June 21, 200520 yr The reference you are looking for is this (at least in the US):http://www.faa.gov/atpubs/ATC/Appendices/atcapda.htmlAnything with an "H" is a "heavy" and it primarily has to do with safety.ATC needs to know for a number of reasons, here are the main ones:- separation for wake turbulence (2 minutes behind any heavy under normal conditions, longer depending on weather and local procedures) - this can vary with traffic and local airport procedures, discretion of the ARTCC chief)- handling in airport controlled space, most heavies need a lot of room to turn and change altitude or speed- heavies use different runways (load, length) for t/o and landing, especially if the airport has more than one active runway- tells other pilots in the area not to mess with you - not kidding - size does matter in airport controlled space - a 747 can toss a small craft like a leaf, one major worry is VFR flights in controlled spaceGTOW is not the whole story, as the 757 and sister ship 767 qualify as heavies, as do the concorde not so much because of the weight but because they cause wake turbulence similar to a 747. 757 pilots do have the option of not using the "heavy" designation (reminds me of some of my fellow drivers on the road and their use of turn signals - they know where they are going so why use them?), and will be part of the flight plan filing process.Cheers,
June 21, 200520 yr >The reference you are looking for is this (at least in the>US):>>http://www.faa.gov/atpubs/ATC/Appendices/atcapda.html>>Anything with an "H" is a "heavy" and it primarily has to do>with safety.>>ATC needs to know for a number of reasons, here are the main>ones:>- separation for wake turbulence (2 minutes behind any heavy>under normal conditions, longer depending on weather and local>procedures) - this can vary with traffic and local airport>procedures, discretion of the ARTCC chief)>- handling in airport controlled space, most heavies need a>lot of room to turn and change altitude or speed>- heavies use different runways (load, length) for t/o and>landing, especially if the airport has more than one active>runway>- tells other pilots in the area not to mess with you - not>kidding - size does matter in airport controlled space - a 747>can toss a small craft like a leaf, one major worry is VFR>flights in controlled space>>GTOW is not the whole story, as the 757 and sister ship 767>qualify as heavies, as do the concorde not so much because of>the weight but because they cause wake turbulence similar to>a 747. 757 pilots do have the option of not using the "heavy">designation (reminds me of some of my fellow drivers on the>road and their use of turn signals - they know where they are>going so why use them?), and will be part of the flight plan>filing process.>>Cheers,>>Mr Martin, from your link "AIRCRAFT WEIGHT CLASSES a. Heavy. Aircraft capable of takeoff weights of more than 255,000 pounds whether or not they are operating at this weight during a particular phase of flight. b. Large. Aircraft of more than 41,000 pounds, maximum certificated takeoff weight, up to 255,000 pounds. c. Small. Aircraft of 41,000 pounds or less maximum certificated takeoff weight."Best
June 21, 200520 yr >So i suppose they put questions on it in several JAA ATPL>exams (including comms) just for a joke? ;-)Yes because if you were to fly to foreign contries where that phraseology is used it would be handy to know what it means!
June 22, 200520 yr as real life ATC at Washington Center - Heavy is required usage in the Terminal environment. Usage in the Center environment stopped about 10+ years ago. Continental flies 757s that file as 'heavy' (I believe the 300 series). The heavy usage is required regardless of actual weight, Ross is right, it is the capable of part. Also, heavy used to be 300,000+ and was lowered after several encounters to the current 255,000+. I worked the NASA flight with a 757 and 737 many years ago doing tests on the 757 wake off of the VA MD coast.as an aside - I had a G4 pilot lose total control of the aircraft one hot summer day at about FL310. He was climbing out 10 miles behind a B752 in still air. We had no turbulence reports at all. Totally smooth air. Pilot calls screaming he's in severe turbulence and can't control the aircraft. This lasted for about 15 seconds. After everyone calmed down (and he got control of the aircraft) we figured it was the wake from the 757. He said the plane was rolling 60 degrees left and right at the time. also, I've noticed that the A340 in certain conditions puts off really intense wake that in the right atmospheric conditions lingers longer than most. (aircraft 2000ft below and several miles behind getting 'chop' when air has been reported smooth)
June 22, 200520 yr I belive that settles it then ;)http://www.precisionmanuals.com/images/forum/800driver.jpg Cheers,Victor M. Lima
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