How wide is an NDB approach course?

Sam Spade wrote:
The real issue here is a simplistic flight test standard that is written
in terms of an on-airport VOR or one within 5 or 10 miles of the airport.

Correct. The PTS is the problem.

When you are flying an IAP away from a VOR station and the FAF is 20 to
25 miles out, with the final going out further, you had darn well have
the CDI centered or at least touching the centered doughnot.

Right. Because depending on which VOR check you use, errors of up to 6
degrees are acceptable. The tower is something like 8 degrees off the
FAC. If the needle is centered, it is still OK.

A sharp
CFI who understands all that would not accept PTS minimum performance on
a extreme distance VOR approach.

Right again - but that presumes the CFI understands the TERPS criteria
used to design the approach. Most do not. Nor would they need to, if
the PTS was written in such a way as to match TERPS. But it's not.
This is disfunctional. The PTS should be written in such a way that,
as a very minimum, it would not be possible to meet PTS standards on a
properly designed approach with properly working equipment and still
slam into an obstruction. It's not that hard.

Michael

Michael wrote:



Right again - but that presumes the CFI understands the TERPS criteria
used to design the approach. Most do not. Nor would they need to, if
the PTS was written in such a way as to match TERPS. But it's not.
This is disfunctional. The PTS should be written in such a way that,
as a very minimum, it would not be possible to meet PTS standards on a
properly designed approach with properly working equipment and still
slam into an obstruction. It's not that hard.

Michael


I agree completely. The PTS is written by a different FAA than the FAA
that writes TERPs. Sadly, it will never change.

Doug wrote:
The other nice thing is you could use the local AM radio for VFR
navigation into Podunk, and catch the hog report and find out what's on
sale at Burford's hardware too!!

Now of course it's useful to listen to ball games and give you a heads
up on the stadium TFR.

Mxsmanic wrote:

Matt Whiting writes:


That is pretty neat. Yes, I used 1490 in Wellsboro for practice at N38.
It isn't exctly aligned with the runway, but is close and we made up a
little home-made approach for practice. It worked well.

I think the NDB concept was deliberately designed with this in mind,
so that ordinary radio stations could be used for emergency navigation
in a pinch. The frequency range is the same as AM radio, and I hardly
think that a coincidence.

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Just ran across this (from Instrument Procedures Handbook, FAA-H-8261-1,
page 4-6):
------
The International Civil Aviation Organization (ICAO) definition of
established is considered as being within half full scale deflection
for the ILS and VOR, or within +/- 5 degrees of the required bearing
for the nondirectional radio beacon (NDB).
------


Andrey


Jose wrote:
When within 10 degrees of the published [NDB approach] course.

Thanks. I take it the course is then 20 degrees wide, with some lesser
protected area on the outskirts.

Jose

Just ran across this (from Instrument Procedures Handbook, FAA-H-8261-1,
page 4-6):
------
The International Civil Aviation Organization (ICAO) definition of
established is considered as being within half full scale deflection
for the ILS and VOR, or within +/- 5 degrees of the required bearing
for the nondirectional radio beacon (NDB).

Thanks. That's very intersting and helpful.

Jose
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