Short and sweet - what's the designation of A/B/C on a GPS IAP designate? Thank you!

GPS circling approachs.
For whatever TERPs reason the approach doesn't meet straight-ins criteria would be my initial guess.
Do you have a specific example at an airport?

USMCFLYR

Sure.

http://155.178.201.160/d-tpp/1208/05889VDGC.PDF

KASE VOR/DME or GPS-C

Why is it a GPS-C?

If I'm not mistaken, it's when there's more than 1 GPS approach for the runway, or circling, then they designate them via B/C, etc. Does that airport have more than 1 circling GPS approach? If so, then they'll all have different waypoints.

That's a good question. I was just looking at it on airnav.com and I am pretty sure their list of IAP's for each airport is complete. If so, that's the only GPS IAP into that field. Could it designate a general update (as in new waypoints or other elements of the approach) to help show the most current version?

The letters indicate the number of circling approaches to the airfield. It doesn't matter if they are based on traditional navaids or GPS.

At Laughlin, we had a TACAN-A procedure to get the T-38s in under certain circumstances. When we got an RNAV capable airplane, the Texan II, we put in a GPS-B to get the T-6s in under similar but slightly lower weather mins. The TACAN-A is out of the books, but the GPS-B stands as the second circling approach to Laughlin AFB, but is the only one in the books. The USAF publishes, names and builds approaches to the same criteria as NACO/TERPs.

When you have the Z/Y/X letters they designate approaches with slightly different ways to get to the same final approach segment. This is like the Y2K problem. What happens when civilization survives long enough to get 13 different circling approaches to the same airfield and the straight in has 13 different ways and we crash together at the letter "M"?

Hope this helps.

Interesting. That makes sense as the only other approach listed is a LOC/DME-E. Thanks!

Remember, KASE has private circling approaches available to authorized operators only. They add to the "count", but you can't access the charts unless authorized.

GF

So that's something that an operator would apply for? And would have to go through certain training?

The Operator's FSDO or POI would have to approve their use after training and proving operational safety. Airlines, typically.

GF