PHX Operations Question...

[JALTO]

I've been staying at a airport hotel in Phoenix on and off the the last 2 months for work and have noticed that in the morning they are running the 8/7's operations but then around noon (quessing here because I'm not near the hotel at this time) the operations switch to 25's/26 and run that way through the evening. 

I understand the concept of planes using certain runways for the winds....PHL which is my home airport uses 27R most days except when weather rolls in they switch to the 9's.  If anyone is familiar with the Phoenix area you will know that the only weather they have this time of year is sun and hot! 

So if anyone has knowledge of why PHX runs one operation in the morning and another in the afternoon/evening please share with me....if it is just a coincident please let me know that too.

Thanks,
Jalto

[cactushp]

Its like that nearly everyday. The winds shift pretty regularly from the east in the morning to from the west in the afternoon. Nothing unusual. 

[DairyCreamer]

Aside from Mr. HP's wind-related observation, I recall a discussion with a controller at P50 where they said their brothers in the tower were whimps and didn't like looking in to the sun when clearing people to land 

~Nate

[tyketto]

Its like that nearly everyday. The winds shift pretty regularly from the east in the morning to from the west in the afternoon. Nothing unusual. 

Perhaps LH can chime in on this as well.

How does density altitude play a role at PHX? I know at LAS, which is about the same elevation MSL, sometimes it is high enough to cause the 7s to be used instead of normal ops on the 25s, even if winds are calm. How does that work in PHX?

BL.

[DairyCreamer]

From a practical standpoint, west flow is very slightly downhill (about a .2% gradient) for all the runways.  I don't imagine this affects airline's performance calculations much since it is such a small change though.  In LAS, the gradient is right about 1.0% it looks like, far more significant for performance calculations, and changing to the 7s for departures would be a big help.

For PHX, the little gradient combined with the west winds in the afternoon though, on days where the density altitude climbs to 5 or 6,000 feet, every little bit helps.  It really sucks when the airlines start going weight restricted.

I would think too you would get a few more requests for 26 departures given the extra 1189' she has.  Again, not much, but better than nothing.

~Nate

[LHP50]

Ok, since you asked... the runway direction at PHX is primarily affected by two factors: wind and noise abatement.  The wind in the valley is usually out of the East in the morning and out of the West in the afternoon.  Meteorologists explain it is caused by the mountains and heat convection.  A long, long, time ago the cities of Phoenix and Tempe reached a noise abatement solution to balance the increased noise of departures over arrivals.  Basically it was agreed that operations would be split 50-50 between East Flow and West Flow.  As a result, when the morning breeze dies down between 1100 and 1300, PHX changes from East to West Flow almost daily.  East Flow has a negative impact on departures because all turbojet departures are required to converge over the uninhabitted Salt River Basin.  Using West Flow, North departures fly heading 260 and SoUth Departures heading 240.  Therefore West Flow allows more deparures with less visual separation and the Tower likes to change directon immediately after the morning departure push is over.  There are very few requests for opposite direction operations due to the gradient.  Density altitude plays no part in the decision as far as we're concerned.  If I had to guess I'ld say one per week.  While I'm sure the quote attributed to a P50 controller about the Tower controllers' eyes was accurate, it is not true.  (we know Tower controllers don't bother to look out the windows--just kidding)  Changing runway direction every day brings a lot of challenges and sometimes some harrowing moments.  Throw in a monsoon thunderstorm which includes wind shear and rapid wind direction change and look out. 

[JALTO]

Thanks for the replies....even the funny ones! My days in Phoenix (Tempe) are now over and I can head back to my land of humidity with a little more knowledge. 

Off topic but LHP50...since you mentioned the Salt River basin...If anyone out there has a chance to go tubing down the Salt River I highly recomend it

-Jalto