In this clip, the pilot requests dimmed runway lights.

Tower, you able to reduce the runway lights, please?

[Tower dims runway lights]

Thank you much

This seems like a somewhat unusual request.

Why might a pilot request that? Is it because they were literally too bright? Or is there a different reason?

  • 11
    $\begingroup$ There are many airports where there is not a tower and the pilot can activate and control the intensity of the runway lights. This is done by the pilot clicking his/her microphone a certain number of times on the correct frequency to illuminate the runway lights to a desired intensity. $\endgroup$
    – user22445
    Commented Aug 8, 2023 at 14:05
  • 4
    $\begingroup$ Same reason that you don't want someone driving with their brights on at night, I imagine. :-) $\endgroup$
    – tuskiomi
    Commented Aug 9, 2023 at 19:47
  • 1
    $\begingroup$ Same reason I dim my dashboard lights when driving at night. (Unless, of course, I'm looking for paradise.) $\endgroup$
    – FreeMan
    Commented Aug 10, 2023 at 14:40

1 Answer 1


That is quite a normal request.

Runway lights can be extremely bright because they need to be visible through fog during daylight to provide lateral guidance during take-off and roll-out. See this related answer for some example images.

When the sky is very clear (low humidity / pollution) and it is night, the brightness of these lights at full power will blind the pilots.

Therefore, runway lights are dimmable. But sometimes, even at 5% of power, the lights can still be uncomfortably bright because the pilot's vision is fully adapted to a dark cockpit.

  • 7
    $\begingroup$ Especially so when flying with a HUD... if the Touchdown Zone lights are overwhelming the HUD symbology, it's nice to have a better choice than to raise the HUD brightness to dazzling high levels. For a foggy day, that's no concern, and it's good to have the runway lights blasting through the murk, but with a clear & moonless night... absolutely! $\endgroup$
    – Ralph J
    Commented Aug 8, 2023 at 14:20
  • $\begingroup$ @RalphJ Aren’t HUDs projected onto polarized glass? (Maybe even tinted-and-polarized glass?), I’d have thought that alone should ensure good contrast $\endgroup$
    – Dai
    Commented Aug 9, 2023 at 3:22
  • 4
    $\begingroup$ @Dai You can control the brightness of the symbology; the brightness of "the world" seen through the combiner isn't reduced (significantly) by the glass itself. That would be undesirable anyway, since sometimes you're scanning for rather dim lights (airport lighting, traffic, weather, whatever) and you don't want the HUD dimming those any further. And, in daylight, you're wearing sunglasses, so you wouldn't want the HUD dimming the view in front of you, more than the view everywhere else. $\endgroup$
    – Ralph J
    Commented Aug 9, 2023 at 4:02

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