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Consider Homestead Airport, a fictional paved, non-towered airfield in the exurbs of Bigtown, USA that has become popular as a home field for recreational pilots. The airport's busy enough that addressing "Homestead traffic" on MULTICOM any given daylight hour isn't just talking to yourself; there will be at least one other plane in the pattern and a couple more on the ground, however there isn't enough traffic yet to justify hiring ATCOs to run the field. The sole runway is 13/31.

On the Saturday in question, there's a southeasterly wind at sunrise and so traffic starts the day using runway 13. However, the wind suddenly changes just after noon as a norther blows through, such that the five or six aircraft currently in the traffic pattern now need to use runway 31.

What is the standard procedure, if any, to establish the new traffic pattern at the airfield given the wind change? I'm especially curious as to how traffic already in a pattern for the now-downwind runway would be expected to maneuver to establish the new pattern, especially if the segmented circle or AFD indicate traffic should stay to one side of the airport regardless of runway direction (for instance a left-hand pattern on runway 13 but a right-hand on 31, to keep traffic away from a developed neighborhood to the southwest).

Bonus question: At the time a transition to the new runway direction is needed, there is an aircraft holding short for runway 13, with another behind him. These aircraft need to taxi down to the other end of the airfield, and quickly, or they'll be staring at the nosecones of exiting planes. There is a single taxiway, too narrow to 180 on especially with other aircraft using it, and the nearest runway exit is halfway down the field, so aircraft on the ground must taxi down the runway in the opposite direction to get to the correct end. What radio comms are recommended/required to advise traffic in the pattern that the runway has taxiing traffic?

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  • $\begingroup$ This sounds a tad specific to have been made up on the spot... ;) $\endgroup$ – FreeMan Sep 23 '15 at 19:58
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    $\begingroup$ It's a question I've been thinking about for a while, since I first heard that pilots coordinate to do this. I'm most interested in whether there are any predefined maneuvers that pilots should know to manage the transition, like "all aircraft on downwind leg should make a one-minute 180 away from the airfield at the point where they'd normally turn base, then proceed downwind and turn base at the other end". $\endgroup$ – KeithS Sep 23 '15 at 21:19
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Your example is too specific to be useful to others, so let's consider the general case instead.

At an untowered field there is no "active" runway - they're all active.
There is usually a "preferred" runway - the one best aligned into the wind - but any runway can be used by any aircraft at any time, subject to whatever safety considerations the pilots mutually agree on. (At untowered fields with intersecting runways that have a lot of training on the field it's not uncommon to have traffic on the crosswind runway intersecting the preferred runway when students need to practice crosswind landings. It can be coordinated safely with a little cooperation between the pilots involved.)

The runway is "changed" by pilots announcing they're using a different runway. There may also be a unicom operator at the field who announces a change in the preferred runway and lets incoming aircraft know about it.
Usually pilots who are already in the pattern for the "old" runway will complete their circuit and land, clearing the runway as expeditiously as possible.
Similarly pilots waiting at the threshold when the wind shifts may elect to either make their takeoff from where they are, or taxi around to the new preferred runway. (In a case where the aircraft must enter the runway to turn around, or where they must back-taxi on the runway this obviously needs to be coordinated with the other pilots. The standard phraseology to use for this is "N12345 back-taxiing on runway XX" )


To your specific example, the directions of traffic patterns don't really matter much: As I mentioned aircraft already in the pattern will probably complete their circuit and land on the runway they were lined up for. Even in the case of Left Traffic for 13 and Right Traffic for 31 and two aircraft maneuvering to enter the pattern for opposite runways the standard pattern entry (45-to-downwind) will tend to keep airplanes apart (they won't ever be heading at each other in the downwind leg if they enter it on the 45, and it should at least ensure they see each other in the opposite-direction 45 and can coordinate to ensure they're never flying at each other). One airplane will probably have to extend their pattern to allow the other to clear the runway safely before they can land, however.

Traffic really should not really be arriving to both downwinds simultaneously anyway, particularly in your example with a single runway: Inbound aircraft should coordinate to arrive in the pattern for the preferred runway.

Aircraft already in the pattern have two choices: Land downwind if safe, or depart the pattern and re-enter it to land on the new preferred runway. A downwind landing must obviously be coordinated with aircraft which may be preparing to depart in the opposite direction.
If landing downwind is unsafe (due to wind speed) or otherwise undesirable (e.g. due to other traffic) climbing above pattern altitude, leaving the area, and returning via a standard pattern entry for the opposite runway is usually the safest course of action.

Aircraft waiting to depart also have two choices: Depart downwind (which must be coordinated with aircraft arriving to the preferred runway), or taxi to the preferred runway end for takeoff. In cases such as you've described where back-taxiing is necessary this must be coordinated with pilots landing (in either direction) as the back-taxiing aircraft will be occupying the runway they need for landing.


The major complicating factor you didn't specifically mention, but which is implied by multiple aircraft "in the pattern" is closed traffic (aircraft making touch-and-go or full-stop/taxi-back landings and immediately taking off again).

Full-Stop/Taxi-Back landings are not a problem: Much like "regular" landing traffic they can land downwind, and upon exiting the runway taxi back to the preferred runway end for their next takeoff.
Touch-and-Go aircraft have two main choices: Land downwind as a full-stop and taxi around to the preferred runway end (which is probably the safest and most considerate thing to do), or complete a touch-and-go with the intention of departing the pattern and returning to set up for circuits to the new preferred runway.

Another important consideration are aircraft without radios (NORDO)- yes, these do exist). A visual scan of the traffic pattern is required at any uncontrolled field at any time to ensure you are not conflicting with NORDO aircraft.
These are often slower planes, so having one in the pattern landing "the wrong way" may require you to wait a while for them to complete their circuit before you can begin operations on the new preferred runway.

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This is complex and unfortunately can create a dangerous situation. I fly out of KDYL and have seen a similar situation occur. Generally what I see is not that the wind changes but that there is no wind so both directions are used. The fact of the matter is, at an untowered airport the runway choice is up to you unless specific conditions are specified in the AF/D. The problem is that many people forget that or simply do whats easiest. At DYL the calm wind runway 05 which is great if you are departing to the east or north but I have seen plenty of people use 23 on calm days to depart to the south and west. Landings are generally justified similarly and people will enter the patter that best fits the flight path they are on. That being said when I fly in and I hear people calling legs of a particular pattern I will go for that as its the assumed pattern at the field. Remember it is your job to observe the flow of traffic as you would if you lost radio communications. If you feel the wind favors the pattern that is not being used you can wait until everyone is on the ground and announce your intentions for the other pattern.

In regards to your bonus question if you decide to taxi back (go down the runway to the other end) on the active you should not do so unless there are no approaching planes. Likewise once you have stated you have entered the active for a taxi back (and announced as such) no one else should be taking the active from the other end to take off. You should not be entering the active for taxi back if anyone is on approach unless the taxiway at the other end is free to leave the active in time. Thus you SHOULD NOT encounter other aircraft but people are people so that does not mean you WILL NOT encounter them.

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