Keeping your Lakota helicopter’s emergency power supply (EPS) charged depends on you performing the proper tests.
The EPS provides 30 minutes of power to the emergency exit lighting and the standby horizon if there’s a complete electrical failure. It’s powered by the PS-835 battery on the right-hand side of the aircraft behind the sound proofing panel.
Test the emergency power supply using the BAT HOR/EXIT test during pre-start checks. When you move the BAT HOR switch to the TEST position, you should see the EMER BAT LED turn green on the overhead panel, the HOR BAT lights up on the CAD, and the EXIT panels illuminate. That means the power supply is working properly.
But if the LED changes from green to red, or turns red immediately during the test, the battery isn’t sufficiently charged. Make sure you document the problem in the aircraft notebook so maintainers can troubleshoot the system according to aviation maintenance manual AMM 34-24-00, 1-1.
The emergency battery is recharged by the external power unit (EPU) or the aircraft generators. You must make sure the EM/EX switch is in the ARM position to charge the battery while in flight.
To keep the emergency battery from draining and to prolong its life, make sure both the STBY HOR and EM/EX are turned off
at the end of the flight before you leave the aircraft.