What happens when the BAT 1 switch is turned on during ground operations?

When the BAT 1 switch is turned on during ground operations, the battery-powered blower activates. This is an essential function for the aircraft’s electrical systems because it helps to ensure proper airflow in the cockpit and to maintain comfortable conditions for the crew. It also plays a role in cooling the avionics systems, which is vital during ground operations when the engines may not be running.

The activation of the battery-powered blower is particularly important because, on the ground, the aircraft might not have external power or engine operation to provide ventilation. Therefore, this function supports both crew comfort and the performance of critical systems until the engines or an external power source can take over.

In contrast, when the BAT 1 switch is turned on, it does not automatically activate cockpit lights or start the APU. Cockpit lighting typically requires additional switches to be activated. Similarly, the APU must be started manually unless configured to do so automatically, which is not the case with BAT 1 activation alone. Additionally, turning on the battery switch does not cause all electrical systems to go offline; the opposite is usually true as it powers certain essential systems.