Airplane A/C

[gargoyle999]

DW just came back from a buisness trip on Midwest Airlines from Mpls to Washington, DC and back with a stops in Milwaukee. She said the planes didn't have the A/C going until they were up in the air and everyone was roasting. No air at all was coming out of the overhead vent. Bet that was fun!

 

Glad the only flights I have booked are in Nov and next Feb. Probably won't have any heat though so I'll bring my parka and gloves on board.

 

I don't think it's a good idea to pack people into a small space and let them get all hot and sweaty before taking them up to 35,000 ft for a few hours. Guess next fee will be $20 for some cool air. :rolleyes:

[KLLund]

That's interesting .. because I take a sweater and socks .. some planes have Too much A/C

[Chan_T]

During my last flight, which happened to be on NW, the A/C was off until we were in the air. Many people asked about it and were told that the air would get going once we were in the air. Also, on our return trip (which was the last flight for them that night), the flight attendants asked everyone to let down their window shades before getting off the plane, so that the plane would not be so hot the following morning when they boarded.

[FlyerTalker]

A/C on the ground is supplied one of two ways. Either it is pumped in from the terminal in large "tubes" (ground air) or it is provided by the Auxiliary Power Unit (APU) in the back of the aircraft. The APU is a small engine that burns fuel to provide power to run the A/C and other systems. If you are at an airport that doesn't provide ground air, the alternative is the APU. And that costs money to keep it running.

 

There's actually a third method. It consists of opening the aircraft doors at MSP around 5am on a January morning.....:D

[gargoyle999]

There's actually a third method. It consists of opening the aircraft doors at MSP around 5am on a January morning.....:D

 

Oh yeah...that would cool everyone off fast! Can't wait to leave the free A/C come next Feb! :) Maybe they could "rent" those little hand held battery powered fans to people. Hmm...maybe I could start a business to sell them to the airlines, then the airlines could make money by charging a fee....win-win! :D

[Globaliser]

During my last flight, which happened to be on NW, the A/C was off until we were in the air. Many people asked about it and were told that the air would get going once we were in the air.

The auxiliary power unit that most modern aircraft have only supplies a limited amount of ventilation, and sometimes aircraft do get very hot until after takeoff. Also, sometimes the APU may be unserviceable for some reason, which removes even this potential source of ventilation.

 

Once the main engines are started, they will begin to supply ventilation. This is done by bleeding off some of the air from the highly-compressed air inside the compressor section of the engine, before the fuel is added to the mix. But the engines supply more air at high power, obviously, and they are seldom at high power when taxiing on the ground. So this remains a limited source of ventilation.

 

And then for takeoff and initial climb, the bleeds are often closed because they reduce the propulsion power produced by the engine, and at this critical phase of flight you want the engines to produce as much propulsion as possible.

 

So in many cases, you only get full "air conditioning" some minutes after takeoff. But then it can work pretty well.

 

Incidentally, air conditioning is a must for all aircraft. The bleed air taken from the engines is pretty hot - typically about 200 degrees centigrade. It has to be cooled before it can be supplied to the cabin. If it's warm inside at cruise altitude, it's only because the air hasn't been cooled quite as much as it could be.