TM 1–1520–238–T–1
3–17
3–3
APU – OPERATING INSTRUCTIONS (cont)
3–3
WARNING
APU operation exceeds acceptable safe
noise levels. Personnel working near or
operating will wear approved ear protection
to protect their hearing. Failure to comply
could result in permanent hearing loss.
CAUTION
Do not attempt to use the 95%/NORM
switch when outside ambient air
temperature is above –18C (0F). The
viscosity of the hydraulic fluid and APU oil
lubricant varies with surrounding climatic
conditions of the region. If the 95%/NORM
switch is used in warm climatic
conditions, extreme mechanical stress is
placed on the utility hydraulic accumulator
shaft. Excessive wear loads are also
placed on the power takeoff (PTO) clutch
during sudden engagement which occurs
during 95%/NORM operation, thus
decreasing the duty life of the dry friction
clutch.
Make sure access door R325 is closed and
secured before initiating APU start–up.
Failure to comply could result in thermal
damage to the aircraft structure.
NOTE
APU START/RUN/OFF switch is a spring
loaded toggle switch which will return to RUN
from START.
APU FAIL indicator on the pilot
caution/warning panel remains lit until APU oil
pressure reaches normal operating APU oil
pressure.
