What does pulling the LDG Gear circuit breaker during the EMER GEAR EXTENSION checklist accomplish?

Pulling the LDG Gear circuit breaker during the EMER GEAR EXTENSION checklist removes electrical power from the landing gear system. This action is essential because, in an emergency situation, it ensures that the gear system can be operated manually and independently from the electrical system that may have failed. By cutting off the electrical power, the potential for inadvertent retraction of the gear is eliminated, allowing for a controlled manual extension of the landing gear. This ensures that pilots can safely deploy the landing gear even if other systems are compromised.

The other choices do not accurately reflect the purpose of pulling the circuit breaker. Activating the landing gear or initiating a sequencing process would involve restoring power to the system rather than removing it, which would not be appropriate in an emergency context. Depressing the landing gear handle does not directly relate to the action of pulling the circuit breaker, as this action is concerned with ensuring a safe manual gear extension procedure.