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Question About Md80 Series

Wed Dec 26, 2001 12:19 pm

Flying as a kid on AA in the Md80 series, I saw these ducts underneath the planes as we were waiting to board the flight.

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Photo © Tom Canning

Now that I came across this picture years later I'm curious what the function of these seem to be? Do they relate to the air conditioning of the plane while on ground?? Any knowledge about it is appreciated. thanks

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RE: Question About Md80 Series

Wed Dec 26, 2001 12:52 pm

Well, I think you're right. It's cool air for the cabin while on the ground.

Another thing that makes me think this is that the DC-9 types have their AC packs in the REAR of the aircraft, kinda unique.
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RE: Question About Md80 Series

Wed Dec 26, 2001 11:40 pm

It is for air conditioning while on the ground. The MD80-s are know for having a poor air conditioning system while on the ground. The apu is unable to generate enough bleed air to run the packs to the full potential. You really notice it on a hot day when ground air isn't available. Also the MD-88's have another ground air connection on the left side of the fusealge about a 1/3 of the way back from the nose.
Fwd to MCO and Placard
Posts: 176
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RE: Question About Md80 Series

Wed Dec 26, 2001 11:44 pm

Super80: The yellow duct you see in the photo is for ground ventilation. Ground equipment can provide conditioned air when the engine(s) bleed air or APU is not available. This conditioned air can be cold or hot, depending on the capability of the ground equipment and the climatic conditions. The flexible yellow duct is attached to the ground air conditioning connector on the aircraft. Conditioned air is fed into the aircraft's air distribution system (in this case the left and right conditioned air ducts), then throughout the cabin. In this particular type of aircraft, the air conditioning/pressurization equipment is located in the aft accessory (tailcone) compartment, so the external hookup for the yellow duct is under the tail. In some other aircraft, the hookup may be under the belly, or in other locations. And of course, the conditioned air distribution ducts have check valves in them so when the engine(s) or APU air is available, that air does not flow backwards out the ground air conditioning connector. Regards,
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Thanks For The Responses N/t

Thu Dec 27, 2001 12:22 pm


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