PRESSURIZED AIR SYSTEM MAINTENANCE OPERATIONAL CHECK (cont)
If referenced out of one paragraph or volume into another for additional
troubleshooting, upon completion of the task, return to the maintenance
operational check for the original paragraph or volume.
Make sure all helicopter safing procedures are accomplished. Observe all
safety precautions during troubleshooting and maintenance operations.
Failure to do so could result in death or serious injury. If injury occurs, get
medical aid immediately.
1. Check to ensure that bleed air shutoff valve indicator is in the CLOSED position. If valve indicator is in
OPEN position (fig. 751), replace bleed air shutoff valve (TM 1-1520-238-23).
Bleed Air Shutoff Valve Indicator
3. Perform visual check of pressurized air system, main transmission, and APU. If any damage or leakage is
found, repair leaking/damaged component. If air flow is present at SDC overboard exhaust, replace SDC
check valve (TM 1-1520-238-23).
4. Remove external power application pressurized air (TM 1-1520-238-23).
5. Check to ensure that bleed air shutoff valve indicator is in the CLOSED position. If valve indicator is in
OPEN position, replace bleed air shutoff valve (TM 1-1520-238-23).