When should you turn on the ignition switches?

The ignition switches should be turned on when engine anti-ice is on because this condition necessitates additional engine monitoring and ensures consistent engine performance in environments where ice formation could occur. When anti-ice is activated, it can affect the combustion process, and keeping the ignition systems engaged provides an added layer of safety by ensuring that, in the event of any irregularities in engine operation, the ignition system can respond promptly.

Turning on ignition switches during this condition helps maintain engine reliability and performance, particularly in colder temperatures where ice accumulation could impact efficiency or lead to engine failure. This proactive approach is part of best practices in flight operations to mitigate risks associated with icing and to ensure that any deviations from normal operation can be addressed swiftly.