(b)  
After 30 seconds, make a record of the average N1 VIB, the
 average N2 VIB, %N1, and %N2.

 NOTE: The average vibration is used because the vibration
____ indications can have small changes when the engine is stable. The average vibration is the middle value between the minimum and the maximum vibration indications with the engine stable.
 S 815-242-N00
 CAUTION: USE THIS VIBRATION GUIDELINE ONLY FOR THE GROUND TEST OF THE
_______ ENGINES DURING MAINTENANCE. THE VIBRATION GUIDELINE IS NOT FOR FLIGHT OPERATIONS.
 (13) The engine must not have an average vibration indication more than the vibration guidelines shown below, after 30 seconds of stable engine operation.
 NOTE: If you do the trim balance procedure (AMM 72-31-00/501), use
____
 the limits given for that procedure.

 (a)  
N1 - 4.0 units (4.0 mils single amplitude)

 (b)  
N2 - 2.5 units (1.25 inches/second)

 (c)  
BB - 3.0 units (1.8 inches/second)

 (d)  
If the average vibration indication is more than the vibration guideline, do the necessary corrections (FIM 71-FAULT CODE DIAGRAM, Vibration - Fault Codes).

 S 865-221-N00
 (14)
 Operate the engine at idle for 5 minutes to let the engine become cool.

 S 865-089-N00

 (15)
 Use the Power Plant Operation (Normal) procedure to do the engine shutdown (AMM 71-00-00/201).

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TEST NO. 9 - PERFORMANCE TEST
_____________________________
 TASK 71-00-00-705-032-N00
 11. Test No. 9 - Performance Test
_____________________________
 A. General
 (1)  
This test gives the instructions for an on-the-wing test of the engine in replacement of a test cell operation after a module replacement.

 (2)  
A replacement of a module can cause a change in the items that follow: engine performance, engine EGT margin, compressor surge margin, rotor speeds, turbine cooling and bearing thrust loading. This test is necessary as shown in the Power Plant Test Reference Table to keep the engine performance and safety.

 (3)  
You can use these airplane displays for the performance test if all systems operate correctly: EPR, %N1, %N2, and EGT.

 (4)  
This test is done at approximately 1.25 EPR to keep the power level and the time at high power to a minimum. This is the only necessary engine test that examines the engine component failures. Accurate instruments are necessary to measure the engine pressures.

 (5)  
A vibration check can be necessary during this test. Refer to the Power Plant Test Reference Table for the necessary test.

 (6)  
A power acceleration/deceleration time check is necessary during this test.

 (7)  
Refer to AMM 71-00-00/201 for the engine operation limits, procedures, safety precautions, and other related data.

 (8)  
Do not do this test when it is necessary to use the nacelle anti-icing system because of the weather conditions. The test tables are made for a no-airbleed condition.

 (a)  If you must do the test with the anti-ice on, you must keep the anti-ice system on during the full operation. For the last 30 seconds at each power level, turn the anti-ice off and get the necessary engine data.

 (9)  
Ice on the engine can occur when there is visible moisture and the outside air temperature (OAT) is less than 46°F(8°C).

 NOTE: The visible moisture is rain, snow or fog (when you can see
____ a distance of 1 mile (1.6 kilometer) or less).
 (10) Instrument Limits
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////////////////////////A / PW4000 SERIES /747-400 / ENGINES/MAINTENANCE MANUAL ////////////////////////
TEST NO. 9 - PERFORMANCE TEST
_____________________________
 ~.................................................................... | Parameter | Range | Accuracy | ...................................................................... | Ambient Temperature | -40°F(-40°C) to | | 0.5°F | | | +120°F(+49°C) | (| 0.25°C) | ...................................................................... | Ambient Pressure | 0-20 psia | | 0.01 psi | ...................................................................... | PT2.5 (if available) | 0-50 psig | | 0.06 psi | ...................................................................... | PS3 | 0-400 psig | | 0.5 psi | ...................................................................... | PS4I | 0-400 psig | | 0.5 psi | 2........................…......................…....................1
　
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