Pilots are only allowed to use ACLS after they have gone through a deployment typically and have over 100 traps. The reason for this is that ACLS can be tricky at times and requires some experience to use the system safely. It can kick off at very inopportune times, and the pilot must be able to take over immediately. In the jet, while flying ACLS you feel the throttles move, but the stick remains stationary which can be a very weird thing at first. Also, when flying ACLS, the pilot has to call "auto" on the ball call so the LSO is aware. As far as landing grades go (a huge part of a carrier pilot's life) ACLS landings aren't graded, so a pilot who can shoot an ACLS landing normally doesn't unless he's very tired after an unusually long flight because you're always trying to keep your GPA up, and ACLS landing grades don't affect it. As far as T-45 training goes, you learn to fly the jet with the HUD, sometimes an instructor will tell you to shut it off for a landing here and there. You don't learn to fly it with the HUD off at first. Flying on standby instruments in the Hornet is pretty awful as they are located right above your right knee. It's very difficult to have a good inside/outside scan when you're looking to your knee and then outside. Also the deck divot thing that was mentioned above was an issue with the ACLS system in the past, so there's actually an algorithm built into the system so jets touch down on a slightly different point every time to mitigate that.