Having just been to a bunch of air museums, I've seen quite a few of these:

enter image description here

img credit http://www.thewire.com/global/2013/02/iran-new-stealth-fighter-jet-fake/61781/

Those red pads they put in the jet engines that say "remove before flight" - what happens if I try to start the engine with that pad in there? Would the exhaust just blow it out?

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    $\begingroup$ If anyone can find a better, clearer picture of these pads I'd much appreciate it. Part of it is likely that I don't know what their real name is. $\endgroup$
    – Undo
    Sep 1, 2014 at 13:53
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    $\begingroup$ Is that a real aircraft? $\endgroup$ Sep 1, 2014 at 13:53
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    $\begingroup$ I don't believe it is, given thewire.com/global/2013/02/iran-new-stealth-fighter-jet-fake/…. But it does show the thing I want to show. Again, if you can find a better image, please do! $\endgroup$
    – Undo
    Sep 1, 2014 at 13:55
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    $\begingroup$ Ah ok, I thought it looked a little fake ;-) $\endgroup$ Sep 1, 2014 at 13:56
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    $\begingroup$ in that case it's a cover over the jet exhaust, either it will stop the engine from spooling up enough to ignite or blow off during spin-up. $\endgroup$ Sep 1, 2014 at 13:57

1 Answer 1


As Ratchet Freak says, it's going to blow away or cause the engine to fail. Latter might happen if it sits tight enough that it doesn't get blown away before overpressure develops in the engine.
Not a good thing, damage may happen.

My guess most likely outcome is that it will be blown back, possibly colliding with parts of the aircraft (and thus causing damage) or hitting the hangar wall or whatever else is behind the aircraft with some speed (unless there's a lot of clear area, in which case it'd flutter to the ground), if it's not overfastened.

And to be complete, it's a cover to prevent things from getting into the engine while the aircraft is parked. Dust, animals, anything.
There will be others on the air intakes as well.

  • $\begingroup$ that would depend on how much pressure it can take before popping off and how heavy the pad is. $\endgroup$ Sep 1, 2014 at 16:02
  • $\begingroup$ Mrs Squirrel says to Mr. Squirrel, see the nice house I found. Baby Squirrel says what's that smell.... $\endgroup$
    – CGCampbell
    Sep 2, 2014 at 16:22

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