On both side of the lower fuselage of the AN-22 there are long bulges. While the undercarriage doors are visible, they only account for a small proportion of the length, making me doubt they're just fairings. There are also what look like air intakes though no obvious outlets on the photo below or other photos at Wikpiedia, but the video there might show something on the starboard bulge, forward of the undercarriage.

The cross section and (poorly-translated) text at globalsecurity.org don't say much, except to hint that they're outside the pressurised hull. A human-scale hatch/door just forward of the undercarriage doors suggests they're not fuel tanks.

So what are they?

An-22 in flight An-22 photo by user Toshi Aoki from Wikimedia Commons


1 Answer 1


This cutaway drawing shows it's the airconditioning unit, which would also explain why it has an air intake. enter image description here

Source - ww2aircraft.net

Zoomed version: ![![enter image description here

The relevant part of the legend:

![enter image description here

Next to the air conditioning unit, the sponsons also house other parts (as pointed out by @sophit in the comments):

  • 142: Port entry door
  • 141: port entry tunnel and inner pressure door
  • 140: Triple twin-wheel main undercarriage bogies
  • 135: Sponson mounted cargo winch, port & starboard
  • 138: Hydraulic retraction jacks
  • 136: Inward opening mainwheel bay doors
  • 112: Spons bag-type fuel tanks
  • 111: Avionics racks, port and starboard
  • 110: Fuselage sponson tail fairing
  • 1
    $\begingroup$ A rare immediate acceptance from me - normally I leave it 24 hours but I didn't see much point. I'm surprised that you found anything useful on pinterest $\endgroup$
    – Chris H
    Feb 13 at 9:56
  • 1
    $\begingroup$ I think I need to review the answer, this a AN-12, not an AN-22. But I think the answer will be same. Let me see if I can find an AN-22 cutaway $\endgroup$
    – ROIMaison
    Feb 13 at 10:10
  • $\begingroup$ Strange, I get pinterest hits but they're not relevant (even with quotes) for the same search. Maybe Google knows I get frustrated with pinterest on the rare occasions I click link to it and suppresses the results $\endgroup$
    – Chris H
    Feb 13 at 10:14
  • 1
    $\begingroup$ @ChrisH, you'll be happy to learn I found the correct AN-22 cutaway drawing outside of Pinterest :) $\endgroup$
    – ROIMaison
    Feb 13 at 10:15
  • 1
    $\begingroup$ Note that there's something more than the air-conditioning: the entry door and tunnel (141 and 142), some fuel tank (112) and some avionics (111)! This is a really nice example of the efficient use of space which is of paramount importance in the aerospace world $\endgroup$
    – sophit
    Feb 13 at 10:19

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .