FlyerJosh,
Originally Posted by FlyerJosh
Refresh my memory what classifies as small / large and where the line is. IIRC its 41K right? For some reason I thought it was 3 behind large, 5 behind heavy. But now that you mention it 4 seems to ring a bell.
From the Pilot/Controller Glossary:
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.
It's interesting to note that these classes have changed over the years. It seems that certain aircraft companies have had some influence over the process. Two that come to mind are the SF340 and the B757. Both have been in different classes for wake turbulence separation at one time or another, however I don't recall if the actual
class criteria was changed, or if the aircraft
maximum certificated takeoff weight was changed.
Also, the B757-300 is considered a
Heavy.
MEM_ATC