Airbus ILS course

[salamanderpress]

Thanks a lot, Sabenaboy for a very lucid explanation. You're lucky to have such a good source for information.

And so are we, through you.

[rudderrudderrat]

Hi sabenaboy,

Thanks for the explanation.

The reason why we only check this at 350' can be found in the FCOM PRO-NOR-SRP-01:

Sorry for being a bit dense, but we check the ILS course during the briefing before the approach.
I still don't understand why Airbus requests us to do the check at such a late stage during the approach. The appropriate time to correct any error was before we commenced the approach.

[sabenaboy]

Sorry for being a bit dense, but we check the ILS course during the briefing before the approach.

Of course, we also check that the ils course is correctly inserted during the briefing. We don't recheck it at 350' during a normal ILS app, but only during cat II/III ops.

It's highly unlikely that the inserted ILS course would change after you initially made sure it was correctly inserted. However, it's only after reaching 700' that the ils course + freq are frozen, (+ <400' land mode can only be disengaged by "engaging the go-around mode). Perhaps Mr Airbus wants us to check it at that height, because only then is the ils course + freq definitively locked in the RADNAV page and can't be changed any more. (manually, inadvertently or due to some malfunction) Just guessing here, but that appears to be a plausible explanation.