DOC AIRBUS | AMM A320FVisual Examination of the Fan Blade Galvanic Isolation [PW11]
TASK 72-11-03-210-803-A
Visual Examination of the Fan Blade Galvanic Isolation
Use this procedure to do an electrical resistance inspection of the fan blade to extend the continue-in-service limit when there is missing coat in 2.0 inches (50.8 mm) from the leading edge sheath or ground tab.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Consumable Materials
C. Work Zones and Access Panels
D. Referenced Information
3. Job Set-up
Subtask 72-11-03-941-058-A ** ON A/C NOT FOR ALL
Subtask 72-11-03-860-054-A ** ON A/C NOT FOR ALL
[Rev.10 from 2021]
2026.04.01 13:02:17 UTC
Visual Examination of the Fan Blade Galvanic Isolation
WARNING:
BE CAREFUL WHEN YOU DO WORK ON THE ENGINE AFTER SHUTDOWN. THE ENGINE CAN STAY HOT FOR A LONG TIME. IF YOU DO NOT OBEY THIS INSTRUCTION, INJURY CAN OCCUR.
WARNING:
BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.
CAUTION:
DO NOT APPLY MORE THAN 250 VOLTS TO THE FAN BLADES. IF YOU DO, DAMAGE TO THE BLADES CAN OCCUR.
ZONE: 400
1. Reason for the JobUse this procedure to do an electrical resistance inspection of the fan blade to extend the continue-in-service limit when there is missing coat in 2.0 inches (50.8 mm) from the leading edge sheath or ground tab.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| No specific | 1 | BRUSH - BRISTLED |
| No specific | 1 | GLOVES - PROTECTIVE |
| No specific | 1 | MAT - PROTECTIVE |
| No specific | 1 | OHMMETER MULTIRANGE |
| REFERENCE | DESIGNATION |
|---|---|
| (Material No.P05-005) | wipe, lint-free |
| (Material No.P11-014) | isopropyl alcohol |
| ZONE/ACCESS | ZONE DESCRIPTION |
|---|---|
| 400 | POWER PLANT, NACELLES AND PYLONS |
| REFERENCE | DESIGNATION |
|---|---|
| TASK 70-27-00-910-804-A | SPOP 208 - Degreasing of Parts by Solvent Wiping |
| TASK 71-00-00-860-833-A | Procedure to Prevent Engine Motoring |
| TASK 72-11-01-000-801-A | Removal of the Inlet Cone |
| TASK 72-11-01-400-801-A | Installation of the Inlet Cone |
| TASK 72-11-03-000-801-A | Removal of the Fan Blades |
| TASK 72-11-03-220-802-A | Visual Inspection of the Fan Blades Surface |
| TASK 72-11-03-400-801-A | Installation of the Fan Blades |
Subtask 72-11-03-941-058-A ** ON A/C NOT FOR ALL
A. Safety Precautions
(1) Do the procedure to prevent engine motoring
(Ref. AMM TASK 71-00-00-860-833).
4. Procedure(1) Do the procedure to prevent engine motoring
(Ref. AMM TASK 71-00-00-860-833).
CAUTION:
WIPE CLEAN ALL PARTS AND TOOLS AS NECESSARY TO REMOVE UNWANTED DEBRIS AND PREVENT DAMAGE TO THE ENGINE.
Subtask 72-11-03-210-053-A ** ON A/C NOT FOR ALL A. Galvanic Isolation Check
(1) Setup:
(a) Find the fan blades at the front of the engine attached to the fan hub. See sheet 1 of the figure:
(b) If the galvanic isolation inspection is done off-wing, remove the applicable fan blades from the engine as follows:
1 Put the MAT - PROTECTIVE in the air intake cowl.
3 Remove the inlet cone (Ref. AMM TASK 72-11-01-000-801).
4 Remove the fan blades as necessary (Ref. AMM TASK 72-11-03-000-801).
(c) Clean each fan blade before you do the galvanic isolation test with the clean and dryP05-005 wipe, lint-free
(d) Wipe the test leads with the clean and dryP05-005 wipe, lint-free
(e) Use the PWA211801 ADAPTER, HOLDER or change the standard clip (Mil-A-A-59466 Type TC). Grind the clip teeth or use a file to make the 0.010 in. (0.254 mm) minimum flat on the top of each tooth. Break the sharp edges to 0.005 in. (0.127 mm) minimum. You can use a smooth clip or a clip with no teeth as an alternative.
Galvanic Isolation Inspection of the Fan Blade (Clip Requirements and Resistance Measurements) ** ON A/C NOT FOR ALL
(2) Isolation measurement:
1 Do not move the leads during the measurement.
(b) Do not touch the blade assembly with your hand or other objects during the measurement.
