Check work area for tools and parts after completion of maintenance and inspection
Item and Procedure
Perform helicopter safety procedures before starting APU or applying external power.
If the APU is not used for the power on procedural checks, pressurized air and electrical power must be
applied to the helicopter to complete the nitrogen inerting unit operational check.
Start helicopter APU (TM 1-1520-238-23)
(GEN 1 and GEN 2 lights extinguish GEN switch to GEN)
Verify UTIL ACC, PRI, and UTIL HYD pressure levels
Apply external power (if APU not used) (TM 1-1520-238-23)
AFT ELECTRONICS EQUIPMENT BAY (POWER ON)
OPEN ELECTRONICS EQUIPMENT ACCESS DOOR R295
NITROGEN INERTING MONITOR FOR BLACK AND WHITE (FAIL) DISK
PRESS NITROGEN INERT MONITOR PRESS-TO-TEST
Press-to-test simulates a fault in the nitrogen inerting unit. A fault with the NIU is indicated by the black
and white nitrogen inert monitor indicator.
RESET NITROGEN INERT MONITOR INDICATOR BY MANUALLY ROTATING THE KNURLED RING
CLOCKWISE 90 DEGREES AND RELEASE