Maybe it's the way the question is worded. When at right angle to the NDB, is the important bit rather than when the NDB is at a right angle to the aeroplane..subtle. I understood it as when the aircraft was 270 from the NDB (a 'radial' if you like) but with a heading of 170 + 4 drift. That does equal 284 on the RBI.
Didn't have any questions on the NDB in my IMC exam. A few on ILS, but most on a route that had to be plotted and plogged exactly as per the Nav exam.
Last edited by GeeWhizz; 21st November 2011 at 22:35.