(c) Make sure that there is the good continuity at the blade tip as follows:
1 Find the test leads and do the steps that follow:
b If the fan blade is removed from the engine for the inspection, touch the both leads to the tip of the fan blade.
2 Turn the OHMMETER MULTIRANGE switch to the "ohm" position in the orange ohm/kilo-ohm area.
3 If the OHMMETER MULTIRANGE reads less than 1 ohm, continue to step 4.A.(2)(d). If the OHMMETER MULTIRANGE reads more than 1 ohm, move the leads to a different location on the tip and do the test again not more than three times.
4 If the OHMMETER MULTIRANGE reads more than 1 ohm after the three tests, locally clean the blade tip by SPOP 208 or with the soft abrasive pad and do the continuity check again (Ref. AMM TASK 70-27-00-910-804).
(d) Measure the sheath to the blade body resistance and the ground tab to the blade body resistance as follows:
1 Turn the OHMMETER MULTIRANGE switch to the "50V" position in the red M-ohm area. If an ohmmeter other than the Megger MIT420/2 is used, select the test voltage between 10 and 50 volts.
2 Connect the two leads as follows:
a If this procedure is done on-wing, keep the black lead between the fan blade and the fan case rub strip area. Remove the red lead clip between the blade tip and the fan case rub strip area. Attach the red lead clip to the titanium Leading Edge (LE) sheath.
Galvanic Isolation Inspection of the Fan Blade - (Leading Edge Sheath to the Body Resistance Check) ** ON A/C NOT FOR ALL
b If the fan blade is removed from the engine for the inspection, keep the black lead in the position at the blade tip. Remove the red lead clip from the blade tip and attach the red clip onto the titanium LE sheath.
3 The red lead is used for the sheath connection and the black lead is used for the blade tip connection. Do not interchange the lead locations.
4 If each lead is in contact with the tip and the LE sheath, push and hold the "test" button on the front of the OHMMETER MULTIRANGE.
5 Record the isolation values as necessary. See Table 7 of the figure:
Galvanic Isolation Inspection of the Fan Blade (Clip Requirements and Resistance Measurements) ** ON A/C NOT FOR ALL
6 Remove the red lead clip from the titanium LE sheath and connect it to the titanium ground tab near the base of the LE sheath.
Galvanic Isolation Inspection of the Fan Blade - (Ground Tab to the Body Resistance Check) ** ON A/C NOT FOR ALL
7 If the inlet cone is attached, hold the lead clip in the position during the measurement when the inspection is done on-wing.
8 If each lead is in contact with the ground tab and tip, push and hold the "test" button on the front of the OHMMETER MULTIRANGE.
9 Record the isolation values and send the results to P&W for the analysis. See Table 7 of the figure:
Galvanic Isolation Inspection of the Fan Blade (Clip Requirements and Resistance Measurements) ** ON A/C NOT FOR ALL
10 If applicable, do the isolation measurement step 4.A.(2)(c)1_ thru step 4.A.(2)(d)9_.
(3) Permitted limits:
(a) The isolation values of 1 M-ohm or more are permitted.
(b) For a blade which the isolation value is less than 1 M-ohm, do the steps that follow:
1 Clean the interfaces of the blades with the isopropyl alcohol (Material No.P11-014) by SPOP 208 (Ref. AMM TASK 70-27-00-910-804). See sheet 3 of the figure:
2 Use the BRUSH - BRISTLED and clean the fan blade tip from the LE to 0.5 in. (12.70 mm) aft of the LE sheath trailing edges.
5 Do the isolation measurement step 4.A.(2)(c)1_ thru step 4.A.(2)(d)9_ again.
6 If, during the second set of the isolation measurement tests, the isolation values for the blades are not less than 1 M-ohm, the blades are satisfactory.
7 If, in the second set of the isolation measurement tests, the isolation values for a blade are less than 1 M-ohm, set the OHMMETER MULTIRANGE to 100 volts and do step 4.A.(2)(c)1_ thru step 4.A.(2)(d)9_ again.
8 If the isolation values are not in the limits, set the OHMMETER MULTIRANGE to 250 volts and do step 4.A.(2)(c)1_ thru step 4.A.(2)(c)9_.
9 If the isolation values are not in the limits, contact P&W.
(4) If necessary, install the fan blades (Ref. AMM TASK 72-11-03-400-801).
(5) If necessary, install the inlet cone (Ref. AMM TASK 72-11-01-400-801).
5. Close-up(1) Setup:
(a) Find the fan blades at the front of the engine attached to the fan hub. See sheet 1 of the figure:
(b) If the galvanic isolation inspection is done off-wing, remove the applicable fan blades from the engine as follows:
1 Put the MAT - PROTECTIVE in the air intake cowl.
WARNING:
USE PROTECTIVE GLOVES TO PREVENT POSSIBLE INJURY TO THE HANDS WHEN YOU TOUCH OR HOLD THE FAN BLADES. THE BLADE EDGES ARE SHARP AND CAN CUT THE HANDS.
