737 Anti Ice/CAT1
Quick question, we had a faulty cowl valve on the engine TAI, the engineers manually locked it on but it made the aircraft Cat1. Just wondering why the MEL/PDG restricted the aircraft to CAT1? I think there was something about a high stage valve being locked out as part of the rectification for the cowl valve.
Also as regards CAT1, our SOPs call for Gear down/F15 at glideslope alive on a CAT3 approach, however our normal approach would be low drag and gear down at 4-5nm. I've heard various reasons, but is there a technical reason why you cant do a low drag approach in a coupled CAT3?
Many thanks