Once upon a time....

[gismo]

Think of the individual switches as redundancy. With the single avionics master switch what do you do if the switch goes bad. Of course, there is a way to wire another switch for redundancy but in practice I've never seen that done on older aircraft retrofitted with a avaionics master switch.

Len

If 1970 is "older" I can show you my Baron which has exactly that (two AV masters for redundancy). In fact I had one of the switches fail on a trip once and the backup came in real handy.

And if that's not old enough, I rigged my 1954 Bonanza with an extra switch that controlled power to the #1 navcom and loran with everything else on the regular avionics master. The navcom1/loran switch even bypassed the battery master switch so I could run those radios even if the battery master failed (single point failure in most planes) plus I could program the loran and get ATIS/clearances before starting.

 

[gismo]

Get a set of approach plates for your area and look and see how many have only NDB approaches.

Also, you can fly an NDB approach with an en route and approach certified GPS.

My opinion is that you are just not going to be in a situation where the ADF is a critical component in your panel. I could be wrong. I sometimes am.

I pulled my ADF the last time I made some changes to the avionics because I hadn't used it for anything except practice NDB approaches. That said, there are several airports that are only served by NDB approaches (with no GPS overlay). I expect that many if not all of these airports will eventually get either a stand alone GPS approach or an overlay but who knows when that will be.

BTW you cannot legally fly a NDB approach under IFR with a GPS unless the title is "GPS or NDB..." AFaIK there's no technical reason for this beyond the lack of flight testing.

In any case I'd leave the ADF in the panel until I upgraded to a IFR approach certified GPS.

 

[Toby]

If 1970 is "older" I can show you my Baron which has exactly that (two AV masters for redundancy). In fact I had one of the switches fail on a trip once and the backup came in real handy.

And if that's not old enough, I rigged my 1954 Bonanza with an extra switch that controlled power to the #1 navcom and loran with everything else on the regular avionics master. The navcom1/loran switch even bypassed the battery master switch so I could run those radios even if the battery master failed (single point failure in most planes) plus I could program the loran and get ATIS/clearances before starting.

Sorry I haven't responded to yours and Len's posts. I don't understand the finer points of wiring. I thought the one master switch turned everything on (a convenience), but you could still turn things on and off individually even if you had that switch.

 

[Ken Ibold]

Sorry I haven't responded to yours and Len's posts. I don't understand the finer points of wiring. I thought the one master switch turned everything on (a convenience), but you could still turn things on and off individually even if you had that switch.

You can ... unless the switch itself fails OFF, then you can't turn anything on.

 

[Toby]

I pulled my ADF the last time I made some changes to the avionics because I hadn't used it for anything except practice NDB approaches. That said, there are several airports that are only served by NDB approaches (with no GPS overlay). I expect that many if not all of these airports will eventually get either a stand alone GPS approach or an overlay but who knows when that will be.

BTW you cannot legally fly a NDB approach under IFR with a GPS unless the title is "GPS or NDB..." AFaIK there's no technical reason for this beyond the lack of flight testing.

In any case I'd leave the ADF in the panel until I upgraded to a IFR approach certified GPS.

Lance,

In your second paragraph above, what title is that?

I am confused by all the discussion about ADFs and NDBs. I need to read something general about the types of approaches there are and why you find some of them at some airports and others at others. Maybe the choice(s) you find at a particular airport determine whether or not you want to fly there IFR. Right now I can't make an intelligent decision about any of this, since I don't know what I'm talking about yet.

Right now, the little knob that holds the ADF antenna is still on, but the panel unit is in my car. If I'm not going to use it, I'll get rid of it.

 

[Toby]

You can ... unless the switch itself fails OFF, then you can't turn anything on.

Oh. Thanks, Ken.

 

[Len Lanetti]

If 1970 is "older" ...

Lance,

I would venture a guess that your installation method is the less common way that avionics master switches are retrofitted. Better yes but from my observation not typical.

Len

 

[gismo]

Lance,

In your second paragraph above, what title is that?

I am confused by all the discussion about ADFs and NDBs. I need to read something general about the types of approaches there are and why you find some of them at some airports and others at others. Maybe the choice(s) you find at a particular airport determine whether or not you want to fly there IFR. Right now I can't make an intelligent decision about any of this, since I don't know what I'm talking about yet.

Right now, the little knob that holds the ADF antenna is still on, but the panel unit is in my car. If I'm not going to use it, I'll get rid of it.

That "title" referred to the title of the approach, found on the top of the approach diagram in big bold letters. Examples are: NDB 31 IE NDB(ADF) approach to runway 31, VOR 22 etc. Many such titles list two or more nav systems. If the word "or" separates the nav types (VOR or GPS 31) then you can fly it using only one of the systems listed, but if the separator is a '/' (VOR/DME 22) you must use both. A large percentage of the NDB and VOR approaches were updated to include the words "or GPS" in the title and these are called "overlay" GPS approaches meaning the FAA added the ability to fly them with an IFR approach approved GPS without having an ADF in the plane. There are also quite a few approaches that only have NDB in the title and these cannot be flown unless you have/use an ADF. Most of those approaches (NDB only) exist at airports where there are other approaches that don't require an ADF, but there are exceptions. The last time I checked there were at least a half dozen airports in my state that only have a NDB approach with no GPS overlay and now that I don't have an ADF in the plane I cannot fly an approach into any of them.

 

[Toby]

Lance, that clears it up nicely!

 

[Bill]

Right now, the little knob that holds the ADF antenna is still on, but the panel unit is in my car. If I'm not going to use it, I'll get rid of it.

Really boils down to what and how you want to learn when you do your IR. I elected to learn using "traditional" approach methods, including NDB approaches, and will learn GPS approaches after the checkride.

What I like about traditional nav methods: once you've learned to use VOR's, AFD's, and LOC/GS, you can jump in just about any plane and be up and using those nav aids in a few minutes.

What I dislike about GPS: every gps vendor has a different user interface, so knowing Garmin does you squat for flying approaches with King, etc. I wish GPS navigation skills were as standardized and portable as the "traditional" nav methods.