No vehicle shall be parked on the AOA unless secured against rolling by an engaged handbrake or an equally effective measure. Ignitions shall be switched off unless required for auxiliary functions.

• A. Engaged handbrake or equally effective measure
• B. Ignitions must remain on
• C. Wheel chocks only
• D. No special measures

Answer: (A)

Securing a vehicle on the AOA is about preventing any rolling movement. The proper way is to engage the parking brake and/or use an equally effective method to immobilize the vehicle. This could include devices like wheel chocks or an automatic brake system, as long as they reliably prevent motion. At the same time, the ignition should be off unless you need it for auxiliary functions, to avoid unintended movement or unnecessary engine operation. This combination minimizes the risk to aircraft, personnel, and ground equipment. Leaving the ignition on or relying on insufficient measures would fail to meet the safety requirement, and using a narrower option like wheel chocks only doesn’t capture the full allowance of an equally effective method.