Which flight control law applies in mechanical backup conditions?

In mechanical backup conditions, the flight control system of the aircraft reverts to a mode designed to maintain aircraft control using direct, manual inputs from the pilot. Mechanical backup is a situation where the electronic control systems fail or are not available, and the pilot must operate the aircraft using purely mechanical linkages. This condition ensures that basic flight control can still be maintained, albeit with limited functionality compared to the normal or alternate flight control laws.

Other options refer to various modes of operation within the aircraft's electronic flight control system. Normal law provides the full suite of protections and optimized performance characteristics. Alternate law offers reduced protections and some limitations but is still reliant on electronic systems. Direct law removes all protections and allows immediate pilot inputs directly to the control surfaces without the mediating electronic systems. In contrast, mechanical backup indicates a complete transformation to a situation where traditional electronic systems are inoperative, making it the most applicable choice in this context.