While flying from San Fran to Chicago last week, I got to ride a 777 for the first time. (Nice plane!) Being the hungover, dork that I am, I spent much of the flight listening to the various ground controllers talking to the aircraft in the area, including mine*. Our aircraft was referred to as a “heavy” by both the pilots and ground control. (Specifically, we were United 138, heavy). A few other aircraft were also “heavies”, but not many.
So what’s a “heavy”? The larger of the aircraft up there? Why the designator? What does that tell ground control or other aircraft? More wake turbulence?
*If you ever want to push your fear of flying over the edge, listen to the ground controllers on approach to Chicago. From the sounds of it, it’s a miracle we didn’t slam into about 40 other planes. Quite the ballet going on up there.
You got it. More wake turbulence which means different seperation requirements for following aircraft. I’m not sure what the weight cut off is for a “heavy”. A B747 is heavy, a B737 is not.
The airline pilots of the SDMB should be able to provide more details.
Getting various answers off Google, but from what I can glean, a “Heavy” is an aircraft capable of taking off with a weight of 255,000 pounds or more (even if it isn’t actually taking off at that weight), and which requires other aircraft to keep at least two minutes behind it due to wake turbulence.
Other aircraft are classified as either “large” or “small”.
Thus, a “heavy” aircraft includes B747, 767, 777, A300, 310, 330, 340, (380), Concorde (though it’ll never fly again), and many of the larger military aircraft. The Boeing 757 has a max. take-off weight of right around 250,000 lbs, thus it has the same wake turbulence spacing as a “heavy”, but controllers don’t usually add the “heavy” suffix to the plane’s callsign.
IANAP, but I believe the term “heavy” came into use when the jumbo (also called wide-body) passenger jets first appeared, and has been used for them ever since.
Thanks all - that all makes sense. When we were close to, or on final, ground control notified us of an American “heavy”, (x) number of miles ahead of us, and “be warned of wake turbulence”.
I don’t know how much them boys and girls working the approaches to Chicago get paid, but it probably isn’t enough.
Planes that have a headset connection in the armrest often let you listen in to the pilots on one of the available channels. However, I think he meant air traffic controllers instead of ground controllers. A ground controller, AFAIK, manages the traffic of planes taxiing on the ground, which is a separate task from air traffic control.
ATC handles aircraft en route. Ground Control handles aircraft on the ground at the airport. The control tower (which contains ground control) handles aircraft within the airport’s airspace.
Right. The 747 and DC-10 produce much stronger tip vortices than any other airliner had until that time. A tip vortex is the spiraling airflow, essentially a horizontal tornado, created by higher-pressure air under the wing flowing around the tip to the lower-pressure area above it. Consequences of hitting one in a smaller plane can be severe. You may have heard of the mysterious phenomenon called “clear air turbulence”, but that’s actually just wake turbulence created by tip vortices. There’s a pic somewhere of a B-52 that had its tail torn off by hitting another airplane’s wake, for instance, and the AA A300 crash at JFK a couple of years ago was initiated by a wake turbulence encounter.
As a result, the FAA introduced longer spacing requirements behind heavies than for other planes, to allow their wake turbulence to dissipate to “normal” levels before the next plane could hit it. That’s why the radio call from a heavy’s crew - it warns controllers to leave more room behind them, and warns other aircraft too. There was some discussion about creating a “medium” category for the 757, which for some reason produces much stronger tip vortices than would be expected for a plane its weight, but that hasn’t happened.
Yes, I should have said Air Traffic Controllers, vice Ground Controllers.
As was mentioned, I was able to listen in on the headset, Ch 9. Just before the flight, the co-pilot announced this in his pre-flight announcement. I never realized that aircraft were always in contact with various controllers along the way. I guess I just figured they only used them on departures and arrivals. Pretty interesting stuff - especially on the approach.
Although wake turbulence can be turbulence in clear air, it is not the source of all “clear air turbulence”, which can also be generated by mountain waves, jet streams, and various other things.
Although the 757 is not, technically, a heavy pilots are cautioned to treat them as heavy in regards to wake turbulence, and I’ve yet to find myself under air traffic control and behind one (waaaaaaaaaay behind one!) without getting the “wake turburlence” caution repeatedly.
One of the big iron pilots can correct me if I’m wrong on this, but over North America a passenger jet with passengers is always in contract with air traffic control, either US, Canadian, or Mexican. You wouldn’t get out of contact with the controllers until you go pretty far out over the Atlantic or Pacific.
Gotta be. In cruise, they’re pretty much always above 18,000 MSL, which is Class A airspace and IFR only by definition. Below that, they’re in either approach or departure phases, which sorta also implies controller contact. I don’t know of any airline service to an uncontrolled field in the US.
IANAP, but the NTSB reports that I’ve read confirm the first part of your statement. They were always in contact with a controller, right up until the # on the CVR for ‘expletive’.
This document indicates that for the Atlantic, there is still seamless communication capability via HF radio, if I’m interpreting it correctly.
Airline service to uncontrolled fields isn’t too uncommon. I was looking for a flight into the tiny Page, AZ airstrip the other day and found that Frontier flies there regularly. That got me looking at some route maps and I found several other uncontrolled airports with scheduled service.
I’ll confim what Berkut said - airline service to airports without towers (which what “uncontrolled” means, for you non-pilot, non-controller types) is pretty common in the US. However, just because there’s no tower on the field doesn’t mean the pilots aren’t in contact with air traffic control. Untowered fields needing air traffic or instrument flight services are assigned to a control facility that will manage that sort of traffic to and from those fields.
It’s entirely possible that the passengers are unaware of the lack of control tower at a field, since the procedures don’t differ much, if at all, from their perspective.