TM 1-1520-238-T-4
6–162
Change 4
6–81.
DRIVE SYSTEM – VIBRATION MAINTENANCE OPERATIONAL CHECK
6–81
Tools:
Nomenclature
Part Number
Tool Kit, Powertrain
SC518099CLA013
Repairer’s
Personnel Required:
68D
Aircraft Powertrain Repairer/NDI
152FG
Maintenance Test Pilot
References:
TM 1-1520-238-T-6
TM 1-1520-238-CL
TM 1-1520-238-23
Equipment Conditions:
Ref
Condition
Paragraph 6–12
DRIVE SYSTEM –
INDICATORS
MAINTENANCE
OPERATIONAL
CHECK
completed
WARNING
Make sure that helicopter safing procedures are accomplished. Observe all
safety precautions during troubleshooting and maintenance procedures.
Failure to do so could result in death or serious injury.
NOTE
Refer to pilot station (fig. 6–12) and CPG station (fig. 6–13) for cockpit
configuration and equipment.
If referenced out of one paragraph or volume and into another for
additional troubleshooting, upon completion of the task return to the
maintenance operational check for the original paragraph or volume.
1. Complete the maintenance operational check as follows:
Task
Result
a. Start and run helicopter
(TM 1-1520-238-CL). On pilot master
caution/warning panel (fig. 6–17), check that
LOW RPM ROTOR indicator goes out when
Nr RPM% on pilot ENG–RTR RPM%
indicator (fig. 6–22) reaches or is above
93%.
If main rotor or tail rotor do not rotate, refer to
TM 1-1520-238-23 to visually inspect drive system.
If LOW RPM ROTOR indicator remains lighted above
93% Nr on pilot and CPG master caution/warning
panels, go to paragraph 6–82.
b. Increase power on one engine to 100%, and
then retard throttle slowly until Np vertical
scale reads 80% to 85% Np.
