MD-90 Aircraft: The Definitive Thread
Sep 26, 2007, 3:22 am
#46
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More than likely the "tube" is the air conditioning coming into the plane from the gate A/C unit. No eshaust is coming out anywhere near row 13 on any aircraft except on a (C/E)RJ. You were likely sitting near the chase that takes the a/c from under the cabin to the overhead vent system.
Sep 26, 2007, 5:17 am
#47
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Exhaust? LOL Oh this is toooo funny. Sorry to laugh at your post. You'll just have to start paying a little more attention at the airport.
It's definately the air conditioning hose and almost every airplane gets hooked up to one while at the jetway. If you look at yhr unused jetways while you taxi by you'll see the yellow hoses stored in a large basket beneath them.
The reason it's taken off before the engines get started is so it doesn't get sucked in them. About 15 years ago I saw one get sucked into a 757 engine. It looked like Big Bird blew up with all the tiny shreads of yellow plastic around the ramp.
It's definately the air conditioning hose and almost every airplane gets hooked up to one while at the jetway. If you look at yhr unused jetways while you taxi by you'll see the yellow hoses stored in a large basket beneath them.
The reason it's taken off before the engines get started is so it doesn't get sucked in them. About 15 years ago I saw one get sucked into a 757 engine. It looked like Big Bird blew up with all the tiny shreads of yellow plastic around the ramp.
Last edited by BFG; Sep 26, 2007 at 5:25 am
Sep 26, 2007, 7:21 am
#51
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As others have mentioned, typically installed at the gate for HVAC of the aircraft. In some airports, BWI for instance, these are only connected to airframes whose APU is not sufficiently sized to run the internal HVAC. In others, they are connected to all aircraft, in order to permit the use of less fuel as the APU would only be used for internal power requirements if no shorepower is provided.
Sep 26, 2007, 7:48 am
#52
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May have also been ground-air for starting the APU or engines, though I would think it would connect further back on the fuselage if this were the case.
Last edited by IsleOfMan; Sep 26, 2007 at 8:38 am
Sep 26, 2007, 8:36 am
#53
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Did you submit your comments to SeatGuru? I'd suspect that getting them to update the seatmap will be a lot easier than getting Delta to install a window at that seat.
Sep 26, 2007, 8:40 am
#54
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I'm not sure where the air start hoses get hooked up on the MD90 but those hoses are brown and have a much smaller diameter than the A/C hoses. As the OP stated these were large yellow hoses.
Sep 26, 2007, 11:28 am
#56
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Geez, the DL forum is certainly a friendly place...
The thought occurred to me that whatever was in the tube was indeed going into the aircraft, but as I'd never seen anything like it before and couldn't think of a reason why any air would need to be blown into the plane (since, at least as far as I knew, the AC was powered by the APU--guess my airports never do this...), I assumed it was some sort of exhaust.
Plus, the wall next to me was hot to the touch...
(Sorry for not "paying a little more attention"--seeing as how there was no window, it was sort of hard to see exactly what it was.)
The thought occurred to me that whatever was in the tube was indeed going into the aircraft, but as I'd never seen anything like it before and couldn't think of a reason why any air would need to be blown into the plane (since, at least as far as I knew, the AC was powered by the APU--guess my airports never do this...), I assumed it was some sort of exhaust.
Plus, the wall next to me was hot to the touch...
(Sorry for not "paying a little more attention"--seeing as how there was no window, it was sort of hard to see exactly what it was.)
Sep 26, 2007, 12:17 pm
#58
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The air coming likely was hot... it is used in place of bleed air from the engines to turn the compressors for the air cycle machine (ACM) which, in turn, conditions a combination of cool (relatively) ambient air and hot bleed air (or in this case, the hot ground-air).
Sep 26, 2007, 1:36 pm
#59
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The air would not have been hot, the yellow large diameter hoses are for cold (already conditioned) air that goes right into the air conditioning distribution ducts (after the air cycle machines). As mentioned earlier external high pressure air used for engine start or running the air cycle machines for heating/air conditioning is a much stronger and smaller diameter hose. The side of the plane was probably warm from the sun heating the metal.
Sep 26, 2007, 1:57 pm
#60
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Thanks, alanh, for pointing that out. 
Next time I get to an airport in a warm part of the country, I'll keep my eyes out for other a/c hooked up to ground-based a/c (haha...sorry).
I've flown plenty in warm climates--I make semi-regular trips down to LAX and have gone several warm places in the last year or two--but have never noticed this. AS and UA are my carriers of choice, so I usually end up on 737s and A320s and haven't noticed rows on these aircraft missing windows or even the sound (it literally sounded like the jet engine was right outside of my "window"). Maybe the mechanism and hookup location are different on the Boeing and Airbus equipment...?
Next time I get to an airport in a warm part of the country, I'll keep my eyes out for other a/c hooked up to ground-based a/c (haha...sorry).
I've flown plenty in warm climates--I make semi-regular trips down to LAX and have gone several warm places in the last year or two--but have never noticed this. AS and UA are my carriers of choice, so I usually end up on 737s and A320s and haven't noticed rows on these aircraft missing windows or even the sound (it literally sounded like the jet engine was right outside of my "window"). Maybe the mechanism and hookup location are different on the Boeing and Airbus equipment...?