Approach lights help
 

I'm having a hard time explaining to a student the differences of the approach lighting systems. does anyone have a good way of explaining them that's easy to remember?

I always just find a picture of all of them on google or something and show the student. Let them figure out a way to differentiate between them in their own way. I haven't been at it long but it has worked for me so far. Good luck.

I usually break them down in to "Families" For instance, ALSF-2/ALSF-1/SALSF are all roughly in the same "Family." Same with MALSR/SALSR. Then in each family you can add or remove a sequencial flasher/RAIL to change them around a bit.

In reality, 95% of the time an airport has either MALS(R) or ALSF-2. I've only found ALSF-1 at military bases and any other variants are hit or miss.

When I teach them, I start with ALSF-2 since it is the most complex and show how you can get ALSF-1 and SALSF from it. Then I go to MALSR and show how it can also get changes (such as it just being a MALS).

Something else I do is put them in our FTD with a visual display and have them shoot the ILS on a clear day and as they get close I pause it and show them different types. Then I have them shoot it again with lower vis (around 1 mile) and see if they can identify which one and how to use it (red bars = lower).

When I was a student, flash cards were always good for me but I find most people don't like flash cards. For what ever reason, they worked great with me but not so much with other people.

Hope this helped

Important to note that ALSF-1/2 Red Side Bar / Terminating Row lights can fulfill the requirement to descend below 100'.

http://www.faa.gov/air_traffic/publi.../FAC/1006.html

Navigation Services - Lighting Systems Group
(This one has some pictures - but I've seen better ones elsewhere)

I thought that the book EEftPP explained everything well (pgs 73-75)

USMCFLYR

interesting point.. reference?

91.175c3i

"[at least one of the following visual references...] The approach lighting system, except that the pilot may not descend below 100 feet above the touchdown zone elevation using the approach lights as a reference unless the red terminating bars or the red side row bars are also distinctly visible and identifiable."

Basically if you are flying an ILS and at DH (200AGL) you see just white approach lights of an ALSF-2, you can go down to 100 feet above TDZE. If at that point you see the red lights, you can go all the way down. The way I like to show that to my students is the red side row bars basically become the touch down zone marking lights. So as you fly it they go from red ("Don't touch down on me yet!") to white ("Okay, I am runway, now you can touch down").

Point of note. I have ran a simulation like the one I described above where at DA you only had the white approach lights insight and then at 100 feet above TDZE you had the only red side row bars (but NOT the runway) in both MS Flight Sim and XPlane. In order for it to do that, I had to set the visibility to less than 1/5 of a mile. As a reminder to most GA pilots, you still need the prescribed minimums to land and most ILSs, even if they have ALSF-2 (which means they are part of a cat II/III ILS), have cat I mins of 1/2mile or 2400 RVR. And while one could claim "I determined I had the required inflight visibility" if they have ALSF-2, they most likely have RVR and a fed could probably use that against you if he wanted.

Yes, ALSF 1 and 2 are there for CAT-II/III operations.

ALSF-1 is the standard system for Cat I approaches (though can be approved for Cat II ops by appropriate authority), ALSF-2 for Cat II and III.

USMCFLYR

I'm still a bit confused with a few questions. Which one's have the "running rabbit"? So for a CAT 1 approach, a pilot can descend to 100' above TDZE provided the RVR (2400), ceiling requirements (200'), and the red terminating bars or the red side row bars are also distinctly visible have been meet with an ALSF-1? Or is this rule regardless of what ALS the runway is equipped with?

On an actual Cat III, by the time you're low enough to see the "rabbit", it's already behind you.

You said, "I'm still a bit confused with a few questions. Which one's have the "running rabbit"?"You said, "So for a CAT 1 approach, a pilot can descend to 100' above TDZE provided the RVR (2400), ceiling requirements (200'), and the red terminating bars or the red side row bars are also distinctly visible have been meet with an ALSF-1?"

Another cool and useless fact for those actually shooting low min approaches. As Meteor said, SF = sequenced flashers which will run all the way to the decision bar (horizontal row of lights 1,000 feet from the threshold.) Where approaches such as MALSR have runway alignment lights. RAIL is essentially the same concept but terminates somewhere between 200-400 feet prior to the decision bar. Also, for those of you with lightning fast brains, the distance between the approach lights varies so you can calculate in flight visibility. ALSF 1&2 are spaced at 100 ft and MALSR, MALSF, SSALR, etc.. are spaced at 200 feet.

So all of this being said, what should occur simultaneously when you reach the DECISION bar?

Actually, the "F" alone is for sequenced flashing lights. There are MALS, MALSF, and MALSR systems. To further complicate matters, an ALSF II can be operated as a MALSR / SSALR. A MALSR / MALSF can also be operated as a MALS.

Now tell me how many feet are between runway edge lights and we'll see the debate intensify....

X