What indicates brake failure in an aircraft?

The indication of brake failure in an aircraft is best interpreted through the presence of warning lights flashing in the cockpit. Warning lights are specifically designed to alert pilots and ground crews to various malfunctioning systems, including the braking system. When a brake failure occurs, the corresponding warning lights illuminate, notifying the crew to take immediate corrective actions.

Flashing warning lights typically trigger a series of checks and responses from the crew to ensure safety and make informed decisions regarding the aircraft's operation. This is vital for maintaining safety during taxi, takeoff, and landing operations.

In contrast to this, while excessive wear on tires can hint at issues related to braking, it is not a direct or immediate indication of brake failure; rather, it is a consequence of prolonged use or inadequate maintenance. Reduced fuel efficiency does not provide any immediate insight into the brake system status and is unrelated to brake functionality. The concept that "everything that can come out will" does not specifically address the issue at hand and lacks the precision required to indicate brake failure. Therefore, the presence of flashing warning lights stands out as the clear and accurate indicator of brake failure in an aircraft.