What is one part of the declared distances?

The declared distances for a runway are critical measurements that indicate how much of the runway is available for different phases of flight operations. TORA, or Takeoff Run Available, is one of these declared distances. It specifically represents the length of the runway available for the ground run of an airplane takeoff. This measurement is crucial for pilots when determining the distance required for takeoff under various weight, load, and environmental conditions.

Understanding TORA helps pilots ensure they can safely complete the takeoff without risk of running off the runway. This concept plays a significant role in flight planning and compliance with regulations regarding takeoff performance. The other options listed do not represent specific measurements related to runway operations in the same way that TORA does.