Question about NDB's

[flylike44]

Much to my chagrin, I realized today that I have been teaching NDB bearings incorrectly. I have always taught that bearings are like radials (ex: If you are heading 180, and the adf(fixed card) is pointing to 360, then you are on the 360 bearing inbound---just like a vor). Now I know that I'm wrong, and I want a good explanation why. I have re explained this to my current students and none had a problem with it. And actually, my way helps with situational awareness as it pertains to position in relation to the station. Anyway, an explanation that would work for a student would be greatly appreciated.

 

[PCL_128]

Much to my chagrin, I realized today that I have been teaching NDB bearings incorrectly. I have always taught that bearings are like radials (ex: If you are heading 180, and the adf(fixed card) is pointing to 360, then you are on the 360 bearing inbound---just like a vor). Now I know that I'm wrong, and I want a good explanation why. I have re explained this to my current students and none had a problem with it. And actually, my way helps with situational awareness as it pertains to position in relation to the station. Anyway, an explanation that would work for a student would be greatly appreciated.

Actually, according to the ATC handbook, you were right to start with. We had a huge debate about this when I was instructing. We ended up calling the Miami ARTCC and getting a copy of the ATC handbook to see how controllers are supposed to issue NDB holds and intercepts. The handbook states that all bearings should be read just as a radial is for a VOR. If you are on a 360 hdg going straight for the station, you are actually on the 180 bearing.

Call your local ARTCC and ask them to fax you a copy of this section of their manual. It should clear things up for you.

 

[flylike44]

Thanks PCL....Like I said, it does help out with situational awareness, but if I'm wrong, then a non published ndb hold could be ugly....

 

[172driver]

You're both technically correct. The ATC bible (7110.65) does state that all bearings shall be from the station. Otherwise, your clearance should read 'course to' the station. e.g. 'Hold on the 270 bearing from the station' OR 'Hold on the 090 course to the station.'

However , I don't often see this taking place in the real world of ATC communications. You are likely to be told to hold on the 090 bearing to the station. Technically incorrect but perfectly clear nonetheless. As long as they include the 'to' or 'from' in the clearance, it doesn't matter to me if they call em courses or bearings. I teach my students 'bearings to' and 'bearings from' and explain that if only a bearing is given, without a to/from, they will consider it to be a from.

ATC: Hold on the 090 bearing to the station.

Know it all CFII: You mean the 270 bearing, right?

ATC: Negative, sir, I said the 090 bearing to the station.

Know it all CFII: I think you meant the 090 course.

ATC: Grrr, sir, just hold at your discretion.

Well-meaning Student: Approach, did you want us east or west of the station? We need an EFC time. What direction do you want us to turn?

<CFII breaks student's wrist prying it off the PTT>

It is a popular argument and we actually had our IR ground instructor in tears over it. She left our class, never to return. Another great example of book knowledge vs. real world practice.

It is worth pointing out that ATC will usually, as they should, provide a cardinal direction as well as a bearing/course, taking all ambiguity out of the clearance. e.g. 'Hold west of the XYZ NDB on the 090 bearing to the station.' This could also be '270 bearing' or '090 course' but the west part clarifies it. Everybody thoroughly confused? Greaaat.

 

[PCL_128]

Thanks PCL....Like I said, it does help out with situational awareness, but if I'm wrong, then a non published ndb hold could be ugly....

Yeah, I'm not sure how good my non-published NDB holds would be nowdays either. That FMS really starts to spoil you after a while.

If ATC issues the clearance the way their manual instructs, then a holding clearance should include a cardinal direction you would be holding in reference to the NDB. A correct holding clearance for a non-published hold would sound like this:

"Delta 746, hold East of the Spenc LOM on the 090 bearing from the station, left turns."

This holding clearance gives you all the info you would need to figure out the hold without having to worry about how the controller interprets bearings (to or from). That is how the ATC handbook describes a proper holding clearance.

Of course, 99.9% of the time you will receive a published hold in the real world, so all of this is moot. This is all just for the training environment.

 

[172driver]

You beat me to it while I was editing.

 

[bobbysamd]

NDB confusion

Another way to remember it is that a "bearing" is a course to the NDB. NDBs do not have radials; VORs have radials.

I dunno if the holding clearance written above sounds valid. I would query ATC about it because it sounds ambiguous, at least to me. Of course, one should query ATC anytime it gives ambiguous instructions.

ATC: "CrapAir 100 hold East of the Spenc LOM on the 090 bearing from the station, left turns."

CPT: "Sir, do you mean hold East of Spenc on the 270 bearing to the station, left turns?"

Get it on the tape. CYA. You have a duty to clarify with ATC.

