What should the crew check if they notice unusual brake performance?

When the crew experiences unusual brake performance, checking the brake system temperature is crucial. This is because excessive heat can significantly affect braking efficiency and performance. High temperatures in the brake system may indicate problems such as overheating, which can stem from extended brake usage, malfunctioning components, or improper operation. Monitoring temperature allows the crew to assess whether the brakes are functioning within normal parameters or if there is a critical issue that needs immediate attention.

In contrast, while landing gear position, hydraulic fluid levels, and brake system resets could be relevant in certain contexts, they do not directly address the immediate concern of brake performance anomalies. Landing gear position primarily pertains to readiness for takeoff and landing, hydraulic fluid levels relate to the functioning of various hydraulic components, and brake system resets might be pertinent in troubleshooting certain failure modes, but they are not the most immediate checks to determine the state of braking efficiency in response to the noted issue. Thus, assessing brake system temperature directly correlates to understanding and managing the unusual brake performance that has been observed.