Did you mean AP 3456, The Royal Air Force Manual of Flying? If you go to
http://www.centralflyingschool.org.uk/Today/3456.htm , all is revealed. It will, of course, cost you if you want to buy it. If you have access to the MoD Intranet, you can view it free at (UNCLAS),
http://www.ap3456.dii.r.mil.uk/ .