Preferential Runway Use when no ATC

Is there a prefential runway protocol when operating into a ‘no ATC’ airport?

Yesterday I flew into KSEA and, having monitored air traffic on VatSpy, saw that all aircraft prior to my arrival were using runway 16L (the wind was a consistent 240/04), so I planned likewise. I made my intentions known on Unicom when overhead YVR and also at GRIFY, with a final call when joining the ILS. It was then that another aircraft responded, saying he was lined up on 34R, but would hold position for me to land.

Knowing the surrounding urbanisation, I would also assume that a southerly flow using the runways 16 would be preferred.

I cannot find any guidance as to runway preference during daytime ops at KSEA and wondered if anyone might know RW practice?

Whichever runway is the most suitable for the aircraft you’re operating. Usually it’s the runway most aligned to give you the greatest headwind component.

Often times the airport’s website will publish info addressing noise and how they’re trying to mitigate it. The easy to find stuff is typically for the general public (airport neighbors) but you can usually find something that addresses pilots as well. In the case of SEA, it looks like they prefer to use the 34s during nighttime hours when the winds allow it because much of the region to the north is industry, not residential.

Yes, I am aware of the night preference at KSEA as I indicated.

I was asking if, after my fruitless search, anyone knew of other preferences at KSEA.

And, yes, I am aware of the headwind effect on choice.

As a rule of thumb, any nighttime preferential runway program is likewise preferable during the day. Otherwise, at the big airports, it can complicated because it’s a function of full-time ATC. Some VATSIM ARTCCs publish their controller documents publicly.

So how would he hold position if he was already lined up? :thinking:

I always look in flightaware at the departing/destination airport witch rws are used in real life.If there is no atc I use that rws to .
And i use this if there is no traffic Which runway to choose? The best runway suggestion based on wind
it opens with ENBO but after opening you be able to find the airport you need.

To echo @854822 , I’ll always look up what the real airport is using if that’s available. In the states, digital atis is great for this as most major or large airports use it (I think there are 80 or so airports that do)…you could also use a flight tracker to see what real planes are doing. For small airports I’ll use whatever works for the wind or is best with the terrain.

Sea tac usually lands south for wind calm ops. The issue with flying on vatsim without ATC is you expierence what you came across. I’m not knocking the guy landing north because for all we know he could of been using custom weather and maybe a north landing made sense for him. Kind of a circus without atc. Lol
I found this ATIS site a while back. Might be helpful.


Thanks, Dave,

Your reply agrees with my real-world experience at Sea-Tac (as well as the two aircraft who landed ahead of me on the day in question).

As you say, with no ATC its a bit of a Circus. If our fellow-travellers would just use Unicom a bit more, it would improve everyone’s experience. As I said earlier, why fly on VATSIM if you don’t use the supplied ATC or, as in this case, make better use of Unicom. The aircraft who lined up on 34R only made his first Unicom call once he had lined up - a bit late, really.

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If there is no ATC online, no one can state a preferential/active runway. Pilots can use any runway on their discretion with coordination over UNICOM.

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Particularly in the US, you are so fortunate that you can get the real life ATIS digitally on This is one of the reasons I really like flying in the US.