Tail Rotor Gearbox. The tail rotor gearbox is lo-
cated on the extreme aft end of the tail boom--in some
cases on top of the tailboom vertical fin (Figure(3-3.I).
The gearbox is splashlubricated. It consists of mating
input and output gear assemblies set into a case pro-
vided with a vented oil filler cap, oil level sight gage, and
a drain plug with a magnetic insert plug for collecting
metal particles. By analyzing these metal particles, the
condition of the gearbox gears and bearings can be de-
termined. Flexible couplings are provided for attaching
the tail rotor drive shaft onto the input end of the gearbox.
The tail rotor gearbox provides a specific degree change
in tail rotor drive shaft direction and a specific speed
reduction between input shaft and output shaft on which
the tail rotor assembly is mounted.
When troubleshooting or working on a specif-
ic single--rotor power train system or compo-
nent, always refer to the applicable mainte-