Turn coupling nut 1 flat for 60° wrench arc.
(d) Turn coupling nut 2 flats for 120° wrench arc.
(4) Tightening to 30° wrench arc.
(a) Snug the nut.
(b) Place an open-end wrench on nut.
Note position of wrench handle. (Pick out point of reference on engine in line with handle.)
(d) Invert wrench using the same nut flats. The angular difference between the centerlines of the
wrenches in the two positions is 30°.
Turn wrench to position established in step (c).
ENGINE POWER LOSS, N2 DROOP OR FLAMEOUT.
Check maintenance procedures for OH-58 aircraft when a power loss, N2 droop, or flameout occurs.
may occur during a normal flight maneuver requiring a rapid increase in power (i.e., rapid collective and/or tail
rotor inputs, high G turn, steep turn). If N2 droop occurs, but low RPM warning is not activated and N2 recovers
to 103 percent on OH-58A aircraft, and further N2 droop is not experienced, no maintenance action is required.
For all maintenance actions noted
below, pneumatic line fittings are to
be torqued to specified values utiliz-
ing a torque wrench. All lines are to
be installed so that there is no
preload or deformation of the line in
accordance with applicable TMs.
When a power loss, N2 droop, or flameout occurs (in parameters other than those established in para-
graph above), check/inspect to determine the reason/reasons in accordance with the troubleshooting charts in
TM 55-2840-231-23 for OH-58A/-700 engine.
If the reason/reasons for power degradation cannot be established using the procedures specified in para-
graph above, request assistance horn AVIM maintenance and proceed with the maintenance actions noted in
paragraphs (1) through (4) below. If this is a
recurrence of power degradation on this aircraft/engine and the
maintenance actions listed below have been complied within the last 100 flying hours, replace the engine.
(1) Recheck engine throttle controls for proper rigging. Check the throttle angle on the fuel control at
the idle detent for the pilots and copilots twist grip and physical contact with minimum and maximum stops.
Maximum allowable variation between the pilots and copilots twist grip is 5/64 inch as measured on the fuel
control sector at idle. Re-rig controls if not within specifications in accordance with TM 55-1520-228-23 and
TM 55-2840-231-23 for OH-58A aircraft.
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