How wide is an NDB approach course?

-----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.

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.

--
Transpose mxsmanic and gmail to reach me by e-mail.

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.

The only problem I have with trying to use a MW AM radio station for
navigation is that they don't have consistent power and radiation
patterns. Typically they'll broadcast a reasonably strong signal during
the day. However at night, because the ionospheric absorption goes down
and because the signal can skip, the FCC requires most stations to dial
their power back and change antenna patterns.

This can result in a sudden loss of signal when the sun sets. I would
advise anyone looking for NDB practice to avoid the evening hours, and
not to navigate with AM stations in actual IMC conditions unless you're
very familiar with the radiation pattern and power output of the station
you're using. Remember, AM radio stations no longer report service
outages via NOTAM, so you're pretty much on your own here.

Jake Brodsky

Jake Brodsky wrote:
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.


The only problem I have with trying to use a MW AM radio station for
navigation is that they don't have consistent power and radiation
patterns. Typically they'll broadcast a reasonably strong signal during
the day. However at night, because the ionospheric absorption goes down
and because the signal can skip, the FCC requires most stations to dial
their power back and change antenna patterns.

He clearly said for practice use, not for actual navigation. I actually
found the signal better from the radio station than from most NDBs,
but I definitely wouldn't depend on one for anything other than practice
with a safety pilot or instructor in VFR conditions.


Matt

Jake Brodsky writes:

Remember, AM radio stations no longer report service
outages via NOTAM, so you're pretty much on your own here.

Are you saying that they did this at one time in the past?

--
Transpose mxsmanic and gmail to reach me by e-mail.

I didn't know that. Thanks for the info!

Andrey


Jake Brodsky wrote:

the day. However at night, because the ionospheric absorption goes down
and because the signal can skip, the FCC requires most stations to dial
their power back and change antenna patterns.

Jim Carter wrote:



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.


Most of the NDB IAPs flown by airlines was with slaved RMI/ADF
indicators. Those approaches became seldom used by the major carriers
by the early 1960s.

-----Original Message-----
From: Sam Spade ]
Posted At: Sunday, January 21, 2007 7:32 AM
Posted To: rec.aviation.ifr
Conversation: How wide is an NDB approach course?
Subject: How wide is an NDB approach course?

....
Most of the NDB IAPs flown by airlines was with slaved RMI/ADF
indicators. Those approaches became seldom used by the major carriers
by the early 1960s.

All of my experience has been 91, 135, and 141 so I defer to those with
121 experience for that topic.

NDBs (we still called them ADFs) were still in wide use for Wichita iron
back in the early '70s and that is where my exposure started. We flew
NDB approaches quite frequently in the mid-west and plain states because
ILS was only available at major metropolitan centers and VOR was only
available at a few remote airports (like Gage, Oklahoma). There were
frequently other fields around, but there were no pub'd VOR approaches
for a lot of them so we had to use NDB.

Those approaches work just as well today as they did 35 years ago, but I
will grant you that they take more work and more diligence to execute
properly. NDB approaches are definitely not my first choice unless there
is some young pup in the right seat who's been bustin' my balls about
being an ancient aviator. Then an NDB approach can be a real humbling
experience with a good wind and maybe a few static discharges off in the
distance.

BTW, old Frontier pilots probably still have nightmares about all the
NDBs they had to fly because of all the little farm towns they serviced.