(a) Find out if the weight location is centered on one screw hole
or is between two screw holes.
(b) Get the new balance screws (Figs. 508 and 509).
(c) Make a record of the new balancing screws and their locations
on a balancing screw location chart (Fig. 502).
(d) Remove the weights that were installed for the vectorial
analysis engine run.
(e) Install the new screws which are written on Fig. 502.
NOTE:____ The torque value for the balancing screws is
70-75 pound-inches (8.0-8.5 Newton meters).
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú
72-31-00
ALL ú ú C08 Page 564 ú Mar 12/00
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
////////////////////////A / /
CFM56 ENGINES
737-300/400/500/ /MAINTENANCE MANUAL ////////////////////////
(f)
Do a last engine run to do a check for the remaining imbalance with the one-shot plot procedure. 1) Make a record of the U4 values and A4 values.
(g)
If the vibration amplitudes are not more than the limits, the trim balance procedure is completed. 1) Do this subsequent task: Put the Airplane Back to Its
Usual Condition.
(h)
If the imbalance continues to be more than the limits, do troubleshooting, as follows, of the vibration indicating system to make sure the indications are correct: 1) Examine all of the data from engine runs to make sure you
_____________ calculated the results correctly.
________________________________
2) Make sure the instruments were set and calibrated with the correct values.
3) Examine the condition of all connectors.
NOTE: Dirty or wet connectors can cause incorrect
____
vibration indications.
4) Do a check for accelerometer mounting brackets that are
loose.
5) Make sure all of the leads are satisfactorily attached (with clamps, tape, or other fasters) at locations that are not less than 6 inches (15 cm) apart.
NOTE: Leads that are free to move or shake can cause
____
incorrect vibration signals.
6) Install the initial balance screws again from Fig. 502.
NOTE: The torque value for the balancing screws is
____ 70-75 pound-inches (8.0-8.5 Newton meters).
7) Do a second initial engine run.
______
8) Compare the amplitude and phase angle indications of the
second initial engine run with the results of the first
______ _____ initial engine run.
9) Do the one-shot procedure with the data from the second
______ inital engine run. 10) Compare the calculated balance weight and angle with balance weight and angle that you calculated from the first
_____ initial engine run (W1 at A1).
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú
72-31-00
ALL ú ú C08 Page 565 ú Mar 12/00
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
////////////////////////A / /
CFM56 ENGINES
737-300/400/500/ /MAINTENANCE MANUAL ////////////////////////
11) If the W1 and A1 values of the two engine runs are almost the same, the equipment was installed correctly during the first engine run. a) Do this subsequent task: Put the Airplane Back to Its
Usual Condition.
NOTE: The last weight configuration that was
____ calculated (WO4 at AO4, which is more than the limits) is correct. Thus, it is not possible to correct the vibration problem sufficiently without the removal of the engine.
12) If the W1 and A1 values of the two engine runs are too different, it is possible that the equipment was incorrectly installed for the first engine run. a) If the imbalances from the second initial engine run
______ are lower than those from the first initial engine run,
_____ do as follows.
1. Use the values from the second initial engine run
_ to do the procedure again.
(i) If the analyzer procedure decreased the Fan vibration levels as follows, do the Two-Plane Trim Balance Procedure. 1) The vibration levels of the No. 1 bearing (or FFCCV) were
decreased to not more than 3.5 mils DA. 2) The vibration levels of the TRF were not decreased to less
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：737-300 400 500 AMM 飞机维护手册 ENGINE 发动机 1(99)
