ADF or RMI?

"Stan Gosnell" me@work wrote in message
...
"Tom S." wrote in
:

All the aircraft I'm looking at have an HSI. The plane I
fly with my boss has an RMI on his EFIS, but no on the
co-pilot station. So far, we've never used it.

If you have an HSI, you certainly don't want to downgrade to an
RMI. The HSI gives you much more information and is easier to
interpret.


Thanks, Stan.

That's what I though, and I notice many of the more elaborate HSI's have RMI
indicators. I'm just wondering what the big deal is in having both, as many
aircraft do.

My original point is that RMI's seem more common nowadays, but were somewhat
rare when I began my hiatus from flying in 1989 (until this past summer). I
was under the (mistaken??) assumption that they made NDB approaches easier.

As I said, so far, I've not seen the boss use his.

I would like to know the whys and HOW's in any case.

Tom
--
"Transported to a surreal landscape, a young
girl kills the first woman she meets and then
teams up with three complete strangers to
kill again."
--Marin County newspaper's TV
listing for "The Wizard of Oz"

"Tom S." wrote in message ...


was under the (mistaken??) assumption that they made NDB approaches easier.


Yes, an RMI does make an NDB approach easier because an RMI shows
easily and intuitively your bearing to an NDB. It works very similar
to an ADF with a slaved rotating compass card. This means that
applying wind correction on an NDB approach is much easier with an
RMI.

That said, I would not recommend investing money in an RMI right now.
Not only can you get TWO electronic RMIs in a Sandel EHSI, but you can
even set up a portable Garmin 195 or 295 or 196 GPS with a bearing
pointer that functions as an RMI. If you have an IFR-legal ADF in
your airplane, it is perfectly legal to fly an NDB approach while you
supplement your ADF navigation with RMI information from your portable
GPS -- just be sure your ADF remains your primary navigational source.

--
Richard Kaplan, CFII

www.flyimc.com