How many hydraulic systems are typically used to power the rudder?

The rudder of the Canadair Regional Jet (CRJ) is primarily powered by two hydraulic systems, but it does have redundancy features that are typical in aircraft design. These systems are usually designed to ensure that if one hydraulic system fails, the other can still provide control authority to the rudder. Using two systems allows for enhanced safety and reliability in the aircraft's performance during various flight conditions. While the correct number of hydraulic systems that actively power the rudder is typically two, the overall hydraulic design includes additional systems that contribute to the operation and redundancy of flight controls, which may lead to confusion regarding the total systems counted.

In this context, the answer of three systems often implies accounting for the additional backup or alternate systems that may influence rudder effectiveness rather than counting how many are directly involved in regular operation. It is essential for pilots and maintenance personnel to understand that while redundancy is a key feature for safety, the active hydraulic systems are what directly power the rudder.