Why do air traffic controllers call aircraft 'Heavy'?

Question

I've been watching some documentaries with my b/f and we wondered why sometimes an aircraft is sometimes called 'heavy' somewhere in it's callsign - any ideas ?

Answer 1

Taken from Appendix A of the FAAO 7110.65R "Air Traffic Control"

"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."

Any aircraft that is classified as a heavy in this manual must use the word heavy when communicating with airtraffic control on or near the airport, with the exception of the Boeing 757, which also must use "heavy". The use of the word "heavy" may be ommitted when an aircraft is operating within the en route envirnoment, aka "center".

Notice the word "capable" above. Even if a heavy aircraft does not weigh more than 255,000lbs at takeoff, it still must be referred to as a "heavy". Also, in other parts of the world besides the U.S., the weight limit is 300,000lbs if memory serves me correctly.

Answer 2

All of the above are true but that's not why aircraft are called heavy. Its to do with the amount of turbulence at low level the aircraft produces, in the trade its known as wake turbulence. All of the communication between aircraft and the ground is done by radio and often, controllers and other pilots cannot see the aircraft concerned. The amount of distance between aircraft or spacing is directly proportional to the size of the aircraft. When the flight plan is filed the pilots append the suffix heavy rather than the controllers. As the flight progresses everyone who hears the call-sign knows that they are dealing with a potentially dangerous situation if they get too close or indeed, if they let another aircraft get too close. To give you an example, a light aircraft following a jumbo jet onto a landing runway in the UK would need to be a minimum of 4 miles and preferably 8 miles behind it to avoid being flipped over. That's why.

Answer 3

Heavy Aircraft

Answer 4

Lew W has it just about right. However it's not ATC that use the suffix, it's the crew. I believe it's mandatory in the US but not in Europe. The reason the word is used is to indicate the Wake Turbulence Category, that is the amount of vortex generated by the wingtips which is of great significance to following aircraft particularly if they fall into the Light or Medium WTC categories. A B737 following a B747 could easily be inverted, causing the crew to lose control of the aircraft. The B757, although classified by it's weight as a Medium aircraft was found ,shortly after it entered scheduled service to have similar WTC characteristics to a heavy aircraft by virtue of it's aerodynamic configuration and was subsequently reclassified as a Heavy jet to protect lighter following aircraft.

Answer 5

Lew W is the ONLY correct answer.

Very simply, large aircraft are less manouverable but more significantly they leave a large wake votex (bumpy air behind them) which will adversely affect following aircraft. The callsign suffix 'heavy' indicates that to the controller so he can make due allowances for the following flights. It's an effective shorthand.

Answer 6

All aircraft over a particular size and weight, such as a 747,L1011 Tristar,Mcdonnell Douglas DC10 and larger military aircraft like C5's and Starlifters are known as Heavies.

Answer 7

It is any airplane with a capable takeoff weight of 225,000 lbs or more. I think the 757-300 is considered a heavy and anything bigger than that (B767, B777, A330, A340, etc.). Basically the reason for calling them 'heavy' is the alert other aircraft in the area of wake turbulence which can be dangerous for smaller planes.

Answer 8

It basically makes it clear that it's a larger aircraft and requires a longer runway on which to takeoff and land.

Answer 9

This indicates the aircraft size, so a MD11, DC10 747 etc would be called heavy, where as a 737 would not

Answer 10

Hi Honey,
Er, ever heard of "light aircraft" ?
Same radio talk thing between air & ground.
If I am whizzing around in my friends' Cessna 152, we are "light aircraft, call sign such & such"
When he does his job fying for Easyjet, He will remember to say "So & so - heavy"
Simple as that really.

Bob the Boat,
Heavy, as the boat weighs about 11 tons.