What is a probable cause of excessive travel in brake pedals reported by a pilot?

Excessive travel in brake pedals can often occur when there is a lack of fluid in the brake system. When the fluid level is low, it results in insufficient hydraulic pressure, which prevents the brakes from engaging fully. As the pilot presses the brake pedal, there is a delay or increased travel before any significant braking effect is felt. This happens because the fluid must first fill any gaps or air pockets in the system before pressure builds adequately to engage the brakes effectively.

Given this understanding, it's crucial to maintain the appropriate fluid level in the brake system to ensure proper brake function and responsiveness. The other choices would lead to different symptoms: worn brake pads would generally manifest as decreased braking efficiency rather than excessive pedal travel, excessive fluid might cause other issues but wouldn't typically lead to excessive travel, and improper pedal adjustment could affect how the pedal feels but isn't directly linked to fluid levels. This highlights the importance of regular maintenance checks, which include monitoring brake fluid levels to ensure safe and effective braking performance.