Which part of the aircraft contributes the highest portion of weight?

Note: we had argument that, wires connecting the avionics systems are the major contributors of aircraft weight. Due to some issues with optical fibre technology this is not been used in aviation yet. So my question arises as mentioned above.

  • 2
    $\begingroup$ A380-800: Total wire count: ~100 000, Total wire length: 470 km, Total weight of wires: 5,700 kg. $\endgroup$
    – mins
    Nov 4, 2015 at 10:33
  • $\begingroup$ @mins 5,700 kg is huge weight for the aircraft, I'm sure there are many technologies are popping up in the field to make it wire free? $\endgroup$
    – Lucky
    Nov 4, 2015 at 11:15
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    $\begingroup$ @mins, I think this also includes all the electrical wiring (i.e. to provide power to lighting etc.). They say that 30% of this wiring is a candidate for wireless, so I think 30% of these cables is used to transfer data (and relevant for an optical fibre discussion) $\endgroup$
    – ROIMaison
    Nov 4, 2015 at 11:16
  • $\begingroup$ @lucky, 5700 kg is only 1% of the max takeoff weight of the A380. $\endgroup$
    – casey
    Nov 4, 2015 at 16:43
  • 1
    $\begingroup$ Fuel: It weight from ~20% for short-haul medium airliners (b737NG) to ~38% for long-haul jumbo(A380) in terms of Maximum takeoff weight $\endgroup$
    – Him
    Nov 6, 2015 at 11:49

2 Answers 2


Aerospace Engineering e-Mega Reference shows the following table for two aircraft (the large commercial jet, the B747-100, and the military jet, the C-5A). You can see that it differs quite a lot between the B747 and the C-5 already, so it's hard to give a definitive answer for all aircraft in general.

Also, it depends a lot on how you break down the components, for example, here the Nacelle and Propulsion system are shown separately, but if you combine the two (and some others as is done in the dry engine weight, I think) things could change. The Aerospace Engineering e-Mega Reference points to Beltramo as the source for the numbers. Perhaps you could find some information there about what belongs to which group.

However for both aircraft, it can be seen that the Wing and the Airframe are significant contributors (and for the B747 furnishing is also a large part of the weight)

I think they included all the wiring in the Avionics part (that would make sense to me), but still it is a relatively small part of the total weight.

Weight breakdown

  • $\begingroup$ I wonder what the distinction between "propulsion system" and "dry engine weight" is ... $\endgroup$ Nov 4, 2015 at 9:16
  • $\begingroup$ That's always the difficulty with these tables. I think the dry engine weight would also include the nacelle weight (and perhaps the pylon weight?). $\endgroup$
    – ROIMaison
    Nov 4, 2015 at 9:32
  • $\begingroup$ @HenningMakholm: The propulsion system includes all stuff like the engine quadrant in the cockpit, the propellers (if any are fitted) and (now the definition becomes softer) everything forward of the firewall / all engine mounts, cooling and lubrication liquids. The dry engine is just the engine as it comes from the manufacturer, not even with oil inside. $\endgroup$ Nov 4, 2015 at 9:42
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    $\begingroup$ I checked the original source (link in my answer) and it states: "The propulsion system includes the engines (which are not considered in this study), the fan exhaust thrust reverser system, the engine exhaust thrust reverser/spoiler system, the engine system and fuel system. The fan exhaust thrust reverser system includes the translating structure, cascades, blocker doors, fan exhaust ducting located with the translating structure, and the actuation system and controls. ... $\endgroup$
    – ROIMaison
    Nov 4, 2015 at 10:28
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    $\begingroup$ So in short, the propulsion system is everything related to the engine but the engine itself and the nacelle. $\endgroup$
    – ROIMaison
    Nov 4, 2015 at 10:31

If you mean by part of aircraft it will be the landing gear.

But if you mean what other stuff add weight you have the electronic entertainment system that adds alot of wires and cables which add weight to the airplane but with no operational use for the airline its only to entertain passengers.


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