TM 1-1520-238-T-4
6–164
Change 5
6–81.
DRIVE SYSTEM – VIBRATION MAINTENANCE OPERATIONAL CHECK (cont)
6–81
Task
Result
To avoid engine damage, do not operate engine steady–state between
24%–38% Np or in the 57%–72% Np range.
CAUTION
e. Advance ENG 1 PWR lever to a position
where both engine torques are matched at
101% Np. Continue advancing until ENG 1
torque is approximately 10% greater than
ENG 2 and an increase in ENG 1 Np is
noted.
f. Slowly advance ENG 1 PWR lever above
101% Np until HIGH RPM ROTOR indicator
is lighted.
(ACV) If pilot HIGH RPM ROTOR indicator does
not light at 104% Nr, go to paragraph 6–85.
(ACW) If pilot HIGH RPM ROTOR indicator does
not light at 108% Nr, go to paragraph 6–85.1.
(ACW) If CPG HIGH RPM ROTOR indicator does
not light at 108% Nr, go to paragraph 6–85.2.
(ACV) If CPG HIGH RPM ROTOR indicator does
not light at 104% Nr, go to paragraph 6–86.
g. Set ENG 1 PWR lever to IDLE. Verify NG is
at idle speed.
h. Set ENG 1 PWR lever to FLY. Verify ECU is
reset.
i. Raise collective to 20% torque. Note any
rotor instability or unusual control
positioning.
j. Check VIB GRBX indicator on pilot and
CPG caution/warning panels
(figs. 6–17 and 6–18).
If VIB GRBX indicators light, go to paragraph 6–87.
2. Shut down helicopter (TM 1-1520-238-CL).
END OF TASK
