Originally posted by UAL Traveler:
fastflyer is correct. The heavy designation is generally assigned to aircraft with gross weights in excess of 300,000 lbs. That includes the wide-bodies, and excludes the narrow-bodies.
The "technical" definition of "heavy" -- yes, I sort of got a bee under my bonnet and did a little more research -- is:
AIRCRAFT CLASSES- For the purposes of Wake Turbulence Separation Minima, ATC classifies aircraft as Heavy, Large, and Small as follows:
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.
Source:
http://www.faa.gov/ATPubs/PCG/pcg-a/pcg-a.html#AIRCRAFT CLASSES