Pulsing landing lights?

[Seloco]

Observed from West London, UK around 17:25z on Sunday 25th January:

An aircraft appears low from the south east, from approx. direction of LGW, flying north west and climbing, eventually turning north and continuing overhead London. Unknown type, but from speed and lights arrangement could be narrowbody commercial (but not Airbus, as no double flashing strobes).

All the time though, its landing lights (at least two, could be more) are pulsing, at approximately 1 cycle per second, from full on to practically off and back again.

I've never observed this before. Anyone any ideas as to what/why?

[GrantT]

What were the conditions like? It could have been an optical illusion.

[PAXboy]

This question was asked only a few months ago in PPPRuNe.

This was first implemented some years ago and the number of a/c with this option is increasing. I cannot say which particular a/c have it but it is probably on new and available as a retro fit during an overhaul. (Someone will be along in a minute to tell us!) The lights appear to go "from full on to practically off" as the flash unit applies power again before the filament has fully extinguished.

As you discovered, it draws the eye more rapidly than steady lights. You will find that the lights stop flashing shortly before touch down.

[604guy]

Pulselight(R) system has been around for quite awhile now. Quite common on North American corporate aircraft and many types of airline equipment. Try http://www.pulselite.com/
for more info.

Cheers

[av8boy]

Used to have a regular customer in a 182 who'd always make his first call as "Tower, Cessna xxx with the flashing landing lights..."

I found the flashing lights to be helpful.

Dave

[rentaghost]

Some of the newer Cessna Citations have these fitted, could have been one of these.

[Firebird]

As an AME I was lead to believe they help in avoiding bird strikes. We have several 737 and 727's in Canada that have the lights alternating from one side to the other.:p

[lucky luke]

They are used to scare off birds in order to avoid bird strikes for example during landing.

[niknak]

Also becoming more common in the UK, especially on the helicopters which undertake low level survey patrols, good for frightening off birds and alerting anyone else who happens to be in the vicinity that you're there.