Heavy / Large classification

Chief Captain

Chief Captain

Well-Known Member
So I've always remembered that large aircraft are over 12,500lb, and heavies are over 255,000lb MGTOW.

However, looking at the AIM Pilot/Controller Glossary, I saw that the numbers have been changed to 41,000lb and 300,000lb respectively. When did that happen?
 
Chief Captain said:
So I've always remembered that large aircraft are over 12,500lb, and heavies are over 255,000lb MGTOW.

However, looking at the AIM Pilot/Controller Glossary, I saw that the numbers have been changed to 41,000lb and 300,000lb respectively. When did that happen?
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It's an ICAO thing for wake turbulence classification. 0-15,499 is light, 15,500-299,999 is medium, and 300,000+ is heavy. I think it was about a year ago with the ICAO 2012 rules.
 
I haven't been in aviation all that long, but light in terms of weight categories has always been less than 41,000 lbs MTOW. I am not sure of the reasoning, but the increase in the heavy category is recent, within the last year and a half or two years.

The <12,500 lb is considered a small, and I believe this number is used when considering aircraft of similar performance characteristics, not wake turbulance
 
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ICAO did that about 2 years ago if memory serves. Large will soon be medium as well.

Helped on my end when a 757 would go from a light 757 to heavy and back 3 times in the course of two minutes, but beyond that.... its awful

On a similar note, conforming to a lesser standard is insane. The big WE, as in pilots, controllers, A&Ps etc in this country do some pretty crazy effective/safe things. Kiss it goodbye soon. We'll conform to standards that we won't have the technology to meet on my end.

Greg, Light was roughly 12,500 to allow for the DC3 if I've been properly taught.
 
genot said:
ICAO did that about 2 years ago if memory serves. Large will soon be medium as well.

Helped on my end when a 757 would go from a light 757 to heavy and back 3 times in the course of two minutes, but beyond that.... its awful

On a similar note, conforming to a lesser standard is insane. The big WE, as in pilots, controllers, A&Ps etc in this country do some pretty crazy effective/safe things. Kiss it goodbye soon. We'll conform to standards that we won't have the technology to meet on my end.

Greg, Light was roughly 12,500 to allow for the DC3 if I've been properly taught.
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Edited post above. I still can't find the exact reference, but they gave us 2 different sets of weights way back in OKC, one was wake turbulance categories and the other had to do with performance I believe. Being oceanic en route, I very rarely have to worry about this stuff, so it has been lost. Always funny to here a DLH or AFR A388 check-in as "super" in their respective accents. I think I have done a CBI about it, but I still haven't found any regs establishing "super" as a weight category.
 
z987k said:
It's an ICAO thing for wake turbulence classification. 0-15,499 is light, 15,500-299,999 is medium, and 300,000+ is heavy. I think it was about a year ago with the ICAO 2012 rules.
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I didn't even see anything referring to 15,500...another number to remember...
 
genot said:
ICAO did that about 2 years ago if memory serves. Large will soon be medium as well.

Helped on my end when a 757 would go from a light 757 to heavy and back 3 times in the course of two minutes, but beyond that.... its awful
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How's it possible to go between categories based on your MGTOW, without the requisite paperwork?
 
It was more like dx filed as a and pilots called it b. Even then it depended on current TO weight. DX goes with a light fuel load they're a 757. Cappy asks for another 2000 pounds of jet a and that could reach heavy threshold. Unless I had to ask on arrival for flow every 75 was a heavy. On departure I asked if they were heavy or not in case it saved a controller down line.

What is this paperwork you speak of?
 
For us, the datatag on 757's indicates heavy/medium automatically.

I'm told it works by the radar measuring the amount of air molecules displaced by the aircraft relative to the density altitude and relative humidity, in reference to the upper level forecasted winds.

and when you're done wiping that off your shoe, every 757 has a little "/" beside the ident, and if they say "We're Heavy" We say "Roger, me too" and carry on
 
genot said:
It was more like dx filed as a and pilots called it b. Even then it depended on current TO weight. DX goes with a light fuel load they're a 757. Cappy asks for another 2000 pounds of jet a and that could reach heavy threshold. Unless I had to ask on arrival for flow every 75 was a heavy. On departure I asked if they were heavy or not in case it saved a controller down line.

What is this paperwork you speak of?
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Heavy is based on your maximum TOW, not actual. I don't see how fuel load can change that number.

You can change the MTOW of your aircraft. My understanding is that all it requires is a (fairly expensive) piece of paper from the manufacturer.
 
Chief Captain said:
Heavy is based on your maximum TOW, not actual. I don't see how fuel load can change that number.

You can change the MTOW of your aircraft. My understanding is that all it requires is a (fairly expensive) piece of paper from the manufacturer.
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It's common from many 757 operators to hear.

"And we're heavy today"

I'm no expert on how they get to that point, but it would seem for some, the designation changes
 
genot said:
It was more like dx filed as a and pilots called it b. Even then it depended on current TO weight. DX goes with a light fuel load they're a 757. Cappy asks for another 2000 pounds of jet a and that could reach heavy threshold. Unless I had to ask on arrival for flow every 75 was a heavy. On departure I asked if they were heavy or not in case it saved a controller down line.

What is this paperwork you speak of?
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It had to do with a higher weight MTOW modification certain carriers had. For example, my former company's 757s had a max takeoff weight of 255,500 lbs, putting it in the heavy category. However, other companies operated theirs at 255,000 lbs. Certain companies had some of both.

As another poster said, it has to do with max weight, not actual weight. We routinely operate empty 767 freighters <300,000 lbs, however, it remains a heavy aircraft.
 
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skypilot6 said:
Lets not forget about "Super" which is only the A380 currently.
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That may change as well.

I have no inside knowledge, but we did have a wake event. A 744 was following a 748 and got waked. Normally, we just cause the wake.
 
Polar742 said:
That may change as well.

I have no inside knowledge, but we did have a wake event. A 744 was following a 748 and got waked. Normally, we just cause the wake.
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"Giant ____ Super" does seem a little pretentious. Right up your alley!
 
@Bernoulli Fan

Would be nice if they included that in the latest .65

Do you remember what I am talking about with regard to performance categories? I remember in basics having a hard time not mixing the two up.
 
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