Since Helios 522 was unpressurized all the time, shouldn't the faster-than-usual change of interior air pressure during the ascent have alarmed the pilots that something isn't alright because their ears would feel a more rapid change of pressure, possibly hurting because of the faster change? Within 15,000 ft the TUC is unlimited so they should have become suspicious that their ears hurt that much and be able to do something about it if they realized the danger, shouldn't they?

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    $\begingroup$ Airliners don't climb fast enough to cause a dramatic change in pressure that would be immediately noticeable. And besides, ears don't "hurt" going up... $\endgroup$ Nov 6, 2022 at 21:26
  • $\begingroup$ @MichaelHall Now that you say it, indeed I remember that when my ears hurt it was during a plane's descent rather than ascent. Unless perhaps when I was sick, but it's a long time, I don't recall well. So ears only hurt when the exterior pressure gets higher than the one within the Eustachian tube? $\endgroup$
    – Giovanni
    Nov 7, 2022 at 9:58

1 Answer 1


As a general rule, without going into specifics of this particular case, no.

One does not necessarily notice, or rather pay attention to pressure changes if you fly a lot, which is the case of professional pilots. Equalizing the pressure inside the ears becomes pretty much a reflex that goes unnoticed.

In the case of passenger planes (and military jets even more so) the rate of ascent is relatively high, which sneaks the lack of oxygen into the equation. One does not need to climb very long for the effect of thinning air to accumulate, numbing the senses and compromising the judgement.

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    $\begingroup$ I thought it is because they fly a lot that they would notice a more rapid change than usual. $\endgroup$
    – Giovanni
    Nov 6, 2022 at 10:54
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    $\begingroup$ @Giovanni If the outflow valve wasn't fully open, it might moderate the (cabin) rate of climb somewhat, enough to make the higher rate less obvious. Years ago, I had an unpressurized maintenance ferry flight, although with both packs working (as they were on the Helios flight). At 10,000', the cabin wasn't all the way there, and I had to hold the outflow valve control to OPEN much longer than I'd normally do (this was when we did cycle it manually during preflight checks) to get a 10,000' cabin. So it may have been less than fully open, enough to shallow but not stop the cabin's rate of climb. $\endgroup$
    – Ralph J
    Nov 6, 2022 at 21:29

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