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Traffic Patterns

PostPosted: Mon Feb 27, 2006 8:22 pm
by cheesegrater
What kind of traffic patterns do airliners fly? I know general aviation aircraft fly those rectangular patterns. Is it just a straight in approach for an airliner? What if they cannot land at the moment and have to stay in the air? I suppose it depends on the area, as big cities may have many airports in close proximity.

Re: Traffic Patterns

PostPosted: Mon Feb 27, 2006 8:52 pm
by beefhole
Well, it depends-is the airliner flying a STAR (which it most likely is) or is it being vectored in directly by ATC?

In FS, ATC will put you in a traffic pattern-if you approach Atlanta from the west and runway 27R is active (landing to the east), ATC will put you on a downwind and have you turn on a base for 27R.  In real life, when STARs are being used, patterns are generally not flown-the aircraft flies to a given point where they begin their final approach. However-if, for example, the tower decides to change the runway just as you turn on final (which has happned to me once before in FS, more times than I care to remember IRL), you will be told to "make left traffic for runway 9L", etc.  In that case, airliners DO fly a normal pattern, albeit much higher and further out ;)

I was pretty much wingin that, if anyone can give something more accurate please do.

Re: Traffic Patterns

PostPosted: Mon Feb 27, 2006 10:01 pm
by Brett_Henderson
That's pretty close, but nothing is carved in stone. Standard approaches (STARS) can start as far out as 100nm and there's always one, if not a few hold fixes. There are usually a set of STARS (or one STAR with a few versions) for each active runway to accommodate traffic approaching from all directions. When spacing becomes a problem.. ATC asks a plane to hold..or.. can expidite him from a point on the STAR directly to the runway... or  alert him that he'll be flying vectors period (which could very well include a downwind/base).

If everything goes well.. the whole point of STARS is to make it all efficient.. It's awfully expensive for a 777 to fly pretty much to an airport and then fly a few miles out and back in some sort of "jet-sized" pattern.

I was on a US Airways Dash-8 into Pittsburg last year and I swear we flew a tight downwind and then the turn to base/final was all one motion.. barely lining up with the runway at the numbers. I'd have loved to have heard THOSE vectors..

Re: Traffic Patterns

PostPosted: Mon Feb 27, 2006 10:07 pm
by beefhole
Standard approaches (STARS) can start as far out as 100nm and there's always one, if not a few hold fixes. There are usually a set of STARS (or one STAR with a few versions) for each active runway to accommodate traffic approaching from all directions.

Right Brett, I was simply trying to point out in my post that you almost always head from a fix to the runway, as opposed to being vectored to the runway by ATC.

I've also had a Dash flight fly a pattern like that, on a turbulent winter day into PHL.

Re: Traffic Patterns

PostPosted: Mon Feb 27, 2006 10:39 pm
by Brett_Henderson
They must have a reputation as pretty nimble aircraft.. able to duck in quick and get off the runway..

Re: Traffic Patterns

PostPosted: Tue Feb 28, 2006 4:44 am
by C
I swear we flew a tight downwind and then the turn to base/final was all one motion.. barely lining up with the runway at the numbers. I'd have loved to have heard THOSE vectors..


Who needs a base leg anyway. The last time I flew a base leg was in 1999! ;D

(By way of explanation, the circuit/pattern we fly is an oval) ;)

EDIT:  Here's a good one. Plenty of holds and info..


Lol. There's a good one I saw for one of the Norwegian airports (I think). The whole TAP was like a spiders web of holds and fixes! I'll see if I have a copy I can scan... One of the reasons I'm happy not flying transport aircraft just yet! ;D

Re: Traffic Patterns

PostPosted: Tue Feb 28, 2006 8:05 am
by Nexus
a STAR doesn't really have anything to do with the pattern, as seen by the Arrival procedure posted by Brett, and there were some nice holds there  ;D

The pattern is usually described on approach charts, from the IAF to the FAF.

Re: Traffic Patterns

PostPosted: Tue Feb 28, 2006 10:41 am
by Brett_Henderson
The pattern is usually described on approach charts, from the IAF to the FAF.


A cessna 172 isn't going to start his arrival at Cincinnati some 15 miles NE of Columbus (110nm out)  :P ...  and a 777 isn't going to fly an approach chart that has him turning abruptly 90 degrees at the outer-marker ;)

The only approach chart that I can think of that even sugests a traditional pattern would be a VOR-A where you look for the airport and then circle to land (pick the best runway(maybe fly a leg or two (or three)) of a pattern).

If the tower doubts that they can get a jet to the runway, relatively straight in.. they'll make it hold somewhere along the STAR.

If a 172 intends to land at a busy airport, he will file (or announce(or be given)) a published approach, but he'll be vectored all the way in. IAF / FAF and all that stuff (and missed procedures) and a pilot's responsibility to fly it, would matter if radio communications were lost. I can't imagine a scenario where a small, GA plane would just be cleared to land and decide for himself to follow the plate. Same thing for the 777 (if he even could).

Re: Traffic Patterns

PostPosted: Tue Feb 28, 2006 11:40 am
by Nexus
I thought the original question was about commercial airliners, not general aviation.
Therefore, what the little c172 does is rather irreleveant in this case :)
But you're correct in your assesment, but it

Re: Traffic Patterns

PostPosted: Tue Feb 28, 2006 11:58 am
by Brett_Henderson
Yeah.. original questions seem to fade quickly around here..lol