temperature, immediately abort the start by depressing
the switches and switchlight unit a second time.
3-9. Hydraulic Start Procedures.
Ear protection must be worn by
control cab when the engine Is being
operated. Failure to observe this
warning will result in damage to and
eventual loss of hearing.
Accomplish the start of a gas turbine engine
(equipped with a hydraulic starter) in accordance with
a. For starting a T55 engine, position the relief valve
selector switch (13, figure 1-8) to the down position. For
starting a T73 engine, position the switch to the up
position. Prior to starting, ensure that the switch is in
the appropriate position.
b. Position and hold the spring-loaded START/RUN
switch (4, figure 1-26) in START until the gasoline
engine starts, then position the switch to RUN. This
action will start the gasoline engine in the hydraulic start
system (figure 1-8). Allow at least a two-minute warmup
prior to energizing the hydraulic starter on the engine
under test, then adjust the engine speed using the HYD
STARTER ENGINE SPEED switch (5, figure 1-26).
c. Note the pressure buildup on the supply pressure
gage (11, figure 1-8). During the foregoing action,
hydraulic fluid is bypassed to return and system
pressure will be below the operating pressures required
to drive the hydraulic starter on the gas turbine engine.
d. Depress switch No. 30 on the data selector 1A2 (7,
SOLENOID switchlight (30, figure 1-24). Verify an
indication of fuel pressure on the FUEL FLOW monitor
unit (16, figure 1-23).
If the temperature Indicated on the
EXHAUST GAS TEMP meter (38,
figure 1-24) exceeds the specified
START switch (31), and IGNITION
switch (32) on operator's panel 3A3 a
second time. This action will cut off
fuel and ignition and will allow the
EGT to drop. Failure to observe this
warning will result In damage to the
equipment and may cause Injury to
e. Simultaneously depress the START switch (31),
IGNITION switch (32) and TIMER START switchlight
unit (35). Hold all switches except timer in energized
position until lightoff. If lightoff occurs within the
maximum specified starting time, release the starting
and timing switches and observe rising EGT on the
EXHAUST GAS TEMP meter (38). If the HYD TEMP
HIGH indicator (2, figure 1-26) comes on, deenergize
the starting and timing switches and allow the hydraulic
fluid to cool before a restart. One restart may be
attempted. If lightoff does not occur at restart,
deenergize all systems and troubleshoot the unit as
specified in chapter 5 of this technical manual.
f. For T73 engine test only, advance the NI throttle to
the idle speed factor recorded in Section VIII,
Installation of T73 Engine for Testing, paragraph 2-
g. At lightoff, monitor the EXHAUST GAS TEMP
temperature observed does not exceed specified
h. Monitor the instrumentation and note that engine
test parameters agree with the applicable engine test
procedures, then accomplish the procedures outlined in
i. Deenergize hydraulic start system (4, figure 1-26).