Folks, I'm trying to understand the procedure for flying a backcourse departure in a 747-400 and wondering if it's possible to simulate the ND/PFD backcourse presentation on the ground (at the gate).
I have read in my engineering training notes that the backcourse logic in the EIU's reverses the LOC signal and removes the G/S pointer
and scale. On previous occasions, at the gate, I have entered an ILS course on the Nav Rad page which was greater than 90deg to the airplane heading/track and this resulted in the the G/S pointer being removed, but not the scale (I'm not entirely sure that this phenomenon is backcourse related).
Questions:
1) Are most loc antennae capable of producing signals on the reverse side (whether reliable or not is a different question).
2) During backcourse flying procedures, what crs is entered on the Nav Rad page (the normal front crs for that frequency?)?
3) Do you think it would be possible to generate backcourse conditions at the gate when all the gates at my local airport are on the front side of the loc antennae. i.e. how do the EIU's know that you are on the front or backside of the antennae? (I assume this logic works without FMC ILS database knowledge or IRU/GPS position). Is aircraft heading/track factored into the equation or does, perhaps, the lateral movement of the aircraft and subsequent increase/decrease in sensed depth of modulation cause the backcourse indications to appear
Thanks for any insight.
Regards.
NSEU