Table 4-1. Troubleshooting (Continued)
Main rotor does not
Binding of gearbox.
c. Replace engine. (Refer to
Dirt or sand between
a. Blow out with compressed air.
rotate by 30% N1.
fourth stage turbine
wheel and shroud.
b. Turbine blade tip (N2)
b. Shutdown. Repeat start
procedure. If not rotating after third
attempt, replace engine. (Refer to
c. Carbon formation
c. Shutdown. Ensure that the oil
being used is MIL-L-7808F or G, or
MIL-L-23699. Repeat start procedure.
If not rotating after third attempt,
replace engine. (Refer to
Unable to obtain
maximum N2 rpm.
cracked or broken at
governor and gas
producer fuel control
Power loss, N2 droop
a. Air leak in control air
b. Improper control
c. Faulty power turbine
d. Fuel obstruction,
Corrosion buildup on
shaft causing a tight fit
in the throttle shaft
a. Improper rigging.
Tighten tube fittings.
Replace governor. (Refer to para
d. Inspect, flush and/or replace fuel
lines in system. (Refer to Chapter 5.)
Check the engine for possible
vibration causes. (Refer to the
vibration inspections in para 12-8.)
Apply (Item 36, Table 2-2) to the
area shown in figure 4-3 and figure
4-4; a one second spray should be
sufficient. Rotate shaft, back and
forth, following spray to assure
penetration. Repeat spray if
Refer to para 4-3.
b. Cracks, scratches, and
c. Improper sealing or