Sunday, October 10, 2010

Anahim Lake

I still have the CAP I bought from renewing my IFR in BC, so that's the one I'm simming with. Anahim Lake is in the coastal mountains of BC. It has two published instrument approaches, an RNAV runway 31 and an NDB A, both from the same direction, but the latter named as a circling approach because it is 14 degrees off the straight in. If you're using the Bella Coola altimeter setting and the wind favours runway 13 in a category B aircraft (i.e. you can keep your speed down to 120 knots while circling to land) then there is only ten feet altitude difference between the RNAV and NDB MDA. That looks weird at first, but seeing as either way the crux of the procedure is circling, the only difference is how precisely the nav aid gets you to the point where you break off and circle.

I set the simulator up for take off from Bella Coola and fly AR 34 to Anahim Lake. The plate says "Use Bella Cools altimeter setting. Available limited hours." Does that mean that the procedure is not approved at all outside those times? I'm not sure. Usually there is an altitude penalty for using an offsite altimeter setting, but this one never has a local altimeter setting and when Bella Coola is closed I guess there is nothing close enough to be safe.

I'll fly the NDB approach, because I don't have a good GPS simulation in in MSFS. The MDA is 5580', so I set up weather layers from the ground to 5000' as few clouds (1/8th coverage) and light rain; from 6000' to 8500' there is 7/8ths cloud coverage and I throw in some altostratus layers above that. I leave the visibility pretty good below the clouds, probably not accurate for the area, but I can ramp it up later. The advisory visibility is 3 nm and the missed approach time is 3:01 at 120 knots groundspeed. So I need to be at the MDA 90 seconds after the beacon, but that's only 1000' to descend, so shouldn't be too bad. Bella Coola has no instrument departure, so I have to climb VFR to--yikes--11600'. This won't really work, so I cheat and turn off a couple of cloud layers until I get to the airway. Too bad I can't do that in real life. A bit of NDB tracking practice then cheat slightly by using the GPS to get a distance back and plan a descent to the MSA. It looks virtually clear below. I thought I turned my clouds back on again. I pause the game and check that both 'global' and 'local' weather are set to include the thick layer of broken cloud down to minima, as I described earlier. They are. I enter a shuttle descent at the MDA.

The weather still looks too good. I check it multiple times and shift the layers around a bit. At first there seems to be more cloud below, but as I complete the shuttle, inbound at 6600' to the beacon I can see the airport easily, so I go land at it.

I tried!

1 comment:

Aviatrix said...

Spelling corrected, Thanks Colin.