In what situation does ACMP 1/2 turn on automatically in flight?

ACMP 1 and ACMP 2 are the electrical hydraulic pump systems in the Embraer Regional Jet (ERJ), responsible for providing hydraulic pressure to various aircraft systems. In-flight, these pumps can be activated automatically based on specific conditions to ensure that there is sufficient hydraulic power available for critical systems.

The automatic activation occurs when there is engine failure or when the flaps are positioned greater than 0. This is crucial because, in the event of an engine failure, the hydraulic system associated with that engine may also lose pressure, necessitating the need for an alternative hydraulic pressure source. Similarly, when the flaps are extended, hydraulic pressure is required to control the flaps' position and ensure proper aerodynamic control of the aircraft. Therefore, the design of the ERJ systems ensures that ACMP 1 or 2 activates automatically under these specific circumstances to provide the required hydraulic support, enhancing the safety and controllability of the aircraft.

This function is essential to maintain control surfaces' operation and other hydraulic-dependent systems when conditions change during flight, ensuring the aircraft's performance remains stable.