In a power brake failure, the pilot will break the safety wire and remove the guard clip on the emer brake handle, then pull that handle. Approximately how many applications are available with a full system?

In a power brake failure, the pilot will break the safety wire and remove the guard clip on the emer brake handle, then pull that handle. Approximately how many applications are available with a full system?

• A. Five
• B. Nine
• C. Three
• D. Seven

Answer: (D)

A backup emergency brake system provides a limited amount of braking energy stored for use when the primary power brakes aren’t available. Each pull of the emergency brake uses a portion of that stored energy, so the handle can be actuated only a finite number of times. With a full system, the energy reserve is designed to deliver approximately seven brake applications, giving you enough braking force to arrange a safe stop or control while taxiing or landing in a power brake failure situation. The count is approximate because actual performance can vary with factors like temperature, brake wear, and system losses, but seven is the designed average. The other numbers would either undercut the needed braking margin or exceed what the reserve energy is intended to provide.

A backup emergency brake system provides a limited amount of braking energy stored for use when the primary power brakes aren’t available. Each pull of the emergency brake uses a portion of that stored energy, so the handle can be actuated only a finite number of times. With a full system, the energy reserve is designed to deliver approximately seven brake applications, giving you enough braking force to arrange a safe stop or control while taxiing or landing in a power brake failure situation. The count is approximate because actual performance can vary with factors like temperature, brake wear, and system losses, but seven is the designed average. The other numbers would either undercut the needed braking margin or exceed what the reserve energy is intended to provide.