquares already said in reply 2.
(That's also my preferred method in light crosswinds)
But you are right when saying that the pilot should be careful when dropping the upwind wing. Not more than a few degrees of bank is really no problem at touchdown in the A320: At a normal pitch up of +/- 5 degrees at touchdown, the aileron would hit the ground if bank exceeds +/- 14 degrees.
In strong crosswinds I'll combine both methods: take out part of the crab during flare with rudder/aileron and accept the touchdown with a little crab angle left.
AeroLargo From United States of America, joined Feb 2006, 1 posts, RR: 0 Reply 10, posted (7 years 3 months 2 weeks 4 days 20 hours ago) and read 9029 times:
Don81603 From Canada, joined Jul 2005, 1185 posts, RR: 0 Reply 11, posted (7 years 3 months 2 weeks 4 days 15 hours ago) and read 8966 times:
Quoting PhilSquares (Reply 2): Thus the person all the way in the back doesn't get the ride of their life.
Ah, but some of us nut bars like that wild ride!
On a similar note, a flight I was on (Airbus 319). almost immediately after takeoff, the aircraft banked hard to the right. It took me by surprise, but the pilot announced that "Thanks to an unexpected crosswind, we no longer have to turn towards calgary. Mother Nautre has done that for us." Does this sound reasonable, or was there something they weren't telling us?
Eagles may soar, but weasels don't get sucked into jet engines.
Grbld From Netherlands, joined Dec 2005, 353 posts, RR: 3 Reply 12, posted (7 years 3 months 2 weeks 4 days 1 hour ago) and read 8867 times:
Quoting Don81603 (Reply 11): Does this sound reasonable, or was there something they weren't telling us?
Mother nature (ie. wind) can't actually change the course of an aircraft much so it was most likely a wake turbulence vortex from a preceding aircraft they flew through. Those are the ones that'll give you a sudding wing drop like that.
When banking an aircraft, it doesn't even necessarily turn very well. Try it with the yaw damper turned off, it normally applies automatic rudder to coordinate the turn — with it off, the plane hardly turns.
Miller22 From United States of America, joined Nov 2000, 707 posts, RR: 5 Reply 13, posted (7 years 3 months 2 weeks 3 days 18 hours ago) and read 8789 times:
The wing-low method is always preferred, unless you stand the chance of hitting an engine. That's why you'll always see 747's and B52's crab it all the way it.
When you land crabbed, the wheels actually skip across the ground, and its actually bumpier. The trick is to straighten the nose at the last second to get the wheels pointed in the right direction without giving the crosswind enough time to push the aircraft sideways.
PhilSquares From , joined Dec 1969, posts, RR: Reply 14, posted (7 years 3 months 2 weeks 3 days 6 hours ago) and read 8717 times:
Quoting Miller22 (Reply 13): The wing-low method is always preferred, unless you stand the chance of hitting an engine. That's why you'll always see 747's and B52's crab it all the way it.
Really? The B-52 has crosswind crab settings you can dial into the MLG. The 747/744 it's different. I can't think of a single carrier that advocates landing in a crab. Most use aileron and rudder to align the body with the runway.
Miller22 From United States of America, joined Nov 2000, 707 posts, RR: 5 Reply 15, posted (7 years 3 months 2 weeks 3 days 2 hours ago) and read 8668 times:
Quoting PhilSquares (Reply 14): Really? The B-52 has crosswind crab settings you can dial into the MLG. The 747/744 it's different. I can't think of a single carrier that advocates landing in a crab. Most use aileron and rudder to align the body with the runway.
The B52 lands in a crab. They've got the wheels to do it. The 747 crabs all the way in, and kicks the rudder at the last second. I don't know the bank angle of the 747 before it hits the #1 or #4 engine, but it isn't much. Anything over a 10-15 knot crosswind, and it's hitting an engine unless you crab it to the flare. Read the part of my post you failed to quote, about straightening the nose at the last minute to prevent side loads on the gear and drift.
PhilSquares From , joined Dec 1969, posts, RR: Reply 17, posted (7 years 3 months 2 weeks 3 days 2 hours ago) and read 8662 times:
Quoting Miller22 (Reply 15): The B52 lands in a crab. They've got the wheels to do it. The 747 crabs all the way in, and kicks the rudder at the last second. I don't know the bank angle of the 747 before it hits the #1 or #4 engine, but it isn't much. Anything over a 10-15 knot crosswind, and it's hitting an engine unless you crab it to the flare. Read the part of my post you failed to quote, about straightening the nose at the last minute to prevent side loads on the gear and drift.
