(2)
Remove the test thermocouple from the APU.
(3)
Install the EGT thermocouple probe (AMM 49-71-21/401).
B. Operate the APU (AMM 49-11-0/201):
(1)
Let the APU become stable for 1 to 2 minutes with no load applied.
(2)
Record the EGT indication from the EGT indicator in the cockpit.
(3)
Compare the EGT indication from step 4.C.(3)b) and step 7.B.(2).
(4)
If the difference of the two EGT indications is more than 5°C (41°F), do the adjustment/test of the EGT indicating system (AMM 49-71-0/501).
8. Restore Airplane to Normal Configuration
A. Position lower shroud against upper shroud and close shroud latches.
CAUTION: MAINTAIN A MINIMUM CLEARANCE OF 0.18 INCH BETWEEN ENGINE PLUMBING, FIRE DETECTOR, CLAMPS AND INSIDE SURFACE OF LOWER SHROUD.
CAUTION: EXERCISE EXTREME CARE NOT TO DAMAGE SHROUD DRAIN LINES WHEN HANDLING SHROUD.
B. Disengage APU compartment access door support rods and stow rods. Close and latch access door.
C. Remove placards and position BATTERY SWITCH to OFF if electrical power is no longer required on airplane.
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49-52-32 Page 504 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. Aug 01/94
SURGE BLEED VALVE - REMOVAL/INSTALLATION
1. Prepare for Surge Bleed Valve Removal
A. Position BATTERY SWITCH and APU START SWITCH to OFF and placard "APU in-work."
B. Open the circuit breaker on M280 module-APU accessory unit on E3-3 electronic shelf.
C. Open APU compartment access door latches and open access door. Install door support rods.
D. Support lower shroud, open shroud latches and remove shroud.
CAUTION: EXERCISE EXTREME CARE NOT TO DAMAGE SHROUD DRAIN LINES WHEN HANDLING SHROUD.
2. Remove Surge Bleed Valve
A. Disconnect electrical connector (Fig. 401).
B. Remove lockwire and remove attaching screws.
C. Remove surge bleed valve and discard O-ring.
3. Install Surge Bleed Valve
A. Position new O-ring in groove on flange of new or serviceable valve.
B. Position valve on turbine plenum and install washers and screws (Fig. 401).
C. Tighten screws to torque of 20 to 25 pound-inches and lockwire.
D. Connect electrical connector to valve.
504
Nov 15/70 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 49-52-41 Page 401
4. Restore Airplane to Normal Configuration
A. Position lower shroud against upper shroud and close shroud latches.
CAUTION: MAINTAIN A MINIMUM CLEARANCE OF 0.18 INCH BETWEEN ENGINE PLUMBING, FIRE DETECTOR, CLAMPS AND INSIDE SURFACE OF LOWER SHROUD.
EXERCISE EXTREME CARE NOT TO DAMAGE SHROUD DRAIN LINES WHEN HANDLING SHROUD.
B. Disengage APU compartment access door support rods and stow rods. Close and latch access doors.
C. Close the circuit breaker on M280 module-APU accessory unit on E3-3 electronic shelf.
D. Remove placards and position BATTERY SWITCH to ON.
E. Perform operational test of surge bleed valve (Ref Adjustment/Test).
504
49-52-41 Page 402 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. Sep 20/82
565 Surge Bleed Valve Installation
Jun 20/86 Figure 401 49-52-41
Page 403
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
SURGE BLEED VALVE-ADJUSTMENT/TEST
1. General
A. Performing the surge bleed valve test requires that ground personnel be stationed near the APU (APU access doors closed) while it is operating at rated rpm. Because the surge bleed valve operates only when the APU rpm is above 95% and the airplane is airborne, testing on the ground necessitates tricking the surge bleed valve circuitry into believing the airplane is in flight. This is accomplished by opening circuit breaker C404, LANDING GEAR LIGHTS, on panel P6-2.
CAUTION: EAR PROTECTION MUST BE WORN BY PERSONNEL WORKING IN AREA OF APU BEING TESTED.
2. Test Surge Bleed Valve
A. Operate APU - Engine Start Procedure (Ref 49-11-0, Maintenance Practices).
B. Ensure all of following valves are closed:
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