Just tried flying to KMCD in bad weather. Visibility and breakout altitude were extremely low. I was relying on the RNAV GPS 8 approach which shows a WAAS channel listed on the charts, so I figured it was WAAS compatible. I was in the RA Lancair Legacy, and never got the glideslope. Had to divert to KCIU for a good 'ole reliable ILS. Am I wrong in assuming the airport has WAAS or could there be a problem elsewhere in the ini or something?

The RNAV 8 into KMCD only has LP (Localizer Performance) MDA minimums published. In order to recieve a glide path with a WAAS approach there needs to be LPV (Localizer Performance with Vertical Guidance) DA minimums published.

Ok, thank you, looks like I have something new to learn. 

Also, make sure the unit is not indicating SUSP.

Just an update, I looked at the charts and RNAV 26 was the runway with LPV guidance, not RNAV 8 as Erich pointed out. As dumb as default ATC can be, it was clever enough in that low viz situation to assign RNAV 26 with a circle to land for runway 8. Not understanding the LPV requirement, and with the weather being below minimums for the circle to land requirement, I requested RNAV 8, but see now that wasn't a good idea. I am about to practice the circle to land for runway 8. With visibility at 4nm and clouds scattered at 1300/broken 2600/overcast at 4100, I am within legal limits for the RNAV 26 + circle to land, so this should be fun, and much less terrifying than last night. Thanks for everyone's input, this info will improve my RXP flights a great deal.  

 

Edit: Just finished it, turned out the wind was ideal for 26 w/o circling to 8, GS lighted up, and everything went great. Safe and sound at KMCD. 

As dumb as default ATC can be, it was clever enough in that low viz situation to assign RNAV 26 with a circle to land for runway 8. Not understanding the LPV requirement, and with the weather being below minimums for the circle to land requirement, I requested RNAV 8, but see now that wasn't a good idea. I am about to practice the circle to land for runway 8. With visibility at 4nm and clouds scattered at 1300/broken 2600/overcast at 4100, I am within legal limits for the RNAV 26 + circle to land

 

 

Hi Ethan,

 

I was looking over what you said... I really do not understand what was going on.  The only thing I could figure is you wanted some sort of vertical guidance to the runway.  The circle-to-land part I am confused with, because, looking at the METARs for the last 24hrs, the wind has varied from SW thru the NW.

 

Both approaches you mention regarding 26's LPV and 8's LP have nearly identical approach minima.  The circle-to-land minima are identical.  If the intent is to have vertical guidance to the circle-to-land minima (so using the RNAV 26 approach) and wanting to circle to land to Rwy 8, then one should not descent below the circle-to-land MDA.  Otherwise, a missed approach is required.

 

Again, just from a regs standpoint - you mention, "clouds scattered at 1300".  As I say, just a fwiw... you have to execute a missed approach whenever an identifiable part of the airport is not distinctly visible to the pilot during a circling maneuver at or above MDA.  This comes out of §91.175.

 

I saw that in the procedure notes that neither of these procedures are authorized at night (neither straight-in nor circling).  Interestingly enough, the VOR/DME-A is permitted at night (assuming the VGSI not inop).

 

-Rob

Flight was flown originally with historic weather for Thursday night, and then follow up flight done with live weather for yesterday iirc. That might be the source of your confusion. I chose to ignore night restrictions and fly past sunset for a more challenging approach with more reliance on instruments. I'm willing to break some rules now and then for a more interesting experience.

 

Ceiling when I originally flew was around 300ft, so I was hoping to get lucky and make it within the 350ft (ra) minimums. With circle to land minima 200ft above that, I ruled it out it in my mind as a viable option. Thought about the VOR and then kept looking at cloud ceiling, which wasn't changing as I neared the airport. So I definitely wanted a glideslope.

 

 

I'm willing to break some rules now and then for a more interesting experience.

 

 

The night restriction I found interesting... why I mentioned it.  Since it's a game... I think you allowed to break some rules. :Big grin:

 

Thanks Ethan.

hehe, no problem Rob... I try to strive for realism, but because it's a game I don't mind the occasional stretching of rules, especially if I think I could learn something from being in that situation. That said, I can completely understand the limitations put on KMCD approaches at night. That's just not something I would want to deal with at all in reality, especially in bad weather.