(c)
Open the core cowl panels (AMM 71-11-06/201).
WARNING: MAKE SURE THAT ENGINE SHUTDOWN OCCURRED NOT LESS THAN 60
_______ MINUTES BEFORE YOU DO THIS PROCEDURE. IF YOU DO NOT WAIT FOR THE ENGINE TO COOL DOWN, INJURY TO PERSONS CAN OCCUR.
(d)
Before you do this test, examine the EPR PT4.95 sensing system for damage with the steps that follow: 1) Make sure that the tube connections are not loose. 2) Make sure that the tubes are not cracked or broken. 3) Make sure that the tubes are not worn through at the clamp
locations. 4) Make sure that the brackets which attach the tubes are not cracked, broken or loose. 5) Make sure that the hoses at the EEC are not damaged.
(e)
Install a clamp from the PWA 102283 kit to each of the EPR probes with the steps that follow: 1) Put the clamp over the front of the probe.
a) Make sure that the ID marking is towards the inner case. b) Make sure that the rubber blockers are over the four pressure sensing ports. 2) Tighten the two knobs equally in small increments until the blockers seal the four sensing ports.
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AS04
EEC
AS24 SEEA
AS13
AS04
AS01 PRE SB PW4ENG 73-106
EPR P4.95 PROBE (2 LOCATIONS)
AS01 AS34
SEE B
AS41 POST SB PW4ENG 73-106
AS27 AS33
AS02
AS03
L-B4724 (0397)
Engine Pressure ratio (EPR) Manifold System Leak Check
Figure 501 (Sheet 1)
G79914
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MAINTENANCE MANUAL
FWD
L-B4857 (0397) PW V
Engine Pressure Ratio (EPR) Manifold System Leak Check Figure 501 (Sheet 2)
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CAUTION:_______DO NOT LET THE AIR PRESSURE GO INTO THE EEC. HIGH PRESSURE AIR CAN CAUSE DAMAGE TO THE EEC.
(f) Do the steps that follow to connect the pressure source: 1) Find the PT4.95 sensing hose (AS13) which is connected to the bottom of the EEC. 2) Hold the EEC adapter with a wrench and disconnect the hose (AS13) from the EEC. 3) Install and tighten the Adapter from the PWA102283 kit to the open end of the hose (AS13). 4) Adjust the regulator on the pressure source to 0 psig (0 kPa).
5) Attach the supply hose from the regulated pressure source to the Adapter on the hose (AS13).
CAUTION: DO NOT LET THE PRESSURE SUPPLY GO TO MORE THAN 10
_______ PSIG (68.9 KPA) WHEN CONNECTED TO THE SENSING SYSTEM. HIGHER PRESSURE CAN CAUSE DAMAGE TO SOME EQUIPMENT, SENSORS OR PROBES.
6) Supply 10 psig (68.9 kPa) to the sensing system.
NOTE: Nitrogen gas is optional to clean dry air for
____
this procedure.
(g)
Do the steps that follow to do the leak test. 1) With 10 psig (68.9 kPa) supplied to the system, close the shutoff valve to isolate the EPR system from the source. 2) Make sure that the pressure in the system does not decrease
more than 0.5 psig (3.4 kPa) in approximately one minute. 3) Use the leak check compound to find a leak in the system.
(h)
If you think you have a leak, do the steps that follow:
CAUTION: BEFORE YOU REPAIR A LEAK, ADJUST THE PRESSURE TO 0
_______ PSIG (0 KPA). IF YOU DO NOT DO THIS, THE PRESSURE CAN INCREASE WHEN YOU REPAIR THE LEAK AND EXCEED THE LIMIT. DAMAGE TO THE SENSOR SYSTEM CAN OCCUR.
1) Adjust the regulator to 0 psig (0 kPa).
2) Repair all the leaks that you find.
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