When you have 1000 hours in a 747 you can tell me how to land. It's not quite like you describe. You are incorrect in saying that's all there is to the landing.
The B-52 maintains it's crab through the touchdown, because the wheels are actually going straight down the centerline. The 747/744 takes a little more than, as you say "kidking the rudder at the last second"! As far as 10-15 knots crosswing hitting a pod, you're wrong. With a 45 know x-wind you can use rudder and opposite aileron to keep the body straight and the wings will still be level!
My FCOM says 7 degree for a pos scrape, so I won't argue with 6.5. However anything over 1-2 is well beyond what you need.
Miller22 From United States of America, joined Nov 2000, 707 posts, RR: 5 Reply 18, posted (7 years 3 months 2 weeks 3 days 1 hour ago) and read 8634 times:
Quoting PhilSquares (Reply 17): When you have 1000 hours in a 747 you can tell me how to land. It's not quite like you describe. You are incorrect in saying that's all there is to the landing.
I guess I don't get it. You take a paragraph to tell me I'm wrong, and then you say the exact same thing I did. Nor did I say "that's all there is to the landing." Its like saying pushing forward on the thrust levers and pulling back on the controls is all there is to flying. Perhaps you're just interested in arguing something to show what you "know" (or think you know).
Quoting PhilSquares (Reply 17): The B-52 maintains it's crab through the touchdown, because the wheels are actually going straight down the centerline.
Please reread my posts. You'll find I said the same thing
Quoting PhilSquares (Reply 17): The 747/744 takes a little more than, as you say "kidking the rudder at the last second"! As far as 10-15 knots crosswing hitting a pod, you're wrong. With a 45 know x-wind you can use rudder and opposite aileron to keep the body straight and the wings will still be level!
Aerodynamically, you are incredibly mistaken if you think you can straighten the nose of any aircraft with rudder in a crosswind, not compensate for it with any aileron, and maintain straight flight in relation to the runway. And in a 45 knot crosswind!?!? I've never heard any pilot make that claim, most likely because the laws of physics prevent it. Any aircraft will drift in those conditions, regardless of size. The only way to combat drift is to crab, or dip a wing. You dip a wing in the 747 and...scraaaaaaaape!
L-188 From United States of America, joined Jul 1999, 29352 posts, RR: 62 Reply 21, posted (7 years 3 months 2 weeks 2 days 23 hours ago) and read 8588 times:
Quoting PhilSquares (Reply 14): The B-52 has crosswind crab settings you can dial into the MLG.
The C5A had a similar system for it's MLG. But is is widely accepted as the source of all those C5A on jackstand jokes, so the airforce got rid of it on the B models.
OBAMA-WORST PRESIDENT EVER....Even SKOORB would be better.
Zeke From Hong Kong, joined Dec 2006, 7729 posts, RR: 73 Reply 22, posted (7 years 3 months 2 weeks 2 days 23 hours ago) and read 8579 times:
Quoting PhilSquares (Reply 17): My FCOM says 7 degree for a pos scrape, so I won't argue with 6.5. However anything over 1-2 is well beyond what you need.
7 degrees corresponds to a body pitch angle of 3 degrees for PW&GEs, or half a degree for RR.
I had assumed a prolonged flare which will increase the body pitch angle by 2 to 3 degrees.
We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
Jetlagged From United Kingdom, joined Jan 2005, 2452 posts, RR: 17 Reply 23, posted (7 years 3 months 2 weeks 2 days 23 hours ago) and read 8576 times:
Quoting PhilSquares (Reply 17): With a 45 know x-wind you can use rudder and opposite aileron to keep the body straight and the wings will still be level!
Sorry, but no, the wings will not be level. Your crosswind landing technique is not called "wing low" for nothing. A 45 knot crosswind at, say, 155 knots airspeed will give you a sideslip angle of around 17 degrees. Using rudder and opposite aileron to compensate for that will give you significant bank angle.
I'm looking at Boeing flight test data for the 747-400D for a landing case (flaps 30, 286 tonnes), sideslip of 13.7 degrees, at an airspeed of 160 knots. That corresponds to a crosswind about 38 knots. The roll angle is 10 degrees.
Full rudder (30 degrees) is applied, which means that is the maximum crosswind the aircraft can compensate for at that airspeed using cross-control. So 45 knots would not be possible using sideslip alone.
