LiveATC Discussion Forums
Air Traffic Monitoring => Listener Forum => Topic started by: Garry on February 22, 2006, 02:13:28 AM
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Quite often you hear Left Downwind or right downwind what does this mean
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I still cant figure out the exact definitions to downwind, upwind, crosswind, etc. Something simple I should know... Anyone got the answers?
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From the AIM:
http://www.faa.gov/ATPUBS/AIM/Chap4/aim0403.html#4-3-3
1. Upwind leg. A flight path parallel to the landing runway in the direction of landing.
2. Crosswind leg. A flight path at right angles to the landing runway off its takeoff end.
3. Downwind leg. A flight path parallel to the landing runway in the opposite direction of landing.
4. Base leg. A flight path at right angles to the landing runway off its approach end and extending from the downwind leg to the intersection of the extended runway centerline.
5. Final approach. A flight path in the direction of landing along the extended runway centerline from the base leg to the runway.
6. Departure leg. The flight path which begins after takeoff and continues straight ahead along the extended runway centerline. The departure climb continues until reaching a point at least 1/2 mile beyond the departure end of the runway and within 300 feet of the traffic pattern altitude.
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Thats non towered pattern right? Lager class B airports with a tower sound much much different.
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Thats non towered pattern right? Lager class B airports with a tower sound much much different.
It is for an uncontrolled field but the traffic pattern applies to all airports. The only difference at a towered field would be the addition of "left/right" indicating which side the aircraft is on. Left traffic indicates the aircraft is making left turns and right traffic indicates right turns.
It's not that much different at a large airport....some of the legs are simply omitted.
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And almost everyone will call the departure leg the upwind leg when doing closed traffic.
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The only difference at a towered field would be the addition of "left/right" indicating which side the aircraft is on.
This is true at uncontrolled airports as well since many of these airports have "non-standard," right traffic patterns.
In fact, it is good practice at uncontrolled airports to always include "left" or "right" in the leg, just to further clarify one's position.
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And before anyone can think of the question--the names of those legs of the pattern *don't* change when the wind direction changes.
(Warning! Do not read the next sentence if you are easily confused.)
If the wind in JD's picture was blowing from the top of the picture toward the bottom, you'd have a headwind on the crosswind, a right crosswind on the downwind, a tailwind on the base, a left crosswind, on final... :)
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Oh, I guess its just vectors and approachs that confuse me when I listen in. I see on flight tracker they follew the simmilar pattern with legs ommited as you said. What about two runways as in Philly 27R/27L, is there only one active runway at a time on two runways?
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Oh, I guess its just vectors and approachs that confuse me when I listen in. I see on flight tracker they follew the simmilar pattern with legs ommited as you said. What about two runways as in Philly 27R/27L, is there only one active runway at a time on two runways?
Large airports have procedures called flow routes which they reference to vector IFR arrivals into the airport. This is different than a traffic pattern as the vectors usually bring an aircraft to the final approach course. The aircraft all end up on a straight-in approach.
An exception to that would be if the airport was using visual approaches, but even then it would not differ very greatly.
Here is an example of a flow route procedure for PIT which is similar to real world procedures (courtesy of VATSIM). As for Philly, I'm not familiar with their procedures but maybe PHL_Approach or another PHL efficianado can comment.
(http://www.zobartcc.org/pit/west.gif)
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Thanks, Any more insight would help to.
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Oh, I guess its just vectors and approachs that confuse me when I listen in. I see on flight tracker they follew the simmilar pattern with legs ommited as you said. What about two runways as in Philly 27R/27L, is there only one active runway at a time on two runways?
Im not certain about the exact procedures at PHL, but I know most airports with more than one runway will use both of them at the same time. The most common use of two runways being one for arrivals, and the other for departures.
http://www.laartcc.org/charts/KLAX-AD.pdf
At LAX, they will use 24L and 25R for departures and 24R and 25L for arrivals. You can see by just looking at the diagram how it optimizes traffic flow at the airport. Due to a number of factors though, you will often see planes landing on the inner runways and departing from the outer ones.
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(Warning! Do not read the next sentence if you are easily confused.)
