When can RTO be disarmed?

Disarming the RTO (Rejected Takeoff) function is specifically related to the aircraft’s operational modes during critical phases of flight. It can be disarmed when the thrust is reduced to below idle. This is because the RTO function is primarily designed to activate if an immediate stop is required during the takeoff roll, and reducing thrust below idle indicates a decision to cease forward motion.

When thrust is below idle, the aircraft is no longer accelerating, which effectively means it is safe to disarm the RTO function as it is no longer relevant to the current operation. The RTO feature becomes inactive if the pilots determine that the takeoff is not continuing, thus the risk of needing to execute a rejected takeoff diminishes substantially at that point.

In contrast, the other scenarios—such as being weight on wheels (WOW) on the ground, any pedal position, or a fault being present—would either indicate situations where disarming the RTO may not be advisable or relevant. For example, the WOW condition indicates that the aircraft is on the ground, which could lead to confusion about the operation of the RTO system, but it does not inherently mean the RTO should be disarmed immediately.