NDB Approach Lateral Deviation
 

I'm reviewing aviation material. I was going over instrument appr. I was wondering in Europe and other parts of the world...what is considered being laterally off course for an NDB approach to where a go around would be necessary?

I can't remember what the answer is for in the states.

I was watching this video and the video seems to imply that 8 degrees or 10 degrees is considered out of bounds and would cause a need to go around during an NDB approach.

See time mark 32:14 of this video.


Your thoughts.

5 degrees in our SOP which is ridiculously low considering how much the needle fluctuates in the real world. In the sim it's doable tho.

Your regulator will dictate what is acceptable. For example (Australian AIP):

ENR 1.5 Section 1.21.2
Can't descend on Final until "established", defined as:
Note: “Established” means being within half full scale deflection for the ILS, VOR and GNSS, within ±5° of the required bearing for the NDB, or within ±2NM of the DME arc.

Here here!

The values shown on the tabular at 32:14 are the App Procedure DESIGN

If I'm not mistaking, for NDB/VOR App, a lateral deviation exceeding 5° calls for a GA

With those dern NDBs one is constantly flying tiny S turns

Anecdotal evidence reveals the New Zealand CAA tolerance in their particular manual for a DME arc, is plus or minus 2.5 nm. That seems reasonable. Yet in flight tests, some Examiners/ ATO's fail a candidate if he is outside plus or minus 1.5 NM which is ridiculous. If true, each Examiner seems to have his own ideas..

The FAA instrument rating standard for a DME arc is plus or minus 1.0 n.m.

Both DME ARC transitions and NDB approaches require a little bit of "Kentucky Windage"