When the EHYD PX LO annunciator illuminates, it indicates that emergency accumulator hydraulic pressure is below which threshold?

The EHYD PX LO annunciator is designed to alert the pilot when the pressure in the emergency hydraulic accumulator falls below a critical threshold that could compromise the system's functionality in emergency situations. The correct threshold value at which this warning illuminates is 2400 psi, with a tolerance of plus or minus 150 psi.

This is important because the emergency hydraulic system is crucial for operating essential flight controls in case of a primary hydraulic system failure. Maintaining pressure above 2400 psi ensures that there is enough hydraulic fluid pressure available to facilitate the operation of vital systems such as the landing gear, flaps, and other control surfaces.

Understanding the importance of this threshold allows pilots to respond appropriately by checking hydraulic systems and being prepared to take necessary actions to maintain control of the aircraft should this warning illuminate.