ORB abbreviations

I came across an order to use Aldis signals in place of pyrotechnic signals on air to air ranges. The reference given was A.M.C.O. A.10/1941. What did AMCO stand for in 1941? I am assuming it wasn't Air Maintenance Control Office at that time, or was it?

Thanks, confidential makes sense, I think. I had, like Mike O poste assumed that AM was Air Ministry and that O could be order but was stuck on the "C" word. However, having been caught before on assuming I was quite prepared for AM to be something else!

Air Ministry Confidential Order it is.

Afterthought:
What is the name of non-confidential orders? It's like the new term "Human Resources" it implies there is another type of resource - inhuman or alien maybe

I followed the rafcommands link mawganmad posted and it led me to the AIR 72 series at TNA. So if I delved into AIR 72/25 I would probably find the relevant order. The next question is why am I following up by looking at the original order when I know what it says? Answer - not sure but I suspect there may be more of interest in the actual order.

There is an index to the order from 1918 - 1946 in AIR 72/90 but that assumes you know what to look fro and that it is indexed the same way as my thought process. As I failed to find AIR 72 in TNA due to a too specific search string I assume I will miss a lot of interest to me.

see my part one UXB East which you proof read!