After several questions I posed yesterday and having received great anwers from several of you, I tried an IAN approach to MWCR (Grand Cayman) which only has VOR/DME or GPS in the NGX database. Since there is only scant info in the FCOM on this it was going to be a trial and error attempt at best. So let me detail what I learned. After ATC announced the runway in use and before my final arrival fix I selected the VOR/DME to Rwy 26 in the FMC with GS=ON and it put in a discontinuity between my final arrival fix and the initial approach fix that FMC would not allow me to close. I waited until I was almost upon the last arrival fix and changed FMC to direct to IAP and it allowed it at this point. FMC immediately turned GS to OFF so I had to reselect RWY 26 and set back to ON. I set both navs to the VOR freq and used the course setting it recommended rather than what I had showing on the charts. I attempted to activate both CMD's but it would only allow me to use one or the other but not both. I put APP on and it armed FMC and GP in the annunciator panel. I had neglected to adjust speed settings in the FMC, however, so I found it was flying me at 240K with ASI blanked out. I readjusted FMC putting in speeds at each fix and noticed that it was now flying me straight to the VOR (since it was a VOR/DME approach, duh!) but was not displaying a descent angle until after the VOR. Didn't really pay much attention to that until I continued flying the approach and noticed that though it had captured the FMC course it failed to capture the GP and continued to fly at 1500 ft (the FAF crossing altitude) with GP still showing as "armed". I flew the Miss procedure and reset FMC for the approach and this time deleted the VOR point in the FMC so I had nothing between the FAF and the RWY. It now adjusted my course to rwy heading so I changed the course in both Navs accordingly. I now had a straight-in and aligned with runway. Can't beat that and this time it put in correct descent angle of 2.9^ and captured both FMC and GP. The GP did not show up on the PND as it would in an ILS, but it did on the PFD and when it captured it - it descended as if an ILS but it brought me way above the PAPI glide path and at MAP I was way too high to complete the landing on such a short runway. Another Miss but this time I set the ALT to the RUNWAY ELEVATION instead of the MDA and it correctly adjusted the flight path for a successful approach and landing. Sorry for the great detail here, but for those of you who want to try this, hopefully you will not need to repeat my initial errors. There is not any detail about the actual "nuts and bolts" of the procedure in the FCOM that I could find. Again, try this IT WORKS!

I flew the Miss procedure and reset FMC for the approach and this time deleted the VOR point in the FMC so I had nothing between the FAF and the RWY. It now adjusted my course to rwy heading so I changed the course in both Navs accordingly. I now had a straight-in and aligned with runway. Can't beat that and this time it put in correct descent angle of 2.9^ and captured both FMC and GP. The GP did not show up on the PND as it would in an ILS, but it did on the PFD and when it captured it - it descended as if an ILS but it brought me way above the PAPI glide path and at MAP I was way too high to complete the landing on such a short runway. Another Miss but this time I set the ALT to the RUNWAY ELEVATION instead of the MDA and it correctly adjusted the flight path for a successful approach and landing.

The MDA is to be considered a "sheet of glass" not to be penetrated unless the runway environment is in sight. Had you been "in the soup", and that were your only approach, would you have made it? Interesting, as I have yet to try one. Flying around CLT, ATL, and a few NE destinations lately, I've been visual and ILS with the weather.

The MDA is to be considered a "sheet of glass" not to be penetrated unless the runway environment is in sight. Had you been "in the soup", and that were your only approach, would you have made it?

Purely rhetorical, Zach. We all know that. On point, however, the IAN is designed (according to the FCOM) to bring you down to 50 ft over the TDZ, and obviously you would disconnect after the MDA but the other requirement is not only that the runway environment be in sight but also that you are in a position to complete a normal safe landing else Miss is required. On the last attempt GP would have brought me down to 50 above TCH which meant that at the MDA of 600 ft I was able to complete a normal landing by continuing to fly manually down the GP. The visual was not the issue is was that it was bringing me down to MDA just at the runway threshold!!!! The GP was somehow setting up wrongly for the approach. I really don't understand why setting the ALT to TCH should have any bearing since it does not on an ILS. Maybe another cause but it DID WORK perfectly when I set it that way. Anyway give it try. It sure is slick when it works. If you are using FSX ATC, however, it will always try to direct you to an ILS runway. I needed to choose an airport without any ILS facilities to make sure I could use the procedure on a non-precision approach.

Purely rhetorical, Zach. We all know that. On point, however, the IAN is designed (according to the FCOM) to bring you down to 50 ft over the TDZ, and obviously you would disconnect after the MDA but the other requirement is not only that the runway environment be in sight but also that you are in a position to complete a normal safe landing else Miss is required. On the last attempt GP would have brought me down to 50 above TCH which meant that at the MDA of 600 ft I was able to complete a normal landing by continuing to fly manually down the GP. The visual was not the issue is was that it was bringing me down to MDA just at the runway threshold!!!! The GP was somehow setting up wrongly for the approach. I really don't understand why setting the ALT to TCH should have any bearing since it does not on an ILS. Maybe another cause but it DID WORK perfectly when I set it that way. Anyway give it try. It sure is slick when it works. If you are using FSX ATC, however, it will always try to direct you to an ILS runway. I needed to choose an airport without any ILS facilities to make sure I could use the procedure on a non-precision approach.

Thanks Craig!