Engine meme...or something

I recently found this (IMO funny) picture. All funny and all. But let's make this a real situation.

Let's suppose I see my crush and his BF doing this, and I come with this 'genius' idea (alright, it's anything but a genius idea, but still) to start the engine they are sitting on. And no, I am not nice enough to turn the beacon lights on.

How likely is it that the engine gains enough suction to suck them in without they noticing it in time (considering the fact they need to standup and run for their lives)?

How long does it take for the engine to spool up enough suck a person in?

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    $\begingroup$ I'm not sure why the VtC for "opinion based". Seems that there are some pretty reliable facts already posted in the answers. $\endgroup$
    – FreeMan
    Commented Mar 27, 2019 at 17:47
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    $\begingroup$ Since they are both wearing ties, one would hope that'd get sucked into the core. $\endgroup$
    – MikeY
    Commented Mar 27, 2019 at 20:28
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    $\begingroup$ Ironically, that looks like an A320, but the start panel is from a B737. $\endgroup$
    – Bianfable
    Commented Mar 28, 2019 at 8:36
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    $\begingroup$ That picture's totally inappropriate for this site. Who starts engine 1 first!? $\endgroup$
    – 0xdd
    Commented Mar 28, 2019 at 14:56
  • $\begingroup$ Not trying to misgender anyone here, but, considering that the people in the picture appear to most likely be a guy and a girl, it'd probably be "...and his GF" or "and her BF". ;-P $\endgroup$
    – Vikki
    Commented Feb 5, 2023 at 15:23

3 Answers 3


A start on a TF all the way to idle is about 20-40 seconds depending on the engine, and the fan itself won't do more than creep a bit until the core actually lights off which is 5-10 seconds, so they'll have lots of time to get down and get away as per @ymb1's diagram, once the wheeEEEEEEEEEEtickticktickticktickticktick starts.

  • 24
    $\begingroup$ I love the written description of the startup sound. +1 $\endgroup$
    – Pugz
    Commented Mar 27, 2019 at 18:56
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    $\begingroup$ From now on this is the sound of evil. $\endgroup$
    – Peter
    Commented Mar 27, 2019 at 19:38
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    $\begingroup$ @Peter It's music. Best of all is the sound of a Huey helicopter. youtube.com/watch?v=IA9knzev85I Listen carefully. There must be 4 or 5 ascending howls and groans and whines in a sequence as the, starter, engine and various gearboxes wind up in turn. It's a symphony. $\endgroup$
    – John K
    Commented Mar 27, 2019 at 22:09
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    $\begingroup$ Hmm... How much suction is the core creating during that 20-40 seconds, though? N2 has to get relatively high before the core lights, doesn't it? Seems like that would still result in a pretty substantial mass flow (though obviously not as much as when the fan spins up.) $\endgroup$
    – reirab
    Commented Mar 28, 2019 at 16:07

enter image description here

The suck zone ahead of a CFM56 on an A320 is less than 5 meters. The couple have enough time to take a leisurely walk toward the cockpit window.

The engine start time takes upwards of a minute (the starter is limited to four 2-minute bursts, followed by a 15 min cool down). Newer engines take longer to start.

On the neo with PW1000G engines it's 2.9 m. On the A380 it's, surprisingly, only 4.5 m.

How soon can they reunite after a shutdown? It won't be a long wait.

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    $\begingroup$ And, it gets really loud immediately when the starter engages. That'll get your attention right away, followed by the fan starting to turn slowly. $\endgroup$
    – Ralph J
    Commented Mar 27, 2019 at 17:05
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    $\begingroup$ The suction power is massively overrated. If you had hard vacuum in a cylindre, you only need to go 1 diameter away to have negligible suction. But it ramps up nicely inwards from there. $\endgroup$
    – Stian
    Commented Mar 28, 2019 at 22:29


I said, let's get away from this loud engine!

Before it can even start to turn the fan, the noises the engine must make will be so deafening as to force the people in that location to flee.

And even before that, there would be clunks, shakes, and vibration that would be very noticeable, and put even deaf people on notice to clear out.

There would be no mistaking the engine starting up. They would have at least 10-15 seconds to clear out.

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    $\begingroup$ This doesn't actually answer the question. Q: "How long?" A: "Well they'll definitely hear it!" $\endgroup$
    – Clonkex
    Commented Mar 29, 2019 at 2:09
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    $\begingroup$ @Clonkex it's implicit that it gets noisy enough, early enough that they would move away because of the noise before they would get sucked in. $\endgroup$
    – Baldrickk
    Commented Mar 29, 2019 at 13:12
  • $\begingroup$ Obviously each engine takes a different amount of time to start. The point is that you would always notice it starting up. $\endgroup$
    – zymhan
    Commented Mar 29, 2019 at 14:09
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    $\begingroup$ @Baldrickk Yeah I know, but generally it's expected that Stack Exchange questions should directly answer the question. I'm just suggesting perhaps the author should edit the answer to make it a more direct answer. And of course... I have a cunning plan... $\endgroup$
    – Clonkex
    Commented Mar 30, 2019 at 23:01
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    $\begingroup$ @Clonkex ok, there ya go! It's a hard question to answer so I had to couch it... $\endgroup$ Commented Mar 31, 2019 at 5:09

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