A couple of months ago (I’ve been meaning to, and not remembering to, post this question for that long), I was driving home from work, and saw an airplane doing something odd (meaning “something I’d never seen one doing before”).
It appeared to be your run-of-the-mill 757 or suchlike commercial aircraft, at a medium altitude (it wasn’t huge, but it wasn’t a dot), flying in a straight line (as far as I could tell), and it appeared that the “headlights” on the wings (for lack of a better term) were flashing.
They’d get bright, and then fade out, at a rate of about once per second. On… Off… On… Off…
I saw the plane from nearly head-on, so I could tell it was the lights (on both sides) doing this, and not a reflection of the late-afternoon sun (one wing would have been in shadow). This flashing-lights business kept up for as long as I could keep the plane in sight and drive safely, which was about 30 seconds.
Was this the aircraft version of “flash to pass?” Was it a standard thing to do in some situation? Or was one of the flight crew just screwing around?
Dr. Lao, if the big, bright, white lights along the front of the wings, near the body, of a large commercial airliner are the “landing lights” (which were the things that were flashing regularly) then…
…ChalkPit, the closest this came to any series was to number 4, except it wasn’t at night, the aircraft in question was probably more than 2,000 feet up, and this aircraft was a few miles away from, and moving away from, Dulles International Airport, with no smaller airfields whatsoever underneath. Also, there appeared to be no other aircraft anywhere close to the one I saw. Just lots of clear blue sky.
And it’s hard to believe that what looked like a big passenger plane would be the intercepting plane, but I looked at that column of signals too, and found nothing close, anyway.
Just a WAG, but landing lights are very directional, so if the landing lights appeared to be flashing, could it be that the plane was encountering some turbulence, and bobbing up and down slightly? To an observer at a fixed position, this could make it appear that the lights were flashing. A car approaching you on a road with a lot of dips in it can appear to be flashing its high beams at you, for the same reason.
Or maybe the pilot was trying to warn you about a radar trap ahead!
I’ve been a passenger on a plane which did the blinking landing lights thing, and in that case I’m sure it was to increase the visibility of the plane in crowded airspace.
Seems like Gelaan’s cite provides the answer. The only odd thing left is that I like watching planes fly about, and have missed this flashing-lights thing for four-plus years. Unless Southwest’s plans went down the tubes, and I coincidentally saw one of the three originally-outfitted planes last month.
Thanks, folks, for the jokes. I needed a smile today.
Flashy lights are used on airplanes to increase visibility (and is probably the most likely explanation). There is some variability in these systems.
There’s the “bobbing up and down in turbulence” theory.
The lighting system could be having a malfunction of some sort.
Occassionally, air traffic might ask you to blink your lights. For instance, if you’re having radio problems where you can’t transmit, they might say something like “if you can hear us flash your lights”. If you flash your lights they’ll keep talking to you. If you don’t, they’ll get out the light gun and switch to visual signals.
It cycled quite regularly. And I could see the lights well enough even at an angle to tell they were going bright-dim-bright-dim, so the landing lights don’t have that tight a beam.
Always possible, but what a bizarre malfunction!
This plane was facing almost 180 degrees away from the nearest tower. The next-closest tower that I’m aware of in the direction it was headed was at least 100 miles away (there are probably smaller airfields in between, but I doubt they’d be talking to a big airliner).
Yes, but it was close to Dulles, and given that National’s not too far away, the whole area is probably considered densely trafficked. Had I known about the move to make flashing landing lights a standard, I wouldn’t have even asked. But I will keep my eyes open to see how many other planes I can spot doing it.
I fly private planes in the Dallas area and have seen the flashing lights here too. I’ve wondered what they were for. I suspect that visibility in dense traffic areas is the best explanation.