摘要 |
A pitch control system has a main electronic control, a mechanical back-up control and a switching system for transferring pitch control from the electronic to the mechanical control in the event of electronic control failure. The switching system utilizes a switch for comparing the output of the electronic and mechanical control systems, the switch choosing the mechanical system if a failure occurs in the electronic control system. In certain failure modes, an enable solenoid simultaneously locks out the switch, to ensure mechanical pitch change control, and resets the mechanical back-up control to provide a lower degree of pitch control than conventional back-up controllers.
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