Cross-control data is usually fairly linear, so interpolating for a 30 knot crosswind, the bank angle would be around 7.9 degrees. That's pushing the limit of 7 degrees.
Now in an engine out situation, if you use rudder to zero sideslip, then you will have wings level.
The glass isn't half empty, or half full, it's twice as big as it needs to be.
Zeke From Hong Kong, joined Dec 2006, 7729 posts, RR: 73 Reply 24, posted (7 years 3 months 2 weeks 2 days 22 hours ago) and read 8550 times:
Quoting Jetlagged (Reply 23): Sorry, but no, the wings will not be level. Your crosswind landing technique is not called "wing low" for nothing.
Know three techniques for the 744 ...
De-crab during flare
Crab
Sideslip (wing low)
Been a while since I have done an autoland in a 744, from memory the autopilot uses a combination of de-crab during flare and crab. Crab alone is not recommended above 20 kts.
With the de-crab during flare it is possible to maintain wings level, as rudder is applied during the flare, aileron is used to maintain wings level.
With the sideslip (wing low) technique it would be necessary in strong winds to land with some crab as well as sideslip. Highest risk of pod strike, or runway contact with the outboard flaps.
Reading Phils post 17, he seems to use the de-crab during flare technique, not the sideslip (wing low) technique your talking about.
I have never liked the sideslip technique on any jet, I use the de-crab during flare technique, and will use the smallest amount of roll if drifting in the flare.
From memory, for contaminated runways or OEI, reduce the max crosswind by 5 kts on the 744.
We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
25 Pihero: Sorry to barge in so late, but I'm puzzled by Jetlagged's figures : I used to fly -and love - the Tristar as a captain. The recommended crosswind land
26 Miller22: Its simple physics really. With an aircraft landing in a crosswind, longitudinal axis straight with the centerline, and no dipped wing, ANY aircraft w
27 Jetlagged: No, I'm not confused, nor has Boeing's document got a typo. Of course the angle of sideslip equals the drift angle. That's how you can keep on the ce
28 Wing: I really had difficulty to understand some of the posts in this thread saying a lot of "useful" information about angles,degrees and knots etc. We don
29 Pihero: Sorry, I got confused with angle of sideslip (which we can't know) and the bank angle. As I said earlier, my experience on the Tristar gave a slip of
31 PhilSquares: Miller22, I'm not going to debate you at all. Obviously, you're much more experienced than I could ever hope to be. My point is you make it sound as
32 Jetlagged: I don't have a link to it, and it's Boeing proprietary data so I couldn't post one if I had. The data is a snapshot of a full rudder cross-control co
33 Zeke: Unlike a 150, the 744 has a couple of hundred tonnes of mass, think some physics buff called newton came up with some words called his first law to d
34 Bri2k1: I don't understand why the "flight simulation consultant" is telling the 744 captain how to land. PhilSquares, welcome to my RU list.
35 Zarniwoop: I'm trying to understand the two different techniques, so I have drawn a little diagram. BTW, the blue arrows indicate the deflection of the control s
36 Zarniwoop: Sorry if this video has been posted before, but there is some great footage of 777 & 747 cross wind landings http://www.kayakcam.com/image/boeing-777-
37 Bri2k1: Zarniwoop, The only thing wrong with the diagram is the blue arrows in the sideslip diagram. The idea behind sideslipping is to direct some of the ver
38 Sabenaboy: Miller22 is correct when stating this. In A STEADY STATE it will apply. If You keep the wings level and the nose pointed to the runway end, the cross
39 David L: And I apologise to all parties for sticking my nose in. Didn't exactly add value to the discussion.
40 Miller22: You know, the dynamics of this thread are quite interesting. I guess pilot ego's are as large world-wide as they are in the US. First, Phil jumped all
41 Jetlagged: I must have missed something. In none of my posts did I tell any 744 captain how to land. I questioned his comment about 45 knot x-wind, which he imp
42 Jetlagged: No, that's sideslip. Forward slip is an FAA term used to define a way to lose altitude without gaining speed, using the sideslip as drag, in other wo
43 Bri2k1: Yes, that is my profession, I am only a pilot for fun. That doesn't mean I don't know what I'm talking about, though; as you will notice in my posts,
44 PhilSquares: I guess I don't understand your point! I was not berating anyone, just trying to put things in perspective. One of the things I have learned as a Cap
45 Neilking: Phil - very interesting point you make there. I am not a pilot - it doesn't matter what I do - but suffice to say I'm the leader of a small team (4 p
46 David L: No need to check your profile to see where you're from! Well done for not going into a full-blown "Jings, crivvens, help m'boab". I've got a few 744
47 Pihero: Re- sorry to barge in again, as no one seems to have taken my point seriously (which I resent ). This is a video of an MD-11 landing, using the 2wing
48 Zeke: Phil, Might need to also explain how long it takes from making a smooth control input to getting the desired result, and how exacly the control input
49 PhilSquares: First of all, in a swept wing aircraft, the rudder is more effective at higher angles of attack than the ailerons. So, just a little rudder goes a lon
50 David L: Just to clarify, I was adding to Sabenaboy's post, not replying to it, and I meant me sticking my nose in didn't add to the value of the discussion.
