David Megginson wrote
I think that the only way that a LOC or VOR approach would be
significantly easier than an NDB approach is if you were chasing the
needle: if you chase the CDI in a VOR or LOC approach, you still stay
close to track (in a constant series of S-turns); if you chase the NDB
needle, you end up approaching the NDB downwind from the track.

You got it. The other difference - with the NDB, you absolutely must
keep the DG (if available) on the correct compass heading.

I'm not nearly good enough to do a lot of mental math on any approach
(not as long as they maintain that picky requirement about not flying
into the ground), so I just leave my ADF card with north at the top
like a fixed card, and remember how far my wind-correction angle is to
the left or right, just like I do with a VOR or LOC approach. As long
as the NDB needle position is the same as my wind-correction angle,
I'm on the approach track.

How about when you're doing the procedure turn? How do you know when
to start your turn to your final approach course? More mental math?

The only difference is the fact that the ADF starts (sort-of)
reverse-sensing after station passage, so that what starts out like a
LOC approach can end up like a LOC(BC) approach. I just remember

Push the head, pull the tail

and everything usually works out fine.

More stuff to remember. The VOR needle keeps working the same way
throughout the approach.

You can teach those skills without the ADF, but without the ADF you
can get by with NOT teaching those skills, save 10 hours, and the
student can still pass the checkride.

I find it hard to believe that anyone could pass an IFR checkride by
chasing a CDI in a zigzag -- can they?

Yes. They can. I've seen it happen. Just like students who drive
the airplane onto the runway can pass the private checkride in a 172
or Cherokee, when a Cub or a Champ would eat their lunch for doing it.
I've seen that happen too.

Like I said - you don't need an ADF to teach these basic skills - and
they are basic - but without the ADF, you can get by without teaching
them, and many do.

Michael