Hi all, I'm flying the PMDG 737 NGX and was wondering which option to select on RC, 'Heavy' or 'Jet' and does it make any difference at all? Also, I have noticed that at A LOT of airports (Dublin for one) that when I get to the holding point, the AI plane lines up to the runway but refuses to take off, it just sits there. However, when I'm still at the gate, I can see the airplanes lining up and taking off without any issues. Thanks.

I don't have the NGX, but here are the ICAO rules... "AIRCRAFT WEIGHT CLASSESa. 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."

Jet. As a rough rule of thumb, narrowbodies are not Heavy, with the strange case of the 757-300 and the being an exception, as far as I have understood it.

RC uses those names but uses turbo-prop or prop in the lower ratings based on performance. in RC4 a 'heavy' other than in FAA territories can be granted departure speed relief from the 10,000 foot and local airport speed limit. It indicates to a controller that greater separation is required as well. The 737NGs are all rated as jets. You can find the maximum take-off weights in the table in this article: http://en.wikipedia.org/wiki/B737NG

I don't have the NGX, but here are the ICAO rules... "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."

Actually the FAA changed that in the US, because of the confusion caused by the different weights of the 757. This is the new rule CHANGE:OLDAIRCRAFT CLASSES - For the purposes ofWake Turbulence Separation Minima, ATCclassifies aircraft as Heavy, Large, and Small asfollows:a. Heavy- Aircraft capable of takeoff weights ofmore than 255,000 pounds whether or not they areoperating at this weight during a particular phaseof flight.b. Large- Aircraft of more than 41,000 pounds,maximum certificated takeoff weight, up to255,000 pounds. NewAIRCRAFT CLASSES - For the purposes ofWake Turbulence Separation Minima, ATCclassifies aircraft as Heavy, Large, and Small asfollows:a. Heavy- Aircraft capable of takeoff weights of300,000 pounds or more whether or not they areoperating at this weight during a particular phaseof flight.b. Large- Aircraft of more than 41,000 pounds,maximum certificated takeoff weight, up to butnot including 300,000 pounds. http://www.faa.gov/d....525%20%20A.pdf