begins.
3) Engine should start and accelerate smoothly as indicated by the following instruments: a) Oil pressure at gage (8) b) Engine speed at indicator (15) c) Control air pressure at gage (12) d) Fuel pressure at gage (2) e) Ignition light (26) will illuminate f) Exhaust gas temperature at indicator (7) (actuate EGT transfer switch (27)
4) When oil pressure reaches 3.5 to 4.5 psi as indicated on gage (8), ignition circuit will be energized as indicated by ignition light (26) illuminating and fuel solenoid valve should open, allowing fuel flow as indicated on gage (2). This also indicates satisfactory operation of engine sequencing oil pressure switch.
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5) When engine speed reaches approximately 50% as indicated on indicator (15), electronic speed switch should actuate to break starter motor circuit as indicated by light (19) going off.
6) When engine oil pressure reaches 45 to 55 psi as indicated on gage (8), oil pressure light (17) should go off, indicating satisfactory operation of engine low oil pressure switch.
7) When engine speed reaches approximately 75% as indicated on indicator (15), engine oil pressure would be 90 to 100 psi as indicated on gage (8), and should remain at this pressure for engine operation above 75% speed. Oil pressure should not fluctuate more than 3 psi during steady state operation.
8) When engine speed reaches 95% as indicated on indicator (15), electronic speed switch will terminate ignition (light (26) will extinguish) and energize elapsed time indicator as indicated by light (28) illuminating and engine elapsed time indicator starting to record time.
9) With no load applied, engine speed should stabilize at 102% rpm (max) as indicated on indicator (15).
(e)
On forward overhead panel, position APU BLEED valve switch to ON.
(f)
With cabin temperature controls set at 80°F and AUTO, position air conditioning R PACK and L PACK valve switches to ON.
(g) Position tester load switch (29) to ON. Load light (30) will illuminate. 1) Measure time from actuation of tester load switch until fuel pressure gage (2) shows first peak reading. This should occur within 12 to 14 seconds, indicating that valve has reached full open position. 2) Observe engine speed on indicator (15) at load application. Speed drop should not exceed 2% engine rpm and speed should stabilize at 98% (min) engine rpm. 3) Observe engine exhaust gas temperature on indicator (7) at full bleed air load operation. This temperature is load control thermostat controlling temperature and should not exceed 650°C. Actuate EGT transfer switch (27) to observe EGT on tester.
4) Check that EGT on the tester gage agrees with cockpit gage.
(h)
Open control bleed (14) and observe that fuel pressure (2) and EGT (7) will decay and RPM (15) will increase indicating bleed air valve closing.
(i)
Close control bleed (14) and note that fuel pressure, EGT and RPM will return to original readings indicating bleed air valve has reopened.
(j)
Position tester load switch (29) to OFF. Load light (30) will extinguish.
(k)
Position air conditioning R PACK and L PACK valve switches to OFF.
(l)
Position APU BLEED valve switch to OFF.
(m)
Allow engine to operate at no load-governed speed for 1 minute (minimum).
(n)
Position power switch (16) to ON and momentarily actuate overspeed switch (31). APU will shut down and overspeed light (33) will illuminate.
(o)
Position APU master switch to OFF.
(p)
Position BATTERY switch to OFF and placard.
(q)
Gain access to M280 APU control module and press overspeed reset switch.
(r)
Position No. 1 forward boost pump switch to OFF.
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(6)
Disconnect Gas Turbine Engine Tester from Engine
(a)
Check that BATTERY SWITCH is OFF and placarded.
(b)
Remove oil pressure hose assembly (38) from tester coupling (9) and from oil pressure connection port (39) on oil pressure switch manifold.
(c)
Install cap on oil pressure connection port (39) and on oil pressure switch manifold test port.
(d)
Remove control air hose assembly (40) from tester coupling (11) and from control air pressure port (41) on thermostat plumbing.
(e)
Install cap on control air pressure port (41) and on tester control air pressure coupling (11).
(f)
Remove fuel pressure hose assembly (42) from tester coupling (3) and from fuel pressure port (43) on fuel control unit.
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