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).

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

On Tue, 16 Jan 2007 21:28:12 GMT, 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).
>
>Jose

When within 10 degrees of the published course.

> 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
--
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).
>
> Jose

A whole lot wider than an ILS. From TERPs.

b. Area. Figure 57 illustrates the final approach primary and secondary
areas. 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. A
secondary area is on each side of the primary area. It is zero miles
wide at the facility, and expands uniformly to 1.34 miles on each side
of the primary area at 10 miles from the facility. When the 5 mile PT is
used, only the inner 5 miles of the final approach area need be considered.

The required obstacle clearance is also greater than other non-precision
approaches: 300 feet with FAF, 350 without.

The FAA does not define when established on an NDB or any other course.
It is implied by the IR PTS, but that is not a precise definition.

ICAO does define such things. But, those are not valid for FAA procedures.

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).
>
> Jose

From TERPs:

b. Area. Figure 57 illustrates the final approach primary and secondary
areas. 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. A
secondary area is on each side of the primary area. It is zero miles
wide at the facility, and expands uniformly to 1.34 miles on each side
of the primary area at 10 miles from the facility. When the 5 mile PT is
used, only the inner 5 miles of the final approach area need be considered.

Also, the minimum obstacle clearance is greater than other NPAs; 300
feet with FAF, 350 without.

The FAA has never defined on course. That is up to the pilot. The IR
PTS gives some fences, but that is about it.

Bill Zaleski wrote:
> On Tue, 16 Jan 2007 21:28:12 GMT, 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).
>>
>>Jose
>
>
> When within 10 degrees of the published course.
>
There is no policy or rule to support that.

On Tue, 16 Jan 2007 16:50:04 -0800, Sam Spade >
wrote:

>Bill Zaleski wrote:
>> On Tue, 16 Jan 2007 21:28:12 GMT, 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).
>>>
>>>Jose
>>
>>
>> When within 10 degrees of the published course.
>>
>There is no policy or rule to support that.

He asked when he should consider himself established for the purpose
of descent. Have you got better guideline to follow when in a cockpit
looking at an instrument panel? In the absence of policy or rules, as
you say, what do you suggest a better answer would be?

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

> So, ten degrees from the facility puts me 2.5 miles inside the protected area.

Oops. 2.5/2 miles, or 1.25 miles inside the protected area. Pesky twos!

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

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.

> 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.
for Email, make the obvious change in the address.

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: Re: 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.

--
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

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

> -----Original Message-----

> From: Mxsmanic ]

> Posted At: Saturday, January 20, 2007 8:09 AM

> Posted To: rec.aviation.ifr

> Conversation: How wide is an NDB approach course?

> Subject: Re: How wide is an NDB approach course?

>

> 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.



Think back even further to the low frequency radio ranges. This is the
bottom range on the old Bendix coffee grinder ADFs. The LF signal could
be "heard" over an extraordinarily long distance with relatively low
power. LF was around for navigation before AM radio really found its way
into aircraft. From Wikipedia:



"These radio aids became the navigation resource for enroute airways
flying in clear and clouded weather, and for airport letdown approach
patterns in limited ceiling and visibility conditions. Fixed emplacement
of low frequency, non-directional radio beacons came into use as
distance checkpoints along airways and along airport approach patterns.
Many, but not all of these low frequency systems were superseded after
World War II by higher frequency (hundreds of megacycles instead of
hundreds of kilocycles) radio wave emitting installations known as
"omni-range" and "localizer" facilities. This changeover to higher
frequency constituted an advance in degree but not in kind."

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.

Mxsmanic wrote:
> 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?
>
I seem to recall that *charted* stations were NOTAMed when they went out
of service. However, I am not entirely sure about this.

Jake Brodsky

Bill Zaleski wrote:
> On Tue, 16 Jan 2007 16:50:04 -0800, Sam Spade >
> wrote:
>
>
>>Bill Zaleski wrote:
>>
>>>On Tue, 16 Jan 2007 21:28:12 GMT, 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).
>>>>
>>>>Jose
>>>
>>>
>>>When within 10 degrees of the published course.
>>>
>>
>>There is no policy or rule to support that.
>
>
> He asked when he should consider himself established for the purpose
> of descent. Have you got better guideline to follow when in a cockpit
> looking at an instrument panel? In the absence of policy or rules, as
> you say, what do you suggest a better answer would be?
>

When the bearing indicates on-course. 10 degrees is way too early.

