Max Time for ATC S/by Gen to Kick in?
For Airfield ATC guys and gals. In the context of continuity of the Ils signal, is there a max time stipulated (and where) for the s/by genny to kick in, in the event of a mains failure to ATC.
The reason for the query is that the A320 family 'remembers' the signal for 7 secs before throwing in the towel - unless below 200' RA in which case it throws the towel in immediately! I have it in the back of my mind that somewhere it stipulates that the Atc S/b genny should be in within 5 secs.
I would be grateful for 'chapter and verse'.
Many thanks and cheers,
mcdhu