If the wind in JD's picture was blowing from the top of the picture toward the bottom, you'd have a headwind on the crosswind, a right crosswind on the downwind, a tailwind on the base, a left crosswind, on final... :)
Digger... you're just a trouble maker now, aren't you! :lol:
JD... thanks for the description with picture, great explanation! :)
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alright, what exactly are vectors, antohor stupid question, better ask now before I make my self look all stupid, If I havnt already!!! :D
Oh and I wasnt looking specifically for Philly procedures, I was looking for something more general as youve shown, thanks guys.
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alright, what exactly are vectors, antohor stupid question, better ask now before I make my self look all stupid, If I havnt already!!!
Vectors are ATC assigned headings that typically have an end-goal, for example:
ATC: "Turn left heading 120, vectors to the localizer"
or
ATC: "Turn right 010, this is a vector around opposite direction traffic."
The headings in the above examples are the vectors, the word "vector" above is just the reason that ATC will typically provide for the heading.
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Digger... you're just a trouble maker now, aren't you!
I do have my moments... :D
As far as "vectors", I'm sure it stems from the mathematical/physics term having to do with the velocity and direction of something. After all, when a controller gives a "vector", those are the things they are controlling.
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alright, what exactly are vectors, antohor stupid question, better ask now before I make my self look all stupid, If I havnt already!!!
Vectors are ATC assigned headings that typically have an end-goal, for example:
ATC: "Turn left heading 120, vectors to the localizer"
or
ATC: "Turn right 010, this is a vector around opposite direction traffic."
The headings in the above examples are the vectors, the word "vector" above is just the reason that ATC will typically provide for the heading.
so that would be on say an ILS approach?
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alright, what exactly are vectors, antohor stupid question, better ask now before I make my self look all stupid, If I havnt already!!!
Vectors are ATC assigned headings that typically have an end-goal, for example:
ATC: "Turn left heading 120, vectors to the localizer"
or
ATC: "Turn right 010, this is a vector around opposite direction traffic."
The headings in the above examples are the vectors, the word "vector" above is just the reason that ATC will typically provide for the heading.
so that would be on say an ILS approach?
It could have to do with any type of approach. You know how Philly North Arrival will even say Vector for a visual. "United 470, Philly Approach, Depart BUNTS heading 100, vector for visual approach 27R, Philly altimeter 3015". Then if you go listen to Enroute they use "vector" often. "Delta 1665, fly heading 170, vector for your descent". "Alitalia 788 Heavy, turn right heading 250, short vector for traffic". Im sure JD would really get into more of the Enroute use of the word and pull some .65 stuff out.
tr.v. vec·tored, vec·tor·ing, vec·tors
To guide (a pilot or aircraft, for example) by means of radio communication according to vectors.
Just pulled that, so really using that word in our case is it's own meaning and not so much as the mathmatical term that digger mentioned.
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so that would be on say an ILS approach?
Yes, it is very common for ATC to vector an aircraft (assign headings to guide the aircraft) to an ILS approach. As pointed out in the previous response, ATC vectors are common for all types of instrument approaches, including VOR, GPS, localizer, NDB, and back course localizer approaches.
Vectors are also commonly used when guiding departing aircraft away from the airport and to their first fix/waypoint along their route.
For example, "United XXX, turn left one-two-zero, when able, direct SPARTA."
In this case, the heading of 120 will put the aircraft on more or less a direct route to the VOR called SPARTA, however, whenever the pilots are able to pick up the VOR on their own, they are free to leave the ATC assigned heading and steer their own course to the VOR.
And finally, vectors are commonly used by ATC for aircraft spacing as well.
"United XXX, turn right 090, vectors for spacing around traffic during the climb."
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Just pulled that, so really using that word in our case is it's own meaning and not so much as the mathmatical term that digger mentioned.
My point was that mathematicians and physicists were using the term while Orville and Wilbur were still bicycle mechanics, and it meant exactly what it still means in both cases. No adaptation was required to make it a useful term for the control of air traffic. (Otherwise, somebody would've had to concoct yet another acronym.) :)
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Thanks alot guys, that makes alot more sense now that I think about it. I havn't started my flight training quiet yet so I not sure what some stuff is yet. Thaks again.