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-   -   Crosswind Landings (https://www.pprune.org/tech-log/271547-crosswind-landings.html)

212man 17th April 2007 20:13

Air Rabbit,
I think when you are dealing with someone willing to describe themselves in these terms (in the Level D thread):

"I started my flying career since 1990 when i rapidly gained my licenses(7 months) but it wasnt till 2000 when I operated my first commercial flight on a glass cockpit heavy turbo prop.With almost ten years of absence from flying and a meagre 300 hours behind me(I am now a seasoned Pilot), I aced the real Simulator and so was my base(managed Base in only 3hrs) and line training was just as satisfactory"

Then you are on a losing battle with the point you are trying to make to AHRS!

AirRabbit 17th April 2007 22:08

212man: Point taken, thanks! My excuse? I have been accused of lobbying for the vacant position of "Patron Saint of the stubbornly ignorant and of the defiantly stubborn."

Slickster 17th April 2007 22:55

My advice on the sublect would be confined to Boeing jets, as it was too long ago for me to remember what it was like on Tobagos, Cessnas etc.

The "kick off the drift, and flare, all at once" technique is definitely the way to go. Trouble is, that it's not that easy; that's why you get paid the money! The "cross control" technique is easier, and tempting, but you are compromising your aircraft's flying characteristics by doing it (all those Vref calculations, based on weight, and now you are over the threshold with control surfaces working against each other).

Last point. If you ever end up flying a 747, remember that the landing is not over until you reach about 60 kts! That wing just keeps flying. Caught me out a few times.

dash6 18th April 2007 00:04

So at the point of impact (sorry,touchdown) Your airplane should be pointing down the runway,with no drift,and in an attitude that will result in rubber bits only contacting the ground;and a rate of descent that will allow you to use the airframe again without major maintenance. Got it.:) :)

AirRabbit 18th April 2007 12:45

I just love it when someone zeros in on the salient points of a discussion! Thanks dash6.

GearDown&Locked 18th April 2007 13:34

Err...sorry to interfere guys, but from what I've seen on 763 Jock's video, those planes all made contact with the rwy still facing the wind, after which they turn the nose into the rwy direction, extending the flare attitude time by the necessary secs to line the nose up.

I understand that this footage is related to Boeing test flights and therefore done in extreme conditions, but this represents the correct way to handle it, right?

GD&L

lefthanddownabit 18th April 2007 21:30

Those Boeing test flights are for certification at extreme crosswinds, with no passengers on board to complain. :eek:

I think it's instructive to see what the autopilot does, as "George" has no opinion, only programming.

On the 747-400 the autopilot uses crab angle, but at 500 feet AGL inserts up to 5 deg sideslip (i.e. wing down) to reduce it as much as possible without risking a pod strike. It lands wing down, with some crab depending on how strong the wind is. So with winds where crab angle would be less than 5 degrees, the autopilot technique at touchdown is exclusively "wing down".

757 and 767 autopilots use similar technique (crab then wing down).

The 747-200 in contrast will crab in until just 2 feet Radio Altitude at which point Kick Off Drift mode activates to start driving the rudder to line up with the runway. Clearly without a proper yaw channel they didn't want to take any chances. :)

AirRabbit 18th April 2007 21:47

Hey GearDown&Locked

Err...sorry to interfere guys, but from what I've seen on 763 Jock's video, those planes all made contact with the rwy still facing the wind, after which they turn the nose into the rwy direction, extending the flare attitude time by the necessary secs to line the nose up.
I understand that this footage is related to Boeing test flights and therefore done in extreme conditions, but this represents the correct way to handle it, right?
You are correct about these being test flights - but landing while still crabbed is done as part of the test - i.e., how badly will such a landing damage the landing gear and its components, etc. You'll note that in one sequence, the aircraft actually touched down on the down-wind gear first! That certainly isn't standard practice.

...and, by the way, I don't think you are "interfering" at all; as for me, your comments and questions are just as welcome as anyone's.


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