How many gearboxes does the AMAD contain?

• A. One
• B. Two
• C. Four
• D. Three

Answer: (B)

AMAD is the centralized drive that powers aircraft accessories by transmitting engine rotation to the gearboxes that run things like generators and hydraulic pumps. In the Growler, this assembly contains two independent gearboxes—the forward (front) accessory gearbox and the rear (aft) accessory gearbox. Having two gearboxes lets each drive its own set of accessories and provides redundancy, so essential systems stay powered even if one path has an issue. That’s why the correct count is two. The arrangement isn’t one because you need separate drives for multiple subsystems, and it isn’t three or four because the standard AMAD layout uses two gearboxes to balance redundancy with simplicity.