ifr equip needed
I assume you are IFR rated at this time? If you are you know you only need the NAV equipment that you plan on using. If you are really serious about IFR you would no doubt have VOR/LOC/ILS capability and a marker receiver. Of course an IFR GPS would be nice. Some of the new IFR GPS have everything listed above in one box!
Marker beacons are associated with a LOC and ILS approach. The substitute can be a locator (NDB), crossing radial (if shown on chart) or radar can call the OM if there is radar coverage. The nice thing about the SL30 is you have a standby VOR bearing display. However not all LOC/ILS approaches publish a crossing radial to identify the OM.
91.205(d)(2) Two-way radio communications system and navigational equipment appropriate to the ground facilities to be used.
So the min IFR (com/nav) equipment would be one com radio and one VOR, and a mode c transponder, nothing else. Of course you would only be able to do VOR approaches. If your VOR receiver is a LOC receiver also (which the SL30 is and more) you can do LOCALIZER approaches without an OM if you have another way to identify the FAF, by crossing radial (if noted on chart) or radar fix by ATC. To get a crossing radial with one VOR/LOC receiver you need to switch between the VOR freq and back to LOC. Not ideal but it has been done. The SL30 as I understand it is really two nav radios in one, displaying the standby VOR bearing on the digital display while still on the LOC is shown on the NAV head? OM for the ILS is the same as the active freq (LOC approach). You can fly an ILS without the OM or sub-ed method of location, but it is not legal to my knowledge. It is required equip for these kinds of approaches. On the LOC, when you intercept the glide slope you start down. The OM is just a backup to verify proper altitude, position and start time as an optional back-up/situational awareness. With GPS map displays this is not as important as it was.
ILS, if you remember your IFR questions, "where is the FAF on an ILS approach" Many point to the X on the approach plate, but this is not true. The FAF for the ILS is at glide slope intercept and min glide slope intercept altitude. Do you even need a marker beacon for a Cat I ILS? I know the middle marker is not needed and the inner marker was never needed for a Cat I approach. What about the outer marker? Yes, you still need to be able to ID that fix somehow (radar, x-radial, GPS).
Are you going to have an IFR (TSO'ed) GPS installed to meet the C 146a (en-route only or en-route/approach) than you could ID the FAF by the GPS. However if you have an IFR GPS you would likely use that anyway and not the VOR or LOC. The ILS is still the grand dad of approaches and still they way to go to get down to 2400'-1800' RVR.
As far as audio panel it is an expensive way to get just a marker receiver. What about a kr22 or a stand-alone Cessna MB receiver. You can find them for cheap. An audio panel is nice but there are ways around that, especially when you only have one COM and maybe one NAV. Most COM radios have aux audio input so you can pipe audio from other sources, like a NAV or a warning tone. Check eBay for used audio panels for little money if you think you want one. The thin Narco or king is nice and go for less than $100, with MB receiver. PS engineering makes a cool little intercom with a built in audio panel that handles 2 coms and 2 navs.
Cheers George