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 is right at the limits without any compass or ADF error. Not a
good idea. But, it's your call

Robert M. Gary wrote:

> 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
>

With an RMI you might be somewhere in town. With a fixed card you might
not even be in the same county.

> -----Original Message-----
> From: Sam Spade ]
> Posted At: Saturday, January 20, 2007 6:46 PM
> Posted To: rec.aviation.ifr
> Conversation: How wide is an NDB approach course?
> Subject: Re: How wide is an NDB approach course?
>
....
>
> With an RMI you might be somewhere in town. With a fixed card you
might
> not even be in the same county.

Come on now Sam, you know that's not right. NDB approaches are safe and
accurate when properly executed by trained and current pilots. They have
been for years. I will grant that they take a lot more situational
awareness than letting the GPS steer the bird down the tracks, but even
so the NDB approach still works just fine.

Jim Carter wrote:
>
>>-----Original Message-----
>>From: Sam Spade ]
>>Posted At: Saturday, January 20, 2007 6:46 PM
>>Posted To: rec.aviation.ifr
>>Conversation: How wide is an NDB approach course?
>>Subject: Re: How wide is an NDB approach course?
>>
>
> ...
>
>>With an RMI you might be somewhere in town. With a fixed card you
>
> might
>
>>not even be in the same county.
>
>
> Come on now Sam, you know that's not right. NDB approaches are safe and
> accurate when properly executed by trained and current pilots. They have
> been for years. I will grant that they take a lot more situational
> awareness than letting the GPS steer the bird down the tracks, but even
> so the NDB approach still works just fine.
>
>
NDB always worked fine in my airline's simulators. My meager experience
with them on the line was from fair to poor.

Our former cold war enemies, the Soviets, make them work by
lock-stepping one NDB on the tail and one on the nose. With RMIs and
two ADFs, that did work.

Had the USAF crew that died along with Secretary Brown understood that
concept, they all would be alive today.

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: Re: 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.

Jim Carter wrote:
>

>
> 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.
>

Yes, that is why I mentioned majors. A friend of mine who flew with the
old North Central flew ADF approaches all the time. Then again, it was
in flat country.

You're right, the old Frontier had a lot of mountains without the dual
beacon setup in Eastern Europe.

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.

Andrey Serbinenko wrote:
> 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.

That's why pilots use different HF frequencies at night over the ocean.

Michael wrote:

> 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
>

What's wrong with that approach, at least until leaving MDA?

If you're referring to the snake pit below MDA when circle-to-land only
minima are published, this one is a comparative cakewalk compared to the
high HAA circling MDAs in the mountains.

Bill Zaleski wrote:

> 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.
>

If the NDB is on the nose, I would agree. If it is on the tail,
however, and the MAP is near the max distance limites, it is a crap
shoot whether you will remain in the primary area of protected airspace.

Sam Spade wrote:
> What's wrong with that approach, at least until leaving MDA?

The 1200 ft tower that you can hit. It's located outside the trapezium
that defines the protected areas (inner and outer) but your VOR
receiver can be within 4 degrees of perfect (the more restrictive
standard for the VOR check - some COR checks allow 6 degrees) and your
needle need not exceed 3/4 scale deflection (the more restrictive
standard on the instrument airplane PTS - you are allowed full scale on
the partial panel approach) to put you right into the tower.

Michael

Michael wrote:
> Sam Spade wrote:
>
>>What's wrong with that approach, at least until leaving MDA?
>
>
> The 1200 ft tower that you can hit. It's located outside the trapezium
> that defines the protected areas (inner and outer) but your VOR
> receiver can be within 4 degrees of perfect (the more restrictive
> standard for the VOR check - some COR checks allow 6 degrees) and your
> needle need not exceed 3/4 scale deflection (the more restrictive
> standard on the instrument airplane PTS - you are allowed full scale on
> the partial panel approach) to put you right into the tower.
>
> Michael
>

No doubt it is pushing the criteria, although the criteria would permit
a MAP as much as approximately 5 miles further.

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.

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

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

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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follow something, be it a leader, a creed, or a mob. Whosoever fully
understands this holds the world in his hands.
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