Final answer:
True. Chocks are used to secure the left side wheel of a belt loader when parked at an aircraft.
Step-by-step explanation:
When parked at an aircraft, a belt loader must have the left side wheel secured by chocks both in front of and behind the wheel. This statement is true.
Belt loaders are used at airports to load and unload cargo from aircraft. To ensure the safety and stability of the belt loader while it is parked, chocks are placed in front of and behind the left side wheel. These chocks prevent the wheel from moving and help prevent the belt loader from rolling or tipping over.
By securing the left side wheel with chocks, the belt loader remains stationary, allowing for safe and efficient loading and unloading operations.