The engines for the 767 weight about four tons each. That seems like a lot of weight for a lightweight aluminum airframe to carry in addition to passengers and other cargo. How is that possible, for a lightweight aluminum airframe to carry that much weight?

  • $\begingroup$ Metals (and fiber materials even more) are quite strong. Just think for example about a bike frame: it weights just a couple of kilos but can carry a hundred kg plus road roughness without any problem. Airframes are no exception to this rule. $\endgroup$
    – sophit
    Dec 28, 2023 at 23:23
  • 7
    $\begingroup$ Forget about the engines. The 767-400 can carry up to 100 tons of fuel, most of which is actually stored in the wings. The weight of the engine is small in comparison. $\endgroup$
    – Daniel K
    Dec 29, 2023 at 1:48
  • 2
    $\begingroup$ Forget the engines' weight. They are also producing over 20 tons of thrust each. $\endgroup$
    – Therac
    Dec 29, 2023 at 15:42

1 Answer 1


Aluminum is stronger than you might think, especially when it is configured in such a way to be more rigid.

How is that possible, for a lightweight aluminum airframe to carry that much weight?

Considering how much aluminum can handle weight-wise, 8 tons isn't that much for a 95 ton aircraft. Also, just because an airframe is light weight doesn't mean it's weak or can't handle a lot of stress. If you look at a bare 767 frame, you'll see how many aluminum ribs and reinforcements there actually are. (I was trying to find a good picture, but I didn't see any)

Also, the engines aren't really being held by the actual airframe. They're being held by mainly the wing spars and the wing box. To put it simply, the wing box and wing spars are separate from the aluminum airframe. The wing box and wing spars are actually supporting the whole aluminum airframe in flight.

  • $\begingroup$ Wing belongs to the airframe by definition, the engine(s) is attached to the airframe. $\endgroup$
    – sophit
    Dec 28, 2023 at 23:16
  • $\begingroup$ @sophit well yeah it is in some way attached to the airframe, through a set of linkages though. $\endgroup$
    – Wyatt
    Dec 28, 2023 at 23:32
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    $\begingroup$ @sophit I think that what Wyatt meant to say was that the wing supports the whole fuselage in flight. $\endgroup$
    – MikeB
    Dec 29, 2023 at 15:36
  • $\begingroup$ @MikeB yes that’s correct $\endgroup$
    – Wyatt
    Dec 29, 2023 at 16:32

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