(4)
Retard thrust lever to idle position. Calculate 95% of takeoff N2.
(5)
After approximately 70 seconds at idle, advance thrust lever in 1 second or less from idle to takeoff mark on control stand determined in step (3) above.
NOTE: If engine has been operated at takeoff power for longer than 3 minutes, operate engine at idle for 3 to 5 minutes prior to performing engine acceleration time check.
(6)
Record engine acceleration time; time elapsed from initial advancement of thrust lever until engine has reached 95% of takeoff N2 rpm determined in step (4). Approximate acceleration time at sea level is between 5 and 6 seconds with engine bleed air off.
NOTE: Maximum acceleration time is subject to pressure altitude. Acceleration time stated above may be increased by 0.30 seconds for each 1000 feet increase in pressure altitude above sea level.
(7)
Stabilize at takeoff setting for 2 to 3 seconds, and decelerate engine to idle by retarding the thrust lever to idle in 1 second or less. Ensure that engine decelerates smoothly and stabilizes at idle rpm. Any flameout is cause of rejection of the fuel control.
NOTE: If fuel control is replaced, refer to 71-00, Power Plant - A/T for testing to be accomplished prior to continuing operational procedures.
(8)
If acceleration time exceeds 6.0 seconds at sea level, repeat above steps (5) thru (8) until three satisfactory accelerations and decelerations have been completed.
(9)
Normal acceleration time is 5 to 6 seconds at sea level. If average time for engines receiving three acceleration checks exceeds 6.0 seconds, it should be reported as an engine discrepancy and corrected before next takeoff.
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71-00 Page 508 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. May 01/99
NOTE: Maximum acceleration time is subject to pressure altitude. Acceleration time stated above may be increased by 0.30 seconds for each 1000 feet increase in pressure altitude above sea level.
L. Test H - Vibration Check (Fig. 502)
(1)
Install one vibration sensor on the inlet and one on the rear case of the engine.
(2)
Connect the sensors to the vibration recording system which includes a 40-Hz filter.
(3)
Determine takeoff EPR (Ref 71-00-30, Trim Procedure).
(4)
Start the engine (Ref 71-00 MP).
(5)
Operate the engine at idle until the oil temperature is a minimum of 100°F (38°C).
(6)
Slowly increase the speed in 2-3 minutes from idle to takeoff EPR.
(7)
Monitor the vibration sensors during the speed increase.
(8)
Record the maximum inlet and rear case sensor amplitudes and the N1 and N2 values for these amplitudes during the speed increase.
(9)
Operate the engine for 30 seconds at takeoff EPR.
(10)
Slowly decrease the speed in 2-3 minutes from takeoff to idle.
(11)
Monitor the vibration sensors during the speed decrease.
(12)
Record the maximum inlet and rear case sensor amplitudes and the N1 and N2 values for these amplitudes during the speed decrease.
(13)
Operate the engine at idle for 5 minutes.
(14)
Stop the engine.
(15)
The maximum vibration values recorded must not be more than the limits that follow:
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May 01/00 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 71-00 Page 509
Sensor Location Single Amplitude Double Amplitude
Inlet Section
Both No. 1 and 0.0025 inch 0.005 inch
No. 6 - Non-oil (2.5 mils) (5.0 mils)
Damped
Both No. 1 and 0.002 inch 0.004 inch
No. 6 - Oil (2.0 mils) (4.0 mils)
Damped
Rear Section
0.0015 inch 0.003 inch
(1.5 mils) (3.0 mils)
Repaired Acceptance Limits Reference Vibration Levels
NOTE: These limits are correct only when the vibration sensors are attached at the locations shown in Fig. 502 and only when the low frequency filter (40 Hz) is in the vibration monitor circuit.
Sensor Location Single Amplitude Double Amplitude
Inlet Section
Both No. 1 and 0.0035 inch 0.007 inch
No. 6 - Non-oil (3.5 mils) (7.0 mils)
Damped
Both No. 1 and 0.0025 inch 0.005 inch
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