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smokeyupahead

help with traffic patterns....

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Hi everyone, I was flying around today and did some searches with no results yet, what are the times in minutes required for a 747 to fly a traffic pattern?How long before I have to turn on the downwind leg and on all other legs, I know there's a clock in ready for pushback that allows you to keep trak of minutes of a go around or circuit.Thanks,David

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It can't be precisely answered because one pattern maybe different than another one - depending how long a final you want to fly. No pilot would "time-measure" such a thing.Michael J.WinXP-Home SP2,AMD64 3500+,Abit AV8,Radeon X800Pro,36GB Raptor,1GB PC3200,Audigy 2

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There is a chart at the bottom of the the Jeppeson aproach plates that gives leg times for the stages between the turning points on an approach, but it hasn't got all the available approach speeds, so you'll probably have to adjust the times for your approach speed. Why don't you save yourself a lot of hassle, and do a GPs approach? :-) BestGrahame (EDHL)

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David-- The simple answer is that B747s don't fly traffic patterns except in the extremely rare instance of a VFR landing at an uncontrolled airport on a non-commercial flight. All airline operations are flown IFR and at most air carrier fields approach control vectors the incoming aircraft onto final. Many times this may resemble a VFR traffic pattern with a downwind, a base leg and a final leg, but the turns are done at the direction of ATC. The lengths of the various legs are pretty much determined by how many planes are trying to land and the requirement for ATC to keep them separated.

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Dunno about a 747, but I did see a B-2 doing touch-and-goes at Tulsa one day!! :7 Seems like he was getting around the pattern about once every 10 minutes. Of course he was throwing that puppy into a hard right climbing turn at 50' off the tarmac ... very cool!!:-cool

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Donny AKA ShalomarFly 2 ROCKS!!!A technique that works for me if you really want to fly the full pattern is to mantain runway heading till 1000 feet then make a 90 degree turn level at 2000 AGL and go about five miles on the DME or GPS then make another 90 degree turn. The distance to airport will decrease till you are abeam it again. When the glideslope reads low or you are 15-20 miles out (for 747 a long final is nice) make another 90 degree turn to intercept the localiser.Best regards, Donny :-wave

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Although Bob is absolutely correct that 747 rarely would fly a typical circuit-pattern though if you take for example such airport as TNCM in the Carribean with good weather practicaly year-round and with sparse traffic it would probably not be unusual for a pilot to execute a perfect VFR approach even in a 747. If equipped with glass cockpit pilot would orient itself with respect to the symbol of the runway on the NAV display, then perhaps flew base (not necessary 90 deg to the runway), then final leg. With runway in sight he would be then flying like any other VFR pilot. All this of course in coordination with the TNCM tower.Michael J.WinXP-Home SP2,AMD64 3500+,Abit AV8,Radeon X800Pro,36GB Raptor,1GB PC3200,Audigy 2

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>>to intercept the localiser.>Not every runway has localizer :-waveMichael J.WinXP-Home SP2,AMD64 3500+,Abit AV8,Radeon X800Pro,36GB Raptor,1GB PC3200,Audigy 2

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Hey David,The closest thing I can think of is the airforce C5, KC110 and KC10 aircraft that I often see flying the touch-and-go pattern at Travis AFB (KSUU), north of Oakland. My guess is that these aircraft are flying a pattern with crosswind and base legs of 6 to 8 NM and a downwind leg of 10 to 14 miles.This just an estimate, based on seeing them pass over the traffic pattern at Rio Vista (O88). They usually announce over the Rio Vista CTAF that they are passing overhead at 2500', as they turn downwind to base for SUU RWY 21. My students are usually amazed the first time they see one of those big, gray beasts passing 1500' above them as they fly the Rio Vista traffic pattern.John

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Michael-- While it would be easy to fly a typical circuit at an airport with good VMC, an air carrier is still flying under positive control from ATC. It is not up to the pilot to fly whatever pattern he would like to fly, he has to fly where ATC tells him to fly. There are, of couse, visual approaches to many airports that are used in good weather, but these are still IFR approachs and the pilot either has to follow a charted path to the runway or is vectored to a final and then when he as the airport or a preceeding airplane in site to continue to land without reference to any electronic aids. I know a couple of pilots who have flown 747s for JAL. A typical part of the training for new pilots (which is done in the U.S) is flying touch-and-goes at an airport in California. They fly typical VFR patterns there but I don't know how far out they turn to final. I would guess that in order to be stablized at 1000' AGL, it would probably have to be about 5 miles.

