On the ground, the Automatic Brake System can be armed only in the Rejected Takeoff Mode. In order for the RTO mode to be engaged, the following conditions must be met: 

- Aircraft on ground

- Both throttles are at idle

If RTO is selected with the aircraft on the ground with the throttles not at idle, the FAULT light will illuminate. The FAULT light can be extinguished by moving the Autobrake switch to OFF. RTO mode can then be engaged by retarding the throttles to idle, and moving the switch to RTO.