I recall getting two real holding clearances. At least one was non-published, where we were instructed to hold at a DME fix. I believe that ATC gave us leg length, so no timing was needed. Very easy, with a direct entry.

 

[tarp]

I'll never forget the Baltimore Controller who came to one of those aviation seminars back in my early days. Our Instrument ground school was the same night and we all went to the seminar. We tried to get this controller (who used to direct military pilots in some hairy stuff before coming to the commercial world) in the bearing/radial controversy.

"Son", he answered one of us, "Radials radiate from and bearings bear TO. That's the only way you're gonna hear it from me and nothing else matters". (LOL)

22 years of IFR flying and I've had 1 (one) NDB hold issued to me "as published" by ATC. And back in those days, that same controller and many of his companions who actually understood NDB approaches would issue "Join the 220 Bearing to the station, cleared for the approach".

 

[midlifeflyer]

Re: Re: Question about NDB's

The handbook states that all bearings should be read just as a radial is for a VOR. If you are on a 360 hdg going straight for the station, you are actually on the 180 bearing.

No, the ATC Handbook says,

d. Nondirectional beacons. State the course to or the bearing from the radio beacon, omitting the word "degree," followed by the words "course to" or "bearing from," the name of the radio beacon, and the words "radio beacon."

The handbook is available online at
http://www1.faa.gov/atpubs/ATC/INDEX.HTM

This particular section is at: http://www1.faa.gov/atpubs/ATC/Chp2/atc0205.html#2-5-2

 

[100LL... Again!]

PCL brings up the best point-

Since direction from the fix is given, I.E. east, north, then there should be little confusion.

However, since this i an ill-defined area, I would simply verify what the inbound course is with ATC. Can't hurt for the one time in my life where I might get a random NDB hold. I keep hearing that NDB's will all be shut off in a few years. Anyone?


Here's a good one:

Hold southwest of the ABC vor 045 radial 15 DME.

What's the inbound course?

 

[flylike44]

correct me if i'm wrong, but there's no way to hold south west of a station on a 045 radial....i'm growing more confused with each passing moment...Wouldn't it have to be the 225?

 

[flylike44]

by the way, i know you'd probably never get a non published ndb hold...just my own morbid curiousity....

 

[midlifeflyer]

correct me if i'm wrong, but there's no way to hold south west of a station on a 045 radial....i'm growing more confused with each passing moment...Wouldn't it have to be the 225?

That's correct. But on an NDB hold, you =can= hold southwest of the station on the 045 bearing to the station.

 

[flylike44]

exactly. my question is, aren't you on the 225 bearing inbound to the ndb heading 045?

 

[flylike44]

and remember, this is in reference to a non published hold. would you be told to hold south west on the 225 bearing?

 

[PCL_128]

exactly. my question is, aren't you on the 225 bearing inbound to the ndb heading 045?

That's correct. You're holding SW on the 225 bearing from the station. The inbound course (no-wind hdg) would be 045. Clear as mud?

 

[flylike44]

Just called the fsdo here in san antonio. they said that the controller would specify a hold on a radial(even though i made it perfectly clear we were talking non published ndb holds). when i corrected him and said bearing, there was silence and then he repeated that the controller would specify a radial. WTF? probably won't be calling those guys with anymore questions.

 

[100LL... Again!]

Answer to my quiz:

The original clearance:

Hold southwest of the ABC vor 045 radial 15 DME


Read the clearance very carefully - it is a valid clearance. You are not cleared to hold SW of the vor. You are cleared to hold SW of the 15 dme fix on the 045 radial.

Inbound course is 045.

The fix is not always the station - here it is a dme fix.

 

[PCL_128]

Hehe. I misread your clearance. I thought you were looking for 15 DME legs. Now that I know you meant a DME fix, it makes perfect sense.

 

[100LL... Again!]

Write when I point to not clearly make sometimes.

Lessons taking writing smarter look make me.

 

[midlifeflyer]

Write when I point to not clearly make sometimes.

Lessons taking writing smarter look make me.

Ah! That explains it!

 

[100LL... Again!]

But it still was a valid clearance.

 

[midlifeflyer]

100LL... Again! said
But it still was a valid clearance.

Yes, although arguably the controller giving the clearance didn't use approved phraseology. (Your point about Write when I point to not clearly make sometimes) From the ATC manual:

"HOLD (direction) OF (fix/waypoint) ON (specified radial, course, bearing, track, airway, azimuth(s), or route)."

which would translate to

"HOLD (southwest) OF (the 15 DME fix) ON (the 045 radial of the ABC VOR)."

There are a couple examples of this in the instrument knowledge test.