What to do when not receiving a VOR

[Cyrus]

So I flew SFO to SNA a few days ago, and this happened...

I had the PORTE5 departure and everything was (more or less) hunky dorey getting to and from WOODSIDE. However, once at WAGES, I wasn't able to pick up the FELLOWS VOR... and I was well above the MEA of FL200. This isn't really surprising, since it is 146nm away from WAGES, but I'm wondering why the route was constructed in such a way that a final transition VOR is so far away...?

I should add that I'm not using the GPS/FMS, so I always file with /A equipment suffix. (Perhaps the plate assume GPS equipment?)

Anyway, I ended up telling ATC that I wasn't receiving the VOR and he gave me a heading to hold until I could pick it up, which, as you can see, worked out ok.

What am I missing?

[gavink42]

Not sure that you missed anything.

It looks (to me) that FLW is a low-altitude VOR, which would have a service volume of only 40nm.

Not sure why they would have created such a leg on the DP.

[twharrell]

That seems to be an FSX/P3D flaw, because I had the same issue flying a different aircraft. What I did was fly what I thought was the correct heading, but dialed in the Avenal VOR into Nav2 to use for my DME until the Fellows VOR signal was picked up on Nav1. I notified ATC of my intentions so they knew the situation, and everything worked out OK. I notified ATC again when I could pick up Fellows.

Todd

[Mark Hargrove]

Gavin is absolutely right -- FLW is an low-altitude VORTAC and is only valid out to 40NM below 18,000'. I don't know how much range you might gain by flying at FL200, but I can't believe it goes from 40-ish miles (I'm sure the real range is better than that, but still...) up to nearly 150 miles just because you're 2000' higher.

It seems to me that it's a flaw in the departure, and a fairly serious one. I'd love to hear from Peter Grey about this one.

-M.

[Pieces]

I may be mistaken here, but I think that the service volumes in general apply to random point to point navigation. You shouldn't make a flight plan from VOR to VOR with leg distances greater than service volume + service volume because you won't be guaranteed reception. For a charted route, though, the reception of the navigation aid has been flight tested. Even though that leg is outside of the normal service volume, the FAA has found reception to be sufficient at the MEA for that section of the departure.

The problem here is that the simulator doesn't know that. It just models VOR reception as a function of service volume.

EDIT: Source: AIM 1-1-8.a-d (scroll down a bit)

[Peter Grey]

I'd love to hear from Peter Grey about this one.

Well that makes me feel important.

Ok, here's what's going on.

I may be mistaken here, but I think that the service volumes in general apply to random point to point navigation. You shouldn't make a flight plan from VOR to VOR with leg distances greater than service volume + service volume because you won't be guaranteed reception. For a charted route, though, the reception of the navigation aid has been flight tested. Even though that leg is outside of the normal service volume, the FAA has found reception to be sufficient at the MEA for that section of the departure.

The problem here is that the simulator doesn't know that. It just models VOR reception as a function of service volume.

Is 100% correct and pretty much what I could post on it.

Note that rule of thumb applies to any route of any kind (airways, approaches, stars, etc).

That seems to be an FSX/P3D flaw,

Along with an X-plane flaw. Most of these sims only model the exact service volume as that's all they can do short of looking up every single procedure and adjusting VORs 1 by 1 (which would take way too much time).

[Cyrus]

Thanks for all the replies. That's very helpful.

Even the OFFSHORE SEVEN SID has some pretty long distances in it.

I'm starting to like the look of the EUGEN EIGHT Departure (even though it only gets you to BSR).

[Keith Smith]

The reception distances are actually specified on a per-VOR basis in the xplane navigation database (I only recently discovered this), so it's possible to fix them as you run into cases where certain procedures aren't flyable when they actually should be.