Tuesday, December 13, 2005

ALSF-2 Category II and III High intensity

ALSF-2 is big airport approach lighting. It has white centre bars starting 2400' from the runway. It has sequenced flashing lights. It has red bars flanking the centre, and extra little white bars five hundred feet from the threshold. It would probably have naked dancing girls, too, if it weren't for the problem of fitting them into the forest of lighting fixtures. That and the pilot distraction factor.

Further back from the runway, the lights are on towers, up to about ten feet or so tall. Sometimes the towers are sticking out of the water when the approach is over the shore. In a smaller airplane the lights are so bright you can get to thinking that you are going to hit the towers, but you don't, and the specifications have allowed for that, requiring the towers to be frangible. That means that they're supposed to break off easily if you hit them. Don't tell your local vandals.

Now I'm completely dazzled by all the different sorts of lights. There are only two things left. One is the code RR, which represents the lowest of low tech runway lighting: retroreflective markers. Yes, you're allowed to land on a runway that is delineated only by reflectors.

The other sort of lighting that I've always skimmed over with a mental "whatever" turns out to be heliport lighting. If it starts with F it's floodlighting: high mount (FH), low mount (FL) or portable (FP). If it starts with R it might be yellow take-off and landing area lights (RY), white arrival and departure hover area lights (RW) or take-off and landing area floodlighting (RF). DR represents a line of five yellow or white lights leading into the landing area. One of the good things about not being licenced to fly a helicopter, is that no one ever expects me to land a helicopter in an unfamiliar area in the dark. I think I would hate that.

That's all the lighting types I know about. If anyone knows the history of what happened to lighting types AB, AG, or AH, I'd be happy to hear about it.


Avimentor said...

Does Canada use ALSF-1 approach lighting?

Anonymous said...

What became of Ground School with Badger?

Aviatrix said...

The Badger chief pilot told me I have too much experience, and should go to Air Canada. Thanks.

I had a ground school with Ichneumon Flight Services, and I've told you a bit about that.

If you're asking whatever came out of that, well, it's put my name on a different list, is all.

Aviatrix said...

I have to admit to not being exactly clear on the difference between ALSF-1 and ALSF-2. The approach plates note AL, and then you can see if it has the Special Flashy lights or not.

Avimentor said...

Check out:


The illustration in the AIM is in black and white, but the ALSF-1 in the US has a single row of red lights right before the row of green lights at the threshold. In the US, ALSF2 has two red side rows.