Is marker beacon really needed?

crabandy · #1 08-07-2012, 09:19 PM

With a GNS430W is there any need to install a marker beacon antenna to meet the legal IFR requirements?

tim2542 · #2 08-07-2012, 09:32 PM

From my reading on it (studying for the written), a certified gps can be used to locate the MB and other fixes.
Tim
2012 Dues paid

Dbro172 · #3 08-07-2012, 09:48 PM

Several approaches do not even include marker beacons (vor, ILS/loc/DME, RNAV) and increasingly it seems more marker beacons are being taken out of service. So, obviously you wouldn't need a MKR bcn to fly those approaches.

The gns430w can be used as an acceptable means of DME, therefore you can use DME to identify several fixes in IFR flight and (i think) including the MKR fix (if you needed) or a lot of times a radial can identify the MKR fix.

Axing the marker beacon locator and antenna, opens you up to a few more audio panel options (par100ex, gma 240)

BobTurner · #4 08-07-2012, 10:32 PM

An ifr approved gps is an acceptable substitute for a MB receiver, as long as the OM fix can be determined from the on board database.
Likewise, ILS or other approaches with the note "ADF required", the ifr approved GPS can sub for an ADF as long as the ADF fix is in the database.

crabandy · #5 08-07-2012, 11:23 PM

Thx for the replies. More specifically I don't think the 430 identifies the middle and inner markers, are they required for an ils? Trying to not install marker beacon antenna if I don't have to.

BobTurner · #6 08-08-2012, 12:12 AM

There was a time when a 50' penalty applied if you couldn't ID the MM. That time has long passed, no need to ID the MM. The FAA is removing them almost as fast as they can. IM are rare, pretty much associated with cat II or III.

The answer is that a localizer, glide slope, and G430/420/400 is sufficient for every ILS, at least in the US.

I personally don't have a MB receiver. Sl-30 + G420 is all you need for an ILS.

rzbill · #7 08-08-2012, 04:49 AM

Pardon the assumption but it sounds like you do not have an instrument rating yet crabrandy. Thats OK, but you might consider doing some training before finishing your panel design.

I did (finished the rating) and the training did have an influence on my panel design and underlying electrical system.

Good luck in your project.

Rick_A · #8 08-08-2012, 06:59 AM

There is no need to install a big, ugly boat type MB antenna. My audio panel has the MB function, so I installed an Archer MB antenna in my wing tip and it works great.

There are even cheaper alternatives to the Archer MB antenna. If you search the forum you will find info on roll-your-own MB antenna's that are just a piece of wire cut to the correct length, with a means of attaching a coax to run to the receiver.

For the few times that you may use the MB, the wing tip antenna is the way to go.