What type of brake system does the Cessna 172 use?

The Cessna 172 utilizes a hydraulic disc brake system, which is the correct answer. Hydraulic disc brakes are favored in aviation for their reliable performance and effective stopping power. This system operates by using hydraulic fluid to transfer force from the pilot's foot on the brake pedals to the brake calipers, which press the brake pads against the discs mounted on the wheel hubs.

The design of hydraulic disc brakes provides advantages such as better heat dissipation compared to drum brakes, reduced brake fade, and consistent modulation of braking force. This is especially important in situations where precise control is necessary, such as during landing or when taxiing on the runway.

The other types of brake systems mentioned are not applicable to the Cessna 172. Pneumatic brake systems rely on compressed air which is not standard in light aircraft like the Cessna 172. Mechanical drum brakes are older technology that involve a more complicated setup with less efficient braking performance compared to disc brakes. Electromechanical brakes are typically utilized in newer advanced aircraft designs and are not present in the Cessna 172, which has retained a more traditional hydraulic system for reliability and ease of maintenance.