Are there no master cautions to advise the crew that the AP is approaching the limit of its control authority? I ask because my (military) type, of 1970s design, had just such a feature. The AP included a low level terrain-following mode and the designers judged it essential to give the pilot some warning of the need to take over heavy control loads lest the aircraft nose-dive straight into the ground upon disconnection. There was also a caution displayed when the HP spool RPMs diverged by more than 15% with autothrottle engaged. Given the severity of the outcomes described above, it would seem that such features might have been invaluable in alerting crews to the crisis about to be unleashed on them. Dumping dangerously out-of-trim forces on the pilot with no prior warning and no fade-out period seems to me very poor system design. Presumably such features are commonplace in contemporary, non-grandfathered designs?
Last edited by Easy Street; 18th Jan 2021 at 18:56.