Re: Alternate without GPS

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barr@Colorado.EDU (BARR DOUG) wrote in
<8tpif0$h0i$1@peabody.colorado.edu>:

>I notice in the AIM there is a requirement that if you require an
>Alternate the Alternate approach must be able to be flown without your
>IFR GPS equipment working. This is true even if all you do is use the
>IFR GPS as DME or outer marker identification.

There is a difference between using an approach to determine an alternate,
& flying the approach once you are at the alternate. You can't use any GPS
approach for determining an alternate, but you can fly the GPS approach if
you do go to the alternate. The alternate if for fuel computations, &
after you take off all that stuff for alternates goes out the window. You
don't even have to go to the alternate you put on the flight plan if you
miss at your destination. ATC doesn't even know what you filed for an
alternate, thus they will ask you your intentions if you miss the approach
at your destination. You can fly the same approach again, a different
approach at the destination, or go to any other airport you want, as long
as you have enough fuel to do what you want.

>So... assuming the GPS signal from outer space is lost, and all I have
>is one VOR/GS, (no DME and no ADF in the plane), under what
>circumstances can I identify the outer marker with my VOR, or rely on
>radar vectors to the outer marker (can ATC vector me to, and call the
>outer marker).

ATC can call the marker, but almost always it's also fixed by VOR radials
also.

>Without my GPS the only approach I am sure that I could do would be a
>VOR only approach. Though in theory, I could fly to a VOR, follow a
>radial to the outer marker, switch back to the loc periodically, pick up
>the loc, fly it outbound, do the procedure turn and fly an ILS appoach
>with JUST one VOR/GS. WHEW! (I would certainly hope that I could get
>radar assistance!)

If you're flying a VOR approach, there is no outer marker. Marker beacons
are only on localizers. If there is a marker beacon, you are flying a
localizer or ILS, not a VOR approach. On VOR approaches, the fixes are
defined by radials from other VOR's or DME. Look at some approach plates.
Fly whatever the approach plate calls for.

>Anyway, how do I tell if radar services are available and if they could
>vector me to an outer marker, so I can make my Alternate legal with the
>equipment I have (IFR GPS and VOR/GS)?

Read the approach plate.

Regards,

Stan