This has been bothering me for some time and I am finally going to ask the question?My wife and I use our hot tub regularly (yes we/I am lucky), and during clear nights we always enjoy looking skyward and ID'ing the constellations and watching satelites whiz overhead. We are also on a flight path (Duncan, BC) for aircraft making approaches to Vancouver and Victoria airports, albeit, still higher elevation. We have noticed sometimes that occasionally we see what appears to be aircraft that temporarily turn on their landing lights (very bright) for a short couple of seconds and then turn them out.Can someone who is a pilot please explain what this might be, or what is happening on the flight that requires this action?We have often wondered if was a signal to show a visual location of aircraft for VFR flying or something.

Like bus drivers tooting their horns, just saying hello to another comapny aircraft in the area?Cheers.- jahman.

Well I will be darned. As my kids say kwel.

When ATC warns me of traffic in the area during cruise, I'll flick my landing/taxi lights on. In the 172 and 182 the passenger courtesy lights (bottom of the wing used for loading/unloading) also come on if there's difficulty spotting the traffic.

Yes they are very bright and often appear to be underneath, so that explains it some more.

Many airlines require in the descent to turn on recognition lights and landing lights as they come down through 10,000' until they are not needed after landing. Where you live is an area where we descend down through 10,000' to go into Bellingham and Vancouver. What appears of the lights going off is usually caused by the lights being recessed into a housing and when the angle is just right they appear to turn off but they are still on.Here is an example of the housing on a Boeing 737 Other landing lights may pivot into the bottom of the wings and fuselage for aerodynamics and to protect from damage. When you turn them on they can take a little while to get into their forward pointing position so that can also make it look like it is pointing downwards. Other lights you may see illuminated are the ice lights that shine down the leading edge of the wing so the crew can see ice accumulations at night. They are located just in front of the wing on the fuselage. I noticed a lot more aircraft using these lights to help in quick acquisition of traffic

Well thanks for this detail, there is a lot more to it than I had imagined.