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David,This is a visual circuit for a 767, but it should be similar for a 747 at similar weights.http://www.smartcockpit.com/b767/visual%20approach767.PDFBasically you are limited by the turning radius which is determined by the airspeed. Your minimum airspeed is based on the aircraft's weight, which will in turn affect the stall speed.The takeoff/climb and crosswind-to-downwind speed will typically be greater than the final approach speed, so the inital crosswind leg will therefore be wider than it might be had you were flying at final approach speed all the way around.Flying at final approach speed also requires greater flap settings that takeoff and climb. Conversely takeoff and climb typically does not permit "final apporach" flap settings, due to the excessive drag, which therefore requires higher airspeed.Final approach speed is usually 1.3 times stall speed + a margin for the wind... usually 5kts extra airspeed at a minimum even in calm conditions.E.g. at ~190 knots your turn radius is ~1 nm and slightly less at 140-150 kts. So the minimum crosswind length is ~ 2mi. If your pattern is 1,000 - 1,1500 agl, that also translates to a ~2-3 mi final approach.This is the "aerodynamics" answer, as others have mentioned, due to ATC, noise abatement, and IFR rules etc, in the real world, typically a 7nm final is the shortest that you'd fly. MikeHere's a neat little freeware turn radius calculator :http://www.gylesaero.com/download_counter/...sCalculator.zip

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>>While it would be easy to fly a typical circuit at an>airport with good VMC, an air carrier is still flying under>positive control from ATC. It is not up to the pilot to fly>whatever pattern he would like to fly, he has to fly where ATC>tells him to fly.I never said anything to the contrary. In excellent weather with visibility exceeding 10 miles pilots are often directed by ATC to fly visual approaches. Yes, many of them are published visual approaches.Michael J.WinXP-Home SP2,AMD64 3500+,Abit AV8,Radeon X800Pro,36GB Raptor,1GB PC3200,Audigy 2

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Thanks guys, the reason why I posted such a question is that I see a lot of commercial aircraft flying these patterns at my local airport LIBP, and I know that only some of them could be student pilots.On the other hand maybe smaller airports like the one I live close to allow these procedures since there is doesn't comprimise safety and is very little influent for congestion purposes; at a big international hub things might be a little different.Now what does the "12 minute event timer" function on the onboard clock do for an ailiner like the 747-200?Is it to be used in the event of a missed approach, and how?Thanks to you all, aviation is amazing!David

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I fly out of Buchanan Field (KCCR) in Concord and sometimes pop over to Rio Vista for pattern work when Concord's busy. The C5's do look awfully big and slow when you're flying towards them at roughly the same altitude, but then they seem to get a lot faster as you get closer.Richard

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>Thanks guys, the reason why I posted such a question is that>I see a lot of commercial aircraft flying these patterns at my>local airport LIBP, and I know that only some of them could be>student pilots.I don't know what you mean by student pilots. All aircraft, whether flown by a student pilot or an ATPL have to follow the same rules :)>On the other hand maybe smaller airports like the one I live>close to allow these procedures since there is doesn't>comprimise safety and is very little influent for congestion>purposes; at a big international hub things might be a little>different.The procedures will be pretty much the same regardless of the size of the airport. The biggest difference will be if there is ATC, i.e if the field is "controlled". Without ATC, you are more likely to see complete patterns flown. But even with ATC present, if an aircraft is approaching the field from the opposite direction to landing, it is likely that they will be vectored onto some sort of downwind-base-final type of pattern.>Now what does the "12 minute event timer" function on the>onboard clock do for an ailiner like the 747-200?>Is it to be used in the event of a missed approach, and how?No idea, is that something new in FS9/2004? I'm still using FS2002.Mike

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