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Guest cw1011

Landing a 747-400 with autopilot and approach mode

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I'm trying to land a 747-400 using the autopilot and settingthe approach mode in the autopilot.What is happening seems to be that when the glidescope indicatetime to turn right to intercept the ILS the I lose height and thespeed goes up and I hear warning sounds. I come in to low and crash.What needs to be done?Before the turn what should my speed and flaps be. According to a book about Big Jets a 747-400 has a speed at 170 KIA when in traffic pattern.This does not seem to work.When must I disengage the autopilot and handfly the airplane?Also where is the VSI on the 747-400 panel?

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Are you adding power? If you are at 170 in the pattern, you should have a couple notches of flaps down and likely be thinking about gear. Lots of drag. Add to this the tendancy of airplanes to lose altitude in turns, especially tight ones to catch the localizer, so you not only have to pull pretty agressively on the yoke to keep the nose up, you have to add power so you don't lose speed. With jets, you end up coming across the threshold with a lot of power on, because jets are big, heavy and glide like bricks. This is also true of the little sportscars like the Lears and Gulfstreams.With full flaps, you get added lift, but a lot of drag. With the Wilco PIC 767, depending on weight, N1% will be somewhere between 55% and 60% on approach. Two other tricks to making your landings easier:1) Give yourself a long final. I usually try to plan my approaches in any jet with at least 15 miles of final. This gives you a lot of time to get stable and on the localizer.2) Capture the glideslope from below. If you look at an approach plate, you will see an entry point to capture the glideslope and localizer. Unless there are geographic constraints (i.e. a mountain etc.) You want to be flying straight and level when the GS becomes active (or be descending at a much lower rate than you will when you are tracking the GS), and most airlines will want their pilots to have slats out and likely one or two notches of flaps (about 170 knots in a big without a lot of gas on board) at this point. It's a lot easier to ease off on the power to increase rate of descent than to nose down to capture the GS and then add gear and flaps and use trim to bleed off speed to your final approach speed. Way back when, I read a good article on the whole concept of the stablized approach, which is essentially that you want your plane configured properly and stable between 15 and 20 miles out, before you start your final. I'd do a search for articles using "stablized approach" here and on the web. I'm sure you will find a ton of good stuff. I know that my landings usually suck if I turn into final too soon and too high. It's a lot easier to manage straight and level or a gentle climb, than a "dive" for the glideslope.Good luck. Have fun. It will take practice but you will really feel proud of yourself when you can get to the point when you don't need to hit the approach button and can do it yourself.

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JF:CW is right on with his recommendations on a stabilized approach. A few years ago, I had the chance to talk with a retired 737 captain about a similar problem I was having with my approaches, and he said the key was to stabilize the aircraft, in terms of airspeed and attitude, well ahead of time. I'm not an airline pilot, and it's been a while since I've looked at the V-speed charts for a 744, but I do think 170 KIAS is a bit slow to be maneuvering a 747-400 around in the pattern. At this airspeed, with the added drag of the deployed slats and flaps, you are already inching close to stall speed. And at pattern altitude, there would be little margin for recovery if you stalled a 250 ton airliner. Just my 2 cents. 190-200 KIAS with 2-5 degrees of flap seems to work well for me with 33% fuel remaining in the tanks. And I usually refer to the published ILS approach plate for the target altitude to intercept the glide slope usually somewhere around 3000 to 5000 ft, depending on terrain or location. Descend to this altitude as you turn onto base if you're flying the pattern, otherwise ATC will likely clear you down to altitude well ahead of time. Hope this helps.http://mostrealisticai.projectai.com/images/northwest.gifAlex ChristoffN562ZMinneapolis, MN

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>Are you adding power? >I initially fly on autopilot with auto throttle and it seemsthat the autopilot can't handle the situation. But shouldn't itbe able to do so?>If you are at 170 in the pattern, you should have a couple >notches of flaps down and likely be thinking about gear.I have 5 or 10 degrees of flaps and gear down >Lots of drag. Add to this the tendancy of airplanes to lose >altitude in turns, especially tight ones to catch the >localizer, so you not only have to pull pretty agressively >on the yoke to keep the nose up, you have to add power so >you don't lose speed. >I don't touch the yoke I leave it to the autopilot>1) Give yourself a long final. I usually try to plan my >approaches in any jet with at least 15 miles of final. This >gives you a lot of time to get stable and on the localizer. >I follow instruction from ATC and they don't give me 15 miles.>2) Capture the glideslope from below. If you look at anI do. >Good luck. Have fun. It will take practice but you will >really feel proud of yourself when you can get to the point >when you don't need to hit the approach button and can do it >yourself.As I said hitting the approach button doesn't help me it makesthe plane crash in front of the airstrip.Maybe I should point out that I wan't to create so realistic flightsas possible. and in real flight you listen and obey ATC and you useautopilot and approach mode (mostly).

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>looked at the V-speed charts for a 744, but I do think 170 >KIAS is a bit slow to be maneuvering a 747-400 around in the >pattern. At this airspeed, with the added drag of the >deployed slats and flaps, you are already inching close to >stall speed. And at pattern altitude, there would be littleBut I got this figure from a book about flying real jets(Flying the Big Jets by Stanley Stewart) >margin for recovery if you stalled a 250 ton airliner. Just >my 2 cents. 190-200 KIAS with 2-5 degrees of flap seems to >work well for me with 33% fuel remaining in the tanks. And I I tried those speeds to with the same result i.e my airplanecrashed before the airstrip.Regarding the fuel it was a flight from Munich to Milano startingwith full tanks.

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You're simply too heavy. There's no need to have full tanks for such a short trip. Try 25 percent fuel instead.

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Bingo. Pattern speeds would likely be for a plane with its divert plus one hour fuel on board and maybe a little extra cause you can't get it once you are up in the air. A 747-400 can carry enough fuel to fly for the better part of 15 hours. Your Munich to Milano flight probably didn't make much of a dent. I'm pretty sure they would have to dump fuel to land a plane that heavy.

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I've always had the same problem so that I even stopped using the autopilot in short final. Maybe you are right, perhaps I carry too much fuel. How much does a real 747, for example, carry when it's going to land? 5-10%?

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