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I was flying with an A320-214 that had big winglets (I think they were called Sharklets). I noticed that the positioning lights were facing forward on the leading edge of the winglet (the "notch" in the picture).

Image of winglet light

I was wondering why the light is placed there, because it seems to be very unoptimal.

Isn't the light mostly blocked when viewed from behind? Why is not not placed at the top of the winglet? Is that even a big concern?

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2 Answers 2

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Position lights are only visible in certain sectors (see image). The red and green lights on the wings are not supposed to be visible from behind.

enter image description here

Image source: Learn to fly

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    $\begingroup$ Thanks for the image, that explains the placement. The other answer provides a bit more detailed reasons, hence why I accepted it. Cheers. $\endgroup$
    – Jens
    Jun 10, 2019 at 10:07
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There are three position lights. Red, Green and White. The red and green ones are placed on the wings and should be visible from the front and side up to an angle of ±110 degrees from the longitudinal axis. The white light is usually placed on the tail (or trailing edge of the wings) and should be visible from behind the aircraft, 70 degrees to either side.

Therefore: The red and green position lights on the wings should not even be seen from behind the aircraft, which is why they are positioned like that.

The reason this is done is because the angle on how you approach another aircraft defines who has right of way and who has to avoid the other aircraft.

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    $\begingroup$ Ah ok, that makes a lot of sense in combination with the right-of-way rules. $\endgroup$
    – Jens
    Jun 10, 2019 at 10:06
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    $\begingroup$ This is actually a throw back to nautical navigation. Boat/ship navigation lights are also positioned such that you can only see a red or green unless the other craft is coming almost directly at you. vessels have a white stern light that is required, and a mast light is optional. $\endgroup$
    – Rowan Hawkins
    Jun 1, 2020 at 14:54
  • $\begingroup$ @RowanHawkins: If you can only see the colourful lights from in front of the other vehicle, what's the point in having both red and green lights? Wouldn't having both red and green only be useful if they can be seen from behind the aircraft (allowing one to tell whether the other aircraft is approaching or receding based on whether the green light is to the left or the right of the red)? $\endgroup$
    – Vikki
    Mar 22, 2021 at 0:05
  • $\begingroup$ @Vikki-formerlySean Well simplified there are four options: directly towards you, left to right, right to left, away from you. Each of these can be identified as red+green, green, red, white. Saying: if you see green and red, you are most definitely in danger. $\endgroup$
    – rauberdaniel
    Mar 22, 2021 at 9:43
  • $\begingroup$ @Vikki-formerlySean You have many things to think about when navigating. It is much easier to remember 2 lights = possible problem than to try and remember which way around the two lights are for coming or going. Aircraft have one additional light that boats don't have. a red strobe on the bottom and a white one on top(boats call the top one a mast light). Those help you know if you are above or below the plane coming at you. Bogl's picture is not quite accurate in that the tail light beam is less wide. $\endgroup$
    – Rowan Hawkins
    Mar 29, 2021 at 21:00

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