When is a [BOOST PUMP] annunciator activated?

The [BOOST PUMP] annunciator is activated whenever the starter is activated or manually switched ON. This behavior is designed to ensure that the fuel system is adequately supplied with fuel pressure during critical phases of engine start-up and operation. When the starter is engaged, the boost pump enhances fuel pressure to prevent engine stall or failure due to insufficient fuel flow, making sure that the engine receives the necessary amount of fuel for optimal performance.

The activation during engine start and the manual switch ON contributes to maintaining safety and reliability throughout the operation of the aircraft. In situations where the fuel system is under stress, such as during start-up or system checks, this early activation is crucial for preventing issues that could arise if the fuel supply was inadequate.