51 David L: For what it's worth, I took it seriously . The video does seem to me to back you up but I'm probably not the best judge!
52 Meister808: That is exactly what we see in this video. When it starts, you can see the runway is pretty evident in the right pane of the windshield, meaning the
53 Jetlagged: I'm not asking for your respect. You accused me of telling a 744 captain how to land, which I repeat, I didn't do. I only disagreed with him about so
54 Bri2k1: Well, Jetlagged, that's the beauty of the RU feature...I can do with it what I please Neither your instructions nor anyone else's will influence my us
55 Redcordes: If the wings are level and the aircraft is aligned with the rway, where is the aerodynamic force coming from that is causing the aircraft to fly enou
56 Jetlagged: I'm not instructing you on how to use the RU feature. I'm certainly not asking you to change how you use it. However, I don't appreciate how you inte
57 Bri2k1: Why do you think I'm not a pilot? As I stated before, I am a pilot, I just don't accept money for it.
58 PhilSquares: Again, at higher angles of attack, on swept wing airplanes, the rudder is EXTREMELY effective. During the flare, the rudder is much more effective th
59 Redcordes: OK PhilSquares. Either the rudder is pointing the aircraft into the wind (crabbed) or it is aligning the aircraft with the rway. If the aircraft is al
60 PhilSquares: Redcordes, I'll try this again. Pleae re-read what you posted and tell me where I said it was rudder only? Where did I say it was, as you imply, coord
61 Sabenaboy: PhilSquares, I think that you'd better stick to that explanation. I'm sure that you know how to make a perfect crosswind landing in a 747. I think yo
62 PhilSquares: Sabenaboy, believe it or not, I have a degree in Aero, so while I'm not quite as experienced as you, I do know the physics behind the transition to l
63 Sabenaboy: Philsquares, You're right. It's time to leave this discussion here. I regret I can't be with you in SEL to have a beer and talk about what's really im
64 Zeke: Trying to put some mathematics behind a cross wind landing situation that Phil was talking about. Just like to compare a C150 and a 744 in a 45 knot c
65 Jetlagged: Maybe I missed a comma somewhere, I meant me as the non-pilot, apparently not deserving courtesy from you, the pilot. If you want people to know you
66 Vikkyvik: Sorry to bring this thread back to the top. However, I was wondering if any/all of you could decipher what exactly is (probably) occurring at this poi
67 Starlionblue: There are 10 kinds of people, those who understand binary and those who don't. You seem to misunderstand the purpose behind these forums.
68 MDorBust: Given the crazy super gusts we've been haveing for the past couple of months here in the DFW area, I would suspect he was the victim of a very strong
69 Vikkyvik: Heh, agreed. Agreed again . I thought we were here to argue. Reference the "Hypothetical Question" thread (too lazy to pull up the link). That very w
70 Pihero: The windsock indicates a crosswind of less than 10 kts. In this case there was a hell of a windshear...
71 777WT: That's alot of wing flex there on final.
72 MDorBust: Like I said, gusts. Not constant winds. A wind sock has a lot less mass than a 777 and will revert to a rest state alot faster than a 777 will. If th
73 Miller22: Just saw an excellent internet video of heavies landing in a crosswind. Lets see you try to straighten the nose at 200 feet and not hit an engine in t
74 Skyslave: Slightly off topic, but I have a question for all you airline pilots out there. When I'm flying a twin-engine and I'm landing in a strong crosswind (1
75 Sudden: I hope you are aware of that this is Boeing performing test-flights. The wind conditions might even be beyond the envelope/SOP. So I would not use th
76 Arrow: Must admit, when I was landing my Luscombe (slightly smaller than a 747, and fewer engines) in a stiff cross wind I would crab down to the threshold
77 777WT: These flights are for testing the main landing gear in extreme crosswinds, mainly for BFGoodrich.
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