Simviation Forums

Just a quickey going out to all the more aviation enlightened people out there, I have always wondered what is the correct usage of the sufffix 'Heavy'

Eg. "Delta 246 Heavy, you are cleared for take off RW18"

I just presumed this indicated the aircraft was fully loaded/fueled/both. Just wondered if anybody could clear up this little bit of trivia for me

JB (always learning)

I always thought that aircraft with "Heavy" added to their callsign were anything large (e.g. anything larger than an A318, A319, A320, A321, and all kinds of 737)...  :-?

that would be a good explanation, however in the aircraft selection prompt (fs9) you can chose whether you would like a 'heavy' designation by ATC, thereby meaning you could have a heavy cessna! or a un-heavy 744!?

confusing!!! lol

JB

it is to designate the aircraft that cause large amounts of turbulence. the 757's unusually powerful engines also give it a heavy designation.

it is to designate the aircraft that cause large amounts of turbulence. the 757's unusually powerful engines also give it a heavy designation.

Ah, I see - thanks Craig, I was wondering why 757's were assigned the "heavy" callsign as they themselves aren't really that big...

Actually I do believe it is determined by takeoff weight isn't it?  I'm not sure what the threshold is for the heavy designation though.

I think the Heavy designation starts at 255,000 lbs.

It's an old traditional phrase coined by 'surfer dude' pilots that weren't looking forward to the flight, as in "Wooagh, heavy man" - it has since been shortened to 'heavy' in an effort to keep busy communications frequencys free of 'surf talk' - man 8-)

See you at the beach dudes

TSC.

Hmmm I can't find much around. I too wondered where was the right time to say heavy.

However, this site was an interesting read.
http://www.faa.gov/ATPubs/AIM/Chap7/aim0703.html

Officially, "heavy" as regards ATC parlance refers to aircraft which, at the time they are being handled, weigh over 300,000 lbs. gross.

There may be some airliners that have legally operational weights below 300,000 but GTW or GLWs at or above 300,000, which would explain the ATC option in FS9.

I've yet to hear any arriving airliner not referred to as "heavy" by the crew or controllers in all the time I've been monitoring my local approach and tower freqs, however.

Generally, "heavy" is the only weight reference made in ATC communications... not sure why, exactly, as any airliner is obviously heavy enough for concerns about wake turbulence, etc., whereas an inexperienced light-single pilot flying into a controlled field may not realize that that loaded Caravan or Gulfstream in front of him is heavy enough to upset his little trainer with its wake turbulence...

Here's a weight-reference list from some ATC training pdf. I found online:

it is to designate the aircraft that cause large amounts of turbulence. the 757's unusually powerful engines also give it a heavy designation.

Actually it's the wing design, not the engines-I said that a while back and Nexus corrected me.

it is to designate the aircraft that cause large amounts of turbulence. the 757's unusually powerful engines also give it a heavy designation.

Actually it's the wing design, not the engines-I said that a while back and Nexus corrected me.

It's the weight. Wingtip vortices (which are the most dangerous component of aircraft wake turbulence, although not the only component) are almost entirely dependent on weight, in terms of their intensity. Wings can be designed to minimize the effect somewhat (and yield better cruise efficiency), but in most cases, it's all about gross weight, not wing shape or length.

Airspeed figures into it only because when climbing or descending, the ratio of weight to lift and thrust to drag changes, causing much more kinetic energy to be released at the wingtips than during cruise, when the wing isn't working quite as hard. And a wing works hardest when it has a heavy load and not much airspeed to help generate lift.

With flaps down, the wing now has more camber, and will get more lift with less airspeed, and the energy of the wingtip vortices will be reduced somewhat. This is why the most dangerous tip vortices are off slow, heavy planes in a clean configuration... such as climbing out or intital descent just prior to lowering gear and flaps.


http://en.wikipedia.org/wiki/Wingtip_vortices

I thought wingtip vortices were a direct product of lift?  Thus higher weight means higher lift, which means larger wingtip vortices.

It's the weight. Wingtip vortices (which are the most dangerous component of aircraft wake turbulence, although not the only component) are almost entirely dependent on weight, in terms of their intensity. Wings can be designed to minimize the effect somewhat (and yield better cruise efficiency), but in most cases, it's all about gross weight, not wing shape or length.

Either way Rotty, as far as I know, ALL 757s get the designation 'heavy', regardless of weight.

It's the weight. Wingtip vortices (which are the most dangerous component of aircraft wake turbulence, although not the only component) are almost entirely dependent on weight, in terms of their intensity. Wings can be designed to minimize the effect somewhat (and yield better cruise efficiency), but in most cases, it's all about gross weight, not wing shape or length.

Either way Rotty, as far as I know, ALL 757s get the designation 'heavy', regardless of weight.

Just discovered that max GTW for 75s is under 250K... hmmm.
Well, at any rate, 300,000, 225,000- if it weighs more than the plane I'm flying, I'll stay the hell away from the wake!!  :D