I live in Portland,Oregon. I watched a large jetliner coming into the airspace heading to the airport. The red,green and tail lights were normal. But the headlights were blinking alternately. I have never seen that in all my years watching the sky. Is there a reason for the alternate blinking?Emergency onboard?


Some modern landing lights have a pulsating or alternating mode. It's just for being recognized more easily, has nothing to do with an emergency.

A constant white light heading right for you over a city full of lights doesn't get as much attention as a pulsating light which gets bigger each time as you get closer :)

Here is one example: https://www.preciseflight.com/pulselite-pulsing-aircraft-lights/

and their video:

  • $\begingroup$ Thanks. It just seemed unusual. $\endgroup$ Feb 29 '20 at 7:39

What you were likely seeing is the wingtip strobes which are white and flash alternatively. Aircraft don't have "headlights" per-say but they do have landing lights which do not flash by design but can be flashed manually.

  • $\begingroup$ The proposed duplicate suggests landing lights can flash. Or did I misinterpret that? $\endgroup$
    – PerlDuck
    Feb 28 '20 at 6:42
  • 1
    $\begingroup$ @PerlDuck landing lights can be flashed manually and its possibly thats what was seen but it is also possible it was the flashing strobes which flash by design. Ill edit my answer a bit to elaborate on the landing lights needing to be flashed manually. $\endgroup$
    – Dave
    Feb 28 '20 at 6:53
  • $\begingroup$ I edited my reply as well, I've seen many videos of aircraft that do have pulsating landing lights and no you don't have to manually flash them. $\endgroup$
    – Jan
    Mar 1 '20 at 8:19

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