How long must the manual parking brake release button be pressed to release pressure?

The requirement to hold the manual parking brake release button for a duration of 30 seconds is based on the operational specifications of the F-35 aircraft systems. This 30-second time frame ensures that all necessary hydraulic pressure within the parking brake system is adequately released, allowing for safe and effective disengagement of the brake system.

During this period, pressing the release button continuously helps to confirm the release action and allows the system to fully respond, ensuring that the brakes are disengaged before the aircraft is moved. This is critical for operational safety, as premature release may not fully unlock the system, potentially leading to a hazardous situation if the aircraft is inadvertently rolled.

While the other time options suggest varying durations, they do not align with the established protocol for the manual brake release, which emphasizes the necessity of a full 30 seconds to guarantee proper operation. Overall, adhering to this guideline is essential for both crew safety and the integrity of the aircraft systems.