Trim air off while at the ramp

[threexgreen 3,139]

I fly for United Virtual and always turn trim air off while at the ramp because it's what United pilots do in real world. I have however no idea why anyone would do so since it's a bit weird to manage the temps in the cabin. You have to look after CONT, FWD and AFT cabin and adjust the respective settings because, well, trim air is off and it doesn't balance the temps itself.

 

Anyone know more?

[JRBarrett 3,070]

IF the aircraft is being cooled/heated on the ramp by the packs, using APU bleed air, not sure why the UAL pilots would turn off the trim air - the ECS system would not work properly with it off.

 

On the other hand, if the aircraft is hooked up to ground conditioned air, turning the trim air off (or on) would make no difference, as the packs are not used with external conditioned air.

[Spin737 102]

I fly for United Virtual and always turn trim air off while at the ramp because it's what United pilots do in real world. I have however no idea why anyone would do so since it's a bit weird to manage the temps in the cabin. You have to look after CONT, FWD and AFT cabin and adjust the respective settings because, well, trim air is off and it doesn't balance the temps itself.

 

Anyone know more?

What makes you think the Trim Air is off?

[Stearmandriver 2,292]

We couldn't possibly be talking about one or both recirc fan switches, could we? There's times when that makes sense. I don't know UAL procedures so just guessing... I'd be interested also, in knowing why they'd turn the trim air off.

[threexgreen 3,139]

 

 

What makes you think the Trim Air is off?

 

I remember reading a post on here from someone who said he had been talking to a UAL pilot about it. I was curios after reading that so I took a look at some cockpit shots of UAL 737s and every shot I could see the trim air switch it was indeed in the off position.

 

 

 

We couldn't possibly be talking about one or both recirc fan switches, could we? There's times when that makes sense. I don't know UAL procedures so just guessing... I'd be interested also, in knowing why they'd turn the trim air off.

 

It's the trim air I'm curious about.

 

It's a completely different angle obviously than when I'm 'sitting' in the NGX cockpit but to me the trim air switches look to be more in the OFF position than ON:

 

http://www.airliners.net/photo/United-Airlines-%28Continental-Airlines%29/Boeing-737-824/1942779/L?qsp=eJwtjc0KwjAMx19l5OxFBg520xfQgy8Q0qBhtS1pxJWxdzcWbz/%2BnxtQTsar3VthmKEyKj3hAAUVXxXmDRZun6zBGd5JjMOAolES12Eap4EyLUXMKzWrXZrHAhqfibh4%2BK9fNbD%2BLK7U1x/%2BdnRgvXWG8eR6kFoi9g02lAj7/gXJVjZp

 

http://www.airliners.net/photo/United-Airlines/Boeing-737-824/2337923/L?qsp=eJwtjc0KwjAMx19l5OxFBg520xfQgy8Q0qBhtS1pxJWxdzcWbz/%2BnxtQTsar3VthmKEyKj3hAAUVXxXmDRZun6zBGd5JjMOAolES12Eap4EyLUXMKzWrXZrHAhqfibh4%2BK9fNbD%2BLK7U1x/%2BdnRgvXWG8eR6kFoi9g02lAj7/gXJVjZp

[Ralgh 43]

I have some friends who fly the 737 for them. They were having problems with ZONE TEMP lights coming on during the power transfer after engine start so they waited until after and then turned the trim air on. I have almost 14 years on the 737 at American and never saw that problem. I'm not sure they actually use that procedure any more. Or maybe they stopped doing it and started again. I'll have to ask one of em.

[Ralgh 43]

I just got my buddy to confirm it. They don't touch the trim air any more.

[Spin737 102]

They were having problems with ZONE TEMP lights coming on during the power transfer after engine start so they waited until after and then turned the trim air on. I have almost 14 years on the 737 at American and never saw that problem.

 

Yeah, drop out of LNAV, sure. ZONE TEMP lights? Never. Weird.

[threexgreen 3,139]

 

 

They were having problems with ZONE TEMP lights coming on during the power transfer after engine start so they waited until after and then turned the trim air on.

 

Do you know anything as to why the lights were coming on? The exact same thing happened to me in the sim a while back and I thought I had done something wrong.

[Ralgh 43]

Nobody ever told me if they knew why the lights were coming on, just when. I have friends who fly the 737 for a few airlines so when we talk we tend to compare notes. So far Continental is the only airline I have heard of having this problem.