FAA Aircraft Dispatcher Practice Exam

How many hydraulic systems does the B727 have?

1. One

2. Two

3. Three

4. Four

The correct answer is: Three

The Boeing 727 is equipped with three hydraulic systems, which are designated as the left, right, and center systems. Each hydraulic system plays a critical role in supporting various components of the aircraft, such as controlling the flight control surfaces, landing gear, and brakes. Having three independent hydraulic systems enhances the safety and reliability of the aircraft, allowing it to continue operating even if one of the systems were to fail. Each system has its own independent reservoir and pump, which ensures redundancy and maintains functionality across various flight conditions. The decision to implement three hydraulic systems is a design feature aimed at improving controllability and system integrity, which is particularly important for a commercial aircraft operating in diverse environments and handling scenarios. This configuration is common in many aircraft designs to provide necessary power and backup systems for critical flight functions.