Final answer:
It is false that technicians should always drain the air system before driving the truck; they should ensure it is properly pressurized, moisture-free, and maintained instead, only draining as part of routine maintenance.
Step-by-step explanation:
The statement that technicians should always drain the air system before driving the truck is false. Instead, it is vital to ensure the air system is properly pressurized and free of water or contaminants, which means periodically draining the air tanks to remove moisture and prevent system failure, but not necessarily before each drive. Technicians must ensure that the air brake system is properly maintained, and part of that maintenance may include bleeding the air out of the brake lines to prevent compression of any gas within the system, which can affect the efficiency of the brakes.
It is crucial that the air brake system is working optimally for safe operation, and thus performing regular maintenance and checks is part of a technician's responsibilities. However, fully draining the system before each trip could lead to unnecessary downtime and potential operational issues if not properly re-pressurized.