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RandallR

A few questions about bad landings and perception

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Hey all,I'm a simmer and generally do very well. But every now and then I botch a landing by landing at an angle to direction of flight, hit hard, screech and swerve etc etc. I figured the sim was very forgiving and I just planned to do better next time. I figured if it was real life I'd be out of a job.Anyway, I was visiting www.airliners.net (now the source of all my desktops!) and I discovered quite a few photos of bad landings (not crashes). So some questions I have are in real life about commerical flying:How common are less than perfect landings? Are bad landings really that evident to the pax? Or does a bad looking landing not really feel like much?What are the consequences of a bad landing for the pilot? (I feel for the pilots, an error can mean the end of a career. Of course, there's the other side of that too....)I suppose I'm using the definition of "bad landing" as anything less than perfect.I know one time I experienced quite a bounce on landing and I *guess* that the plane probably bounced up like 10-20 feet. I couldn't see out the window at the time. I suppose if I could see it in replay I'd be quite disappointed.Please excuse me if I'm asking an awkward topic. I don't mean to upset anyone. I'm just curious about what it looks like from outside verus what it feels like inside, and what safety concerns there might be.ThanksTim Dobrowolsky

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Hi Tim,All we real world pilots have our share of bad landings, even high time pilots. The key is the expression" "Any landing that you can walk away from is a good landing".I fly small Cessnas, so my bad landings are usually too much flare in gusty cross winds invoking excessive side loads on the undercarriage. This you can definitely feel as being pushed to one side of the plane (which you won't be aware of in the sim, of course :) ).Larger aircraft, notably jets, are much less graceful on landing due to their swept wings. Also, large aircraft are better making a hard landing in the "touch-down zone" (a part of the runway designed for touchdown and marked accordingly) than a nice smooth landing outside of this zone.But- if your landing either damages the aircraft or causes you to lose control, then that's bad.Bruce.

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I've heard more than once that sometimes the hard, "thumper" landings in air carrier aircraft are intentional and done for safety reasons. A feather-soft, "greaser" landing is fine on a calm, dry day. The problem with soft landings is that for a few seconds you're subject to air physics and ground physics at the same time. With a strong crosswind and/or contaminated runway that can lead to a skid. For that reason, when conditions are less than optimum, the landing is intentionally firm so the lift from the wings can be quickly dumped to get weight on the tires, where it should be during ground roll.I should mention that I'm just a small airplane driver. Hopefully one of the resident air carrier pilots can either confirm this or tell me I'm full of it.Dan

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Interesting subject! I'm not a pilot myself (outside of FS) but have heard the "fly into the runway" instruction for rougher weather before. Like Dan said, the reasoning behind this is you wouldn't want to be caught in a crosswind with your pants, eh, engine power and vertical speed down or you'll float off the runway.Credits to FS realism today - this effect is IMO very well modeled (again, I can't compare to real pilot experience but it sure does feel right).Have had my share of *unintentional* rough landings as a passenger as well - but besides one forced overweight landing in a 737 never something that had me question the safety of the plane even for a moment. The vast majority of real-life landings made me hope I could even approach that level of smoothness in FS :-)Cheers!Vince

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If I may add a question to that to real-life pilots among you:When 'crabbing' towards the runway in a crosswind, there will have to be a moment to align with it. When is the best moment? Too soon will expose you to the crosswind too much, while too late will cost you your tires I guess.Anyone?Thanks!Vince

