Couldn't imagine the Queen being allowed, by senior officers, in any aircraft where the DECU fault codes had to be checked (by the Loadmaster, looking behind a little panel in the cabin wall) every 15 minutes, in case everything was about to go pear shaped
The DECU Display is not active in flight unless the ECLs are moved past a 5 degree gate; therefore, the crewman cannot check it every 15 minutes.