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I was wondering. At different places I heard that civilian airplanes often (or even most of the time?) take off at less than 100% thrust.

For example a question that tackles this is here: Is it possible that derated thrust takeoffs are safer than normal takeoffs?

This makes a lot of sense to me.

However, whenever I see videos of fighter jets taking off (from normal runways, not from carriers), they always seem to use the afterburner. But surely they must have plenty of power to get to take-off speed without them, so doesn't this waste large amounts of fuel unneccessarily? What are the considerations for doing it?

Or is this just a "filter bubble" impression I got, because it just looks cooler and whenever those planes are filmed they know that they are and thus do it for the show?

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    $\begingroup$ Because they can? :-) $\endgroup$ – Pondlife Feb 25 '17 at 21:45
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    $\begingroup$ Or the filter bubble is the other way around: people mostly upload videos that look cool. $\endgroup$ – Jörg W Mittag Feb 25 '17 at 22:59
  • $\begingroup$ Filter bubble could also be that the planes are most filmed at air shows, where they perhaps use after burners for 'coolness'? $\endgroup$ – Tero Lahtinen Sep 16 at 12:13
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Military aircraft takeoff with afterburner when it is safer to do so with an exception- carrier pilots always light their cans while taking off (and also when the pilot wants to show off, but lets leave it at that).

The main consideration for using after burner in operational land based aircraft is the available runway length. When the aircraft is loaded heavily with ordnance, the runway required may be more depending on other factors (like OAT etc). In this case, it is better to go for afterburner takeoff. For example, Air Force Instruction 11- 2F- 16V3, F- 16 Operations Procedures specifically states:

3.6 Takeoff

3.6.6 Make an afterburner takeoff anytime the computed MIL power takeoff roll exceeds 50 percent of the available runway.

The same is true for other aircraft like the F-15 too:

3.7 Takeoff

3.7.2 ... For single ship takeoffs, if the single ship computed military power takeoff distance exceeds one-half of the available runway, takeoff using afterburner.

Another reason the pilots do it is to check the systems- it is better to check the afterburners on ground rather than finding any problems (like intermittent afterburner) in air. Of course in case of naval aircraft, the afterburners are on till the aircraft clears the ship.

Also, as @Jörg pointed out, people upload videos that look 'cool'- hence the impression that they always use afterburners rather than the boring military power takeoff.

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    $\begingroup$ Being a USAF veteran who was stationed at an active duty fighter base, I can confirm that they do take off with afterburners. I remember going on runs with my unit and having F-15s taking off near us - those things are loud. $\endgroup$ – user3305 Feb 26 '17 at 2:04
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    $\begingroup$ Tactical military aircraft hate the ground even more than other aircraft. I have even seen them shooting it and throwing things at it! So naturally they want to get away from it as quickly as possible. $\endgroup$ – A. I. Breveleri Feb 26 '17 at 2:39
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    $\begingroup$ I see. Good points. 50% of the runway is probably most often required. Is the required length calculated with or without AB? $\endgroup$ – Jens Feb 26 '17 at 6:53
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    $\begingroup$ @Jens from the either quote: "computed military power takeoff distance exceeds one-half of the available runway". $\endgroup$ – FreeMan Feb 27 '17 at 22:07

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