Negative /Positive Press?

[wb2uzr]

I listen to I guess what are called FBO frequencies, where the aircraft call in with fuel orders and miscellaneous requests as they approach their destinations. I often hear them ask for fuel with an amount, then either  negative or positive "press" (?) What is the significance of the "press" request? Just curious!

Thanks!

Scott

[wiedehopf]

would you mind linking an archived recording and note down a sample time so i can listen to it?

[wb2uzr]

Sorry, I should have been more clear. I hear this on my own scanner.

Thanks!

[AeroBill]

I think what is being referred to is regarding "positive or negative pressure refueling point." Look up "positive pressure refueling point" on Google
and you will get more information. Something to do with proper fuel flow in the gas tank and maintaining proper pressure, either positive or negative,
apparently during refueling.

[wb2uzr]

OK, that makes sense, I'll read up on it.

Thanks!

[ridejumpfly]

What you’re hearing is “prist” it’s a fuel additive to prevent icing but some aircraft don’t use it. The FBO needs to know if they want it or not.

Here’s a post with some more info.

http://www.askacfi.com/80/what-is-prist-and-why-is-it-used.htm

[wb2uzr]

Yep, that's exactly right. I just heard a flight call down, and it was clearly "prist" It didn't always sound like "press", but that's the closest I could come!

Thanks!