What is installed at the hydraulic maintenance panel when the electric pump is inoperative?

When the electric pump is inoperative, a hand pump is installed at the hydraulic maintenance panel to allow for manual operation of the hydraulic systems. This provides a critical backup method for maintaining hydraulic pressure and ensuring that the essential systems continue to operate, especially in scenarios where power-driven systems might fail.

Hand pumps allow ground crews to manually pressurize the hydraulic system for testing, servicing, or emergency conditions without relying on electrical power. This capability is vital in maintaining operational readiness, as it ensures that the aircraft can still be serviced safely even if the primary electric systems are unavailable.

While options related to backup electric pumps, pressure gauges, or flow controllers play roles in hydraulic system performance and monitoring, they do not serve the same function as the hand pump in providing an alternative means of hydraulic power when the electric pump fails.