From the 800 FCOM
Ground Operation
During landing, the auto speed brake system operates when these conditions occur:
• SPEED BRAKE lever is in the ARMED position
• SPEED BRAKE ARMED light is illuminated
• radio altitude is less than 10 feet
• landing gear strut compresses on touchdown
Note: Compression of any landing gear strut enables the flight spoilers to deploy. Compression of the right main landing gear strut enables the ground spoilers to deploy.
• both thrust levers are retarded to IDLE
• main landing gear wheels spin up (more than 60 kts).
The SPEED BRAKE lever automatically moves to the UP position and the spoilers deploy.
If a wheel spin-up signal is not detected, when the air/ground system senses ground mode (any gear strut compresses) the SPEED BRAKE lever moves to the UP position and flight spoiler panels deploy automatically. When the right main landing gear strut compresses, a mechanical linkage opens the ground spoiler bypass valve and the ground spoilers deploy.
If the SPEED BRAKE lever is in the DOWN position during landing or rejected takeoff, the auto speed brake system operates when these conditions occur:
• main landing gear wheels spin up (more than 60 kts)
• both thrust levers are retarded to IDLE
• reverse thrust levers are positioned for reverse thrust.
The SPEED BRAKE lever automatically moves to the UP position and spoilers deploy.
After an RTO or landing, if either thrust lever is advanced, the SPEED BRAKE lever automatically moves to the DOWN detent and all spoiler panels retract. The spoiler panels may also be retracted by manually moving the SPEED BRAKE lever to the DOWN detent.