This question asks about the S-duct of the L-1011 Tristar. Fooot's answer shows a cut-out of the L-1011. Looking at this cut-out, I'm wondering:

If the engine is at the 'normal' location of the APU, where did the designers of the L-1011 put the APU?

I did a search, and found this site which mentions

The APU is located in a compartment in the aft fuselage.

Another site mentions

Its still in the "tail". Its mounted below the #2 engine. Just forward of the tail skid.

But I don't see how you could fit the APU in the small available space.


2 Answers 2


enter image description here
(Source via aircraft.wikia.com)

APU is number 134 on the cutaway, which you can find near root of left stabilator leading edge. It is ahead of the engine, below the intake duct, on the left side.

enter image description here
By Reedy (Own work) [CC BY-SA 3.0], via Wikimedia Commons

Its exhaust is on the right side close to the stabilator's leading edge.


The APU on the B727 was placed inside the main gear wheel well.

enter image description here

image source

It drew air from inside the wheel well, so it was only for use on the ground. The exhaust was on the top of the right wing close to the fuselage.

enter image description here

image source

  • 5
    $\begingroup$ And man is it loud. SOURCE: worked on them for 20 years. $\endgroup$ Commented Nov 5, 2018 at 20:16
  • 4
    $\begingroup$ @SportsRacer Yes they were. Used to work at the FedEx hub back when the fleet was mostly 727's. The head cans we wore were not enough working at the belly cargo doors. $\endgroup$
    – TomMcW
    Commented Nov 6, 2018 at 18:53
  • 1
    $\begingroup$ Does this mean the APU in the 727 couldn't be used to provide emergency power in air? $\endgroup$
    – zymhan
    Commented May 16, 2019 at 20:37
  • 1
    $\begingroup$ @TomMcW: Did they not have ground power in Memphis? $\endgroup$
    – Vikki
    Commented Nov 11, 2019 at 2:31
  • 2
    $\begingroup$ @zymhan Just saw your question. The APU on a 727 cannot be operated in flight. Ground use only. $\endgroup$ Commented Jan 11, 2020 at 18:54

You must log in to answer this question.

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