How wide is an NDB approach course?

That's a lot of math to try to acomplish during an NDB approach.
Sounds like you are measuring it with a micrometer and cutting it with
an axe. You need much simpler personal guidelines when you take this
stuff into the cockpit.

I don't accomplish this math during an NDB approach. I accomplish it
here, once, on the ground. Now I have a rule-of-thumb (established at
10 degrees) to carry with me on all NDB approaches.

Jose
--
He who laughs, lasts.
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On Wed, 17 Jan 2007 19:38:04 +0000, Peter
wrote:


Bill Zaleski wrote

When within 10 degrees of the published course.

That's not a lot, since NDBs can be anything up to 30 degrees off,
IME. My local one certainly can be; it's on a coast (SHM at EGKA). But
that IAP is also DME-based.

An NDB is to a shotgun, as an ILS is to a rife with a scope. It's a
let down to an area of probability at a safe, conservative altitude.

An NDB is to a shotgun, as an ILS is to a rife with a scope.

Well, yes, but they =are= designed with numbers.

Jose
--
He who laughs, lasts.
for Email, make the obvious change in the address.

Jose wrote:
What is the protected area under an NDB approach course? Since the
course guidance is cruder than an ILS, I'd expect it would be wider, but
how much wider? I ask also in the context of when I should consider
myself "established" on course (for purposes of descent).

If, when reaching the MAP, you are in the same city as the airport you
count yourself luck.

-Robert

Sam Spade wrote:
When within 10 degrees of the published course.
There is no policy or rule to support that.

Yeah, the FAA is so incredibly disfunctional that it is literally
possible to have a 'properly' (meaning in accordance with TERPS)
designed approach flown 'correctly' (meaning to the level required to
pass the instrument rating ride as per the PTS) with functional
(meaning working well enough to pass the mandated operational checks)
equipment, and still slam yourself into something.

Check out the LVJ VOR-B.

Michael

-----Original Message-----
From: Robert M. Gary ]
Posted At: Friday, January 19, 2007 12:20 PM
Posted To: rec.aviation.ifr
Conversation: How wide is an NDB approach course?
Subject: How wide is an NDB approach course?


....
If, when reaching the MAP, you are in the same city as the airport you
count yourself luck.

-Robert

I realize a lot of the responses are written in humor, but lest some of
the younger readers get the wrong impression - it is still possible to
properly execute an NDB approach and safely arrive if the weather is
above published minimums. Hundreds of pilots flew LF range and NDB
approaches for many years without killing themselves or their
passengers.

Just because the technology has advanced to what we have today with WAAS
GPSs and XM weather and roll-steering autopilots doesn't mean that the
old NDB approach is inherently unsafe.

I believe the unsafe aspect of the system is the lack of training in
modern curriculums and our lack of practice with the equipment.

Within 10deg is pretty simple guidance in my book!

Bill Zaleski wrote:
On Wed, 17 Jan 2007 04:57:04 GMT, Jose
wrote:

[You're established inbound on an NDB]
When within 10 degrees of the published course.
There is no policy or rule to support that.

Taking Sam Spade's TERPs quote,

The primary area is longitudinally centered on the FAC, and is 10 miles long. The primary area is 2.5 miles wide at the facility, and expands uniformly to 6 miles wide at 10 miles from the facility.

I draw a little diagram, and find that the angle along the outside of
the primary area to be atan(((6/2)-(2.5/2))/10) = atan(7/40) = 10
degrees. So, ten degrees from the facility puts me 2.5 miles inside the
protected area. Sounds good to me. Start on down.

Jose

That's a lot of math to try to acomplish during an NDB approach.
Sounds like you are measuring it with a micrometer and cutting it with
an axe. You need much simpler personal guidelines when you take this
stuff into the cockpit.

I believe the unsafe aspect of the system is the lack of training in
modern curriculums and our lack of practice with the equipment.

This reminded me of a useful training aid that I've put together
some time ago. It is a known fact that any AM radio station can
serve as a radio beacon that an ADF can be tuned to. AM radio
stations are everywhere, unlike real NDB transmitters, and they are
just as good for practicing NDB work as any NDB. So, I have
downloaded a list of AM-transmitting antenna from FCC, along with
their lat/lon, callsign, and output power, and transformed it into
a google-earth file. Then I zoomed-in on the area of my interest
in google-earth, and printed the map with the stations. Very handy
for NDB practice. Here's a link to the google-earth file containing
all AM-transmitting antenna within 1000km radius of NYC:
http://tinyurl.com/35rdez
If anyone wants such a file for some other part of the US, just let
me know, and I'll generate it and put it online.



Andrey

Andrey Serbinenko wrote:

I believe the unsafe aspect of the system is the lack of training in
modern curriculums and our lack of practice with the equipment.


This reminded me of a useful training aid that I've put together
some time ago. It is a known fact that any AM radio station can
serve as a radio beacon that an ADF can be tuned to. AM radio
stations are everywhere, unlike real NDB transmitters, and they are
just as good for practicing NDB work as any NDB. So, I have
downloaded a list of AM-transmitting antenna from FCC, along with
their lat/lon, callsign, and output power, and transformed it into
a google-earth file. Then I zoomed-in on the area of my interest
in google-earth, and printed the map with the stations. Very handy
for NDB practice. Here's a link to the google-earth file containing
all AM-transmitting antenna within 1000km radius of NYC:
http://tinyurl.com/35rdez
If anyone wants such a file for some other part of the US, just let
me know, and I'll generate it and put it online.

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.

Matt

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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