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Hi Vince,As well as crabbing, there's an alternate method of addressing cross-wind drift called a slip. Some pilots use this all the way down the final approach, and has the advantage that the plane's heading never deviates from the runway heading. The down-sides are it's harder to do (your rudder goes one way while your aelerons are trying to turn the other, going against all intuition), and it's uncoordinated flight, so the pax note some sideways forces (tend to push them, if extreme enough, towards the side of the a/c).Most pilots of small airplanes use one or the other- crab or slip. Slip as above all the way. And crab all the way which means your sense of timing needs to be good !! And many use a combo (getting back to your question)- crab down to 50' above the runway, rudder to scew the plane's nose back to runway heading (at this point the mass of the plane has been travelling along the runway heading, so it takes some time for the wind to move that mass from a zero cross wind speed), then a slip as required to maintain runway track (in that case you will toucn down on the upwind wheel first).When touching down, avoid too much flare in crosswinds, Flare is great to kiss the ground smoothly with a high nose up attitude and minimum ground speed, but in crosswinds you want to get those mains down hard and early.All this said- some airliners don't like slipping. The 747-400 has an issue with the outboard engine being so low that a slip can cause a ground strike. So they do have to time the exit of the crab very carefully. But with so much mass, it would take a relatively long time and/or big crosswind to build up any sideways interia.Good question.Bruce.

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Hi Vince,Wind speed tends to decrease as you get closer to the ground, so there isn't much advantage to slipping from a high altitude unless you are too high and want to lose some excess altitude. However you do a crosswind landing, the key is maintaining directional control from flare, to touch down and throughout the rollout. Landing in a crab may be hard on tires and your ego, but loss of directional control is the more serious side effect and can really ruin your day.In an aircraft with low wing loading (C172), staying in a prolonged slip on final can be uncomfortable for non-pilot passengers. In lighter planes, I prefer entering a slip just after crossing the threshold. This allows enough time to determine if there will be enough rudder authority to handle the crosswind. If you put in all the rudder and the nose still won't align with the runway just before you enter the flare, it's time to go around and try again with fewer or no flaps or find a different runway. In a heavier single or a twin, I prefer to exit the crab right before the plane touches down. As the plane starts to sink that last few feet toward the runway, ease in enough rudder to get the nose straight and lower the upwind wing slightly to maintain the centerline. Some people say "kick out the crab," but I like control inputs to be smooth and "kick" doesn't sound smooth to me.Even in a strong, direct crosswind, I'm not a big fan of getting the mains down "hard." The flare may be more abrupt in a crosswind landing, but it is still possible and desirable to strive for a smooth landing. You might be rolling on the upwind wheel for a few seconds before the other main touches down, so directional control is paramount.Landing a taildragger in a crosswind usually calls for a wheel landing (as opposed to a three point landing). You can't put the mains down hard in a wheel landing or you'll bounce and bounce and bounce ...In strong, gusting winds, maintaining directional control while taxiing to the runway in a light, high-wing aircraft or a taildragger can be just as challenging as the takeoff or the landing! ;-)I seem to remember reading that the C5 has a cockpit control that adjusts the alignment of the main landing gear to allow the plane to land in a crab. Maybe someone out there has more information?John

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Hi John,Glad to see you're still around - it's been awhile. :-)In my flying days I always crabbed in - can't really tell you when I took her out of the crab - maybe 10 ft. or so?...mainly, just when it felt right. Got pretty good at it, actually.My question to you is, are pilots still taught to deflect full aileron to the windward side when making a crosswind takeoff? That's the way I always did it - when I reached rotation speed and a little extra, I gave her a gentle "yank" and popped her off - as she became airborne she began turning into the wind, then I simply leveled the wings and settled into the climbout crab.Is a different technique used today?

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Hey Randall!Nice to see you're still here, too. I still make it to the forums from time to time. ;-)The technique you describe for x-wind takeoffs is pretty much what I teach in a 172. Ailerons fully deflected into the wind, then gradually reducing the deflection as you accelerate. Rotating briskly at a slightly higher speed than normal is also advised in a x-wind situation so you reduce the chance of settling back onto the runway in a crab. Once airborne, just level the wings, establish a positive rate of climb, and add right rudder. The plane will weathervane into the wind on it's own and pretty much establish the desired crab angle.See ya!John

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John,Just got back from vacation and I'm catching up on my messages.The gradual reduction method sounds interesting, as we held in deflection right into rotation.BTW, I don't know if you've had time to play around with the v240 Fly!II Patch, but many of the improvements that Rich was able to incorporate before his death (DME ident, etc.) came from you! Thanks for all the input! If Rich had lived longer, he probably would have incorporated all of your suggestions - as it was, he still pulled off some great corrections and improvements.

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