2.
Engine Performance Deterioration Test
A. Check fuel quantities are as follows:
Tanks No. 1 and 2: 1600 +100 lbs (725 +45 kgs)
Center tank: No restriction
B. If center tank contains fuel, manually close center tank boost pump removal valves. Refer to AMM 28-22-41/401 for valve handle access.
C. Make sure the fuel crossfeed valve is closed.
D. Start both engines (AMM 71-09-100/201).
E. Operate the engines, with the boost pumps on, at IDLE for a minimum of 2 minutes.
NOTE: Extend the engine warm up time under very cold ambient conditions.
(1) To operate any of the fuel boost pumps, you must be in the flight compartment to continuously monitor the fuel quantity and the low pressure indication in the fuel tank.
WARNING: DO NOT OPERATE ANY FUEL BOOST PUMP IF THE LOW PRESSURE LIGHT COMES ON AND STAYS ON. FUEL VAPORS IN THE TANK MAY IGNITE AND CAUSE A FIRE OR EXPLOSION.
(a) Immediately put the applicable fuel boost pump switch(es) to OFF if the LOW PRESSURE light comes on and stays on.
NOTE: When defueling or transferring fuel with minimum backpressure to the pumps, it is possible for the low pressure light(s) to be on. In this case, monitor the tank quantity and put the pump switch(es) to OFF if the tank quantity is not changing.
F. After 2 minutes, make a record of N1, N2, and fuel flow for each engine.
G. One engine at a time, turn off the applicable boost pumps.
H. Operate the engines at IDLE for a minimum of 5 minutes.
I. Observe N1, N2, and fuel flow for deterioration or fluctuation. If deterioration or fluctuation is noted, perform vacuum test per par. 3.
J. Shut down engines.
K Open center tank boost pump removal valves (if closed).
NOTE: Ensure that removal valve is open before installing boost pump access panel.
3. Engine Fuel Feed Lines/Fitting Vacuum Test
A. Equipment and Materials
(1)
Vacuum Pump
(2)
Vacuum Gage, 0-30 In Hg, accurate to + 1 inch
(3)
Catch Tank -5 gallon -capable of withstanding one atmosphere of vacuum.
(4)
Lock assembly, ME 65-16713
(5)
Adapter, MS24398-16-6
(6)
Plug, MS21913-16
(7)
Shutoff valve
(8)
Tee, 3/8 inch
(9)
Hose, 3/8 inch
505
May 01/03 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 28-22-0 Page 201
B. Prepare for Test
(1)
Defuel airplane (AMM 28-23-0/201).
(2)
Manually close all boost pump removal valves. Refer to AMM 28-22-41/401 for valve handle access.
(3)
On airplanes with boost pump bypass valves with valve lock actuating arm, manually close valves by removing access plugs and inserting lock assembly.
(4)
On ALL EXCEPT airplanes with boost pump bypass valves with valve lock actuating arm:
(a)
Purge fuel tanks (AMM 28-10-0/201)
(b)
Get access to boost pump bypass valves through access panel No. 1 and appropriate rib access openings.
(c)
Remove bypass valves per AMM 28-22-61/401 and install caps on bypass valve inlet fuel lines.
(5)
Ensure that refueling valves and defueling valve are closed.
(6)
Ensure that engine fuel shutoff valves and crossfeed valve are open.
(7)
Drain engine fuel feed lines into 5-gallon container by opening fuel filter drain port. Close drain port and lockwire (AMM 71-00/401).
(8)
Disconnect each engine fuel feed hose at its lower end.
C. Perform vacuum test
(1)
Connect vacuum test equipment (Fig. 201) to one of the disconnected engine fuel feed hoses.
(2)
Install plug in other disconnected engine fuel feed hose.
(3)
With shutoff valve (Fig. 201) open, start vacuum pump. Apply 17-18 inches mercury. If unable to obtain 17-18 In-Hg., proceed to step (5).
(4)
Close shutoff valve (Fig. 202) and shut off vacuum pump. Monitor vacuum gage for 5 minutes.
(a)
If vacuum change is less than 1 IN-HG in five minutes, proceed to par. D.
(b)
If vacuum change is greater than 1 IN-HG in five minutes, proceed to (5).
(5)
If not previously done, purge and get access to all fuel tanks (AMM 28-10-0/201).
(6)
With vacuum pump operating and shutoff valve fully open, check fuel feed lines and couplings for audible air leaks (Fig. 202).
(a)
If coupling is leaking, disassemble coupling, replace O-rings, and reassemble coupling (AMM 28-22-141/401).
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