Parker Aerospace developed and certified an alternate flight control unit (AFCU) that allows for full independent control using dedicated flight deck sensors and the existing hydraulic actuators on the control surfaces.
With certification agencies demanding greater independence between primary flight controls and standby or backup systems, a robust response is to incorporate an independent flight controller that will allow continued safe flight and landing. This Parker AFCU contains the simplified direct mode control laws similar to what is provided in the primary system and provides servo-loop control and engagement logic for controlling every axis.
With the AFCU, all other electronic units used in the primary system can be bypassed with continued safe flight and landing being maintained. Protection against inadvertent engagement is assured and monitoring is routinely and independently performed by the primary flight control computer.
The AFCU is designed for simplicity and includes a power supply (including for the dedicated flight deck sensors), feedback demodulation, application of the simplified control laws, servo loop control, and engagement signals to one actuator on each primary control surface. The associated actuators include a dual coil electro-hydraulic servo valve, a dual LDVT main ram position sensor, and a dual coil shutoff valve.

Parker Aerospace developed and certified an alternate flight control unit (AFCU) that allows for full independent control using dedicated flight deck sensors and the existing hydraulic actuators on the control surfaces.
With certification agencies demanding greater independence between primary flight controls and standby or backup systems, a robust response is to incorporate an independent flight controller that will allow continued safe flight and landing. This Parker AFCU contains the simplified direct mode control laws similar to what is provided in the primary system and provides servo-loop control and engagement logic for controlling every axis.
With the AFCU, all other electronic units used in the primary system can be bypassed with continued safe flight and landing being maintained. Protection against inadvertent engagement is assured and monitoring is routinely and independently performed by the primary flight control computer.
The AFCU is designed for simplicity and includes a power supply (including for the dedicated flight deck sensors), feedback demodulation, application of the simplified control laws, servo loop control, and engagement signals to one actuator on each primary control surface. The associated actuators include a dual coil electro-hydraulic servo valve, a dual LDVT main ram position sensor, and a dual coil shutoff valve.