How should you respond if the ammeter shows a full positive deflection?

A full positive deflection on the ammeter indicates an excessive electrical output from the alternator, which can harm the aircraft's electrical systems. This condition suggests that the alternator is overcharging the battery, potentially leading to battery damage, overheating, or even failure of electrical components due to excessive voltage.

To address this situation, switching off the alternator and nonessential electrical equipment is the appropriate response. By doing this, you reduce the electrical load and prevent further damage while maintaining sufficient electrical power for essential systems. This step helps protect the integrity of the aircraft's electrical system.

The other responses do not effectively mitigate the issue at hand. Increasing the throttle could exacerbate the electrical overloading. Landing immediately might not be necessary or safe unless there are additional alarming symptoms, and turning on all electrical systems would further increase the load and potentially worsen the situation.