i know this has nothing to do with 767pic but ill ask anyway. i hear the terms crab, and slip, and skiding. what do they mean? does this skid mean the same as the skid refered to cars? i hear the term crab and slip when i read about landings. so could someone explain what these terms mean?Adam

These refer to Crosswind operations. Best Wishes,Randy J. [email protected]" A little learning is a dangerous thing"AMD XP 2100 |MUNCHKIN 512 DDR RAM |ECS[/b ] K7S5A MB |[b]GF3 64 MEG |WIN XP PRO |MITSUBISHI DIAMOND PLUS 91 19"

Ok,These terms refer to the different crosswind landing techniques.Skidding I have never heard of, but the other two are:1. CRABThe more commonly used method with large airliners, although the 767 and 757 can also use the SLIP or FORWARD SLIP (same thing) method.In CRAB you just point the a/c nose into the wind, so that the a/c will fly a straight TRACK towards the runway, with the nose NOT pointing into the runway, but into the wind. Once you are close to the runway, for example over the threshold ~ 40-50 ft AGL, you start to "kick" the a/c straight onto the runway with the rudder, i.e. you use the opposite rudder (with respect to nose position of course) to yaw the a/c nose straight back into the runway, so that the touchdown will occur JUST after the a/c has lined up on the runway centerline. If you "kick the crab out" too early, the a/c could drift to the downwind side of the runway, or in the worst case scenario OUT of the runway before touchdown. On the other hand, if you kick the crab out too late, the a/c could have contact into the ground in a crabbed attitude, which is REALLLLY bad for the landing gear. As an interesting sidenote, SOME large airliners are allowed to actually TOUCHDOWN in the crabbed attitude. The momentum of the movement along the runway centerline will straighten the a/c up after touchdown, PLUS the landing gear won't mind. One well known a/c of this type is the B747-200/400. With B757/767 it is not recommended to touchdown in the crabbed attitude.2. The SLIP or FORWARD SLIPThis method allows the pilot to actually point the a/c nose into the RUNWAY all the time during approach without drifting in the centerline at all. How is this possible ?Well, this is how it's done. You establish the a/c on the centerline (eg. localizer), and immediately start a BANK into the wind. Immediately AFTER the bank (some CFIs also instruct to do this at the same time with bank) you apply OPPOSITE rudder to counteract the a/c tendency to start a turn into the wind. So now you have crossed controls with a wing lowered into the wind and opposite rudder applied to keep the a/c from actually turning into the wind. In this SLIP configuration the a/c will fly towards the runway, with the nose INTO the runway and the upwind side wing slightly lowered into the wind.This attitude is kept (and finetuned) all the way to the touchdown, so the actual touchdown occurs to only ONE side of the main landing gear, and eventually the other side will drop too. Once both mains are down, you straigthen the controls to avoid the a/c going out of the runway.Also, as a sidenote again. In the CRAB method, sometimes it is useful to add a little "crossed controls" in the kicking of the crab out. What this means is that when you start to kick the crab out with the opposite rudder, you will also apply a little bit of the opposite (ie. the upwind) AILERON, to establish a SLIP attitude just before touchdown. This prevents the a/c from drifting away from the runway centerline in case you have started the un-crabbing too early.Hope this helps!regardsTero

If you look at your slip indicator below the adi you will see the ball inside. Say you are turning left....If the rate of turn is too slow for the angle of bank, lack of centrifugal force moves the ball to the inside of the turn. this is a slip.......If the rate is too fast for the bank the excessive force moves the ball outside the turn. this is a skid. In a slip you decrease bank or step on the ball(move the rudder toward the ball) or a combo of both....In a skid you increase bank or step on the ball or both...In the dc-10 we use the foward slip method...True some planes touch down in the crab..Larger planes like the B-52 and others use a system called crosswind landing gear system...This system allows you to adust the gear to align them with the runway while crabbed..Once on the runway you push the center button and the plane will realign on roll out...Even during the takeoff you can crab the plane and after liftoff you can retract the gear and they will center then retract. But this system is logistic nightmare....rich

Hi Rich!A quick question:Will an excessive slip at high altitude cause engine failure due to air starvation? (Besides all the remaining unconvenient side effects of a slip...)Thanks,Mark