NDB/ADF holding question???

[BRlinepilot]

Question for you NDB know hows, what does this mean when given this holding instruction: hold on the 335 bearing from the station? Is this the same as holding on the 335 radial? OR is it the 155 radial. I know there is no such thing as a radial off of a NDB, I think. What if it's the 335 bearing to the station? SOMEONE, please help? Thanks in advance!

 

[Cornelius]

If you get a NDB holding clearance and you receive a heading, it is always going to be the inbound heading, or your bearing to the station. In your example ATC would say, "Hold NW 335 inbound, EFC _____" That's usually how you are going to get it. I hope this helps.


C-ya

 

[BRlinepilot]

I'm not clear still..... If the clearance is "hold 335 bearing FROM the station", is this still the inbound course? I'm confused about the "FROM" portion.

 

[Andy Neill]

According to FAA Order 7110.65 (the manual used to prescribe ATC procedures):

"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."

EXAMPLE-
"Three Four Zero bearing from Randolph Radio Beacon." "

So if you get a clearance to hold on the 335 bearing from XYZ radio beacon, you would hold NW of the NDB using 155 as the inbound course. You would do the same if your hold clearance was for the 155 course to XYZ radio beacon.

 

[BRlinepilot]

Dudes, thanks for your quick response!!! I thought that was the case, but wasn't sure.

 

[Cornelius]

If you look at published holds on Missed approaches, usually they always tell you the inbound course for an NDB hold.

It sounds as though Andy is right about verbal holding clearances and I better start filling out some NASA forms!

C-ya.

 

[avbug]

For assigning a bearing on a non-directional beacon, a bearing is the same as a radial. As Andy pointed out, the 360 bearing lies north of the beacon, the 180 radial lies south. If you're holding on a bearing, you're holding on the bearing that comes from the station. Your hold will be made to the station, so you'll use the reciprocal of the bearing number for your inbound leg.

 

[A Squared]

Avbug,


You wrote "a bearing is the same as a radial" which is not completely accurate. A radial is always away from the station. A bearing may be either to or from the station, and it must be stated which. (see controller's handbook excerpt above) I'm sure you're aware of this, but the way your post is worded could be misleading to someone who hasn't read the whole thread.

regards

 

[Andy Neill]

If the contolller is using correct procedure, he/she will give a "course to" or "bearing from" a radio beacon and not a "bearing to" a radio beacon.

 

[A Squared]

Andy,

You're right, maybe I need to read a little more carefully. The last time this question came up, I searched through every aviation reference I could lay my hands on. What I found was that the word "bearing" is used diffently by differnent sources. Your point is well taken that the controllers handbook specified courses to, and bearings from. As a practical matter, make sure you hear "to" or "from" the NDB in your clearence. If there's any question, request clarification.


regards

 

[avbug]

Bearing, when used in reference to a radio beacon, is the direction from the station.

When one uses the term "bearing to a station" one is actually referring to a course from the airplane to the station, rather than a station indication or reference. The same could be said of a bearing to a barn or lake. It's a course plotted from the aircraft to that object. When used in reference to aerial navigation by beacon, the using the term "bearing" in relationship to a station is technically incorrect; bearing represents the direction from the station to the aircraft.

A bearing to something is a straight line heading reference without regard to wind correction or current correction.

For uniformity, it's easiest to think in terms of radials and bearings as being the same. They aren't, in that a radial is highly directional and definable, while a bearing isn't, but consider their relationship on a RMI; they become the same.

I'm hoping that someone clicking on the thread will read the entire thread rather than just one response, as few responses are stand-alone answers.

Your final comment is the most important and critical one; if there ever exists any question, immediate clarification should be sought.

 

[lancair1]

I dissagree with a few of the statements posted above.

Here in central florida, I've found that the common frasiology is "hold north of ndb on 180 bearing to the station" Which certainly seems to simplify the mental picture and appears to be correct.

As for the meaning of bearing the aim definition is: direction to or from any point.

I believe all examples using the phrase "hold on 123 bearing from ndb" is imposible because there is no definable point while outbound from an ndb. ATC is only correct if they say "bearing to" when concerning ndb holds.

Also, the aim does suggest atc give a cardinal position of the hold. ie. hold north of ndb.