2 Wear the GLOVES - PROTECTIVE when you touch the blades. 3 Remove the inlet cone (Ref. AMM TASK 72-11-01-000-801).
4 Remove the fan blades as necessary (Ref. AMM TASK 72-11-03-000-801).
(c) Clean each fan blade before you do the galvanic isolation test with the clean and dry
(d) Wipe the test leads with the clean and dry
(e) Use the PWA211801 ADAPTER, HOLDER or change the standard clip (Mil-A-A-59466 Type TC). Grind the clip teeth or use a file to make the 0.010 in. (0.254 mm) minimum flat on the top of each tooth. Break the sharp edges to 0.005 in. (0.127 mm) minimum. You can use a smooth clip or a clip with no teeth as an alternative.
Galvanic Isolation Inspection of the Fan Blade (Clip Requirements and Resistance Measurements) ** ON A/C NOT FOR ALL NOTE: The table shows only the general design qualities as a reference and is not shown to limit the specified manufacturing procedures.
NOTE: The clip teeth must be free to engage after the adjustment.
(f) Attach the red and black leads to the OHMMETER MULTIRANGE. (2) Isolation measurement:
NOTE: Two people are recommended for this inspection.
(a) The measurements will take approximately five seconds.1 Do not move the leads during the measurement.
(b) Do not touch the blade assembly with your hand or other objects during the measurement.
(c) Make sure that there is the good continuity at the blade tip as follows:
1 Find the test leads and do the steps that follow:
WARNING:
DO THIS PROCEDURE CAREFULLY. IF YOU DO NOT OBEY ALL THE INSTRUCTIONS IN THIS PROCEDURE, THE THRUST REVERSER HALF CAN CLOSE QUICKLY. IF PERSONS ARE BETWEEN THE THRUST REVERSER HALF AND THE ENGINE, THEY CAN GET INJURED.
a If the galvanic inspection is done on-wing, put each lead between the blade tip and the fan case rub strip area.b If the fan blade is removed from the engine for the inspection, touch the both leads to the tip of the fan blade.
2 Turn the OHMMETER MULTIRANGE switch to the "ohm" position in the orange ohm/kilo-ohm area.
3 If the OHMMETER MULTIRANGE reads less than 1 ohm, continue to step 4.A.(2)(d). If the OHMMETER MULTIRANGE reads more than 1 ohm, move the leads to a different location on the tip and do the test again not more than three times.
4 If the OHMMETER MULTIRANGE reads more than 1 ohm after the three tests, locally clean the blade tip by SPOP 208 or with the soft abrasive pad and do the continuity check again (Ref. AMM TASK 70-27-00-910-804).
(d) Measure the sheath to the blade body resistance and the ground tab to the blade body resistance as follows:
1 Turn the OHMMETER MULTIRANGE switch to the "50V" position in the red M-ohm area. If an ohmmeter other than the Megger MIT420/2 is used, select the test voltage between 10 and 50 volts.
2 Connect the two leads as follows:
a If this procedure is done on-wing, keep the black lead between the fan blade and the fan case rub strip area. Remove the red lead clip between the blade tip and the fan case rub strip area. Attach the red lead clip to the titanium Leading Edge (LE) sheath.
Galvanic Isolation Inspection of the Fan Blade - (Leading Edge Sheath to the Body Resistance Check) ** ON A/C NOT FOR ALL 3 The red lead is used for the sheath connection and the black lead is used for the blade tip connection. Do not interchange the lead locations.
4 If each lead is in contact with the tip and the LE sheath, push and hold the "test" button on the front of the OHMMETER MULTIRANGE.
5 Record the isolation values as necessary. See Table 7 of the figure:
Galvanic Isolation Inspection of the Fan Blade (Clip Requirements and Resistance Measurements) ** ON A/C NOT FOR ALL Galvanic Isolation Inspection of the Fan Blade - (Ground Tab to the Body Resistance Check) ** ON A/C NOT FOR ALL 8 If each lead is in contact with the ground tab and tip, push and hold the "test" button on the front of the OHMMETER MULTIRANGE.
9 Record the isolation values and send the results to P&W for the analysis. See Table 7 of the figure:
Galvanic Isolation Inspection of the Fan Blade (Clip Requirements and Resistance Measurements) ** ON A/C NOT FOR ALL (3) Permitted limits:
(a) The isolation values of 1 M-ohm or more are permitted.
(b) For a blade which the isolation value is less than 1 M-ohm, do the steps that follow:
1 Clean the interfaces of the blades with the isopropyl alcohol (Material No.P11-014) by SPOP 208 (Ref. AMM TASK 70-27-00-910-804). See sheet 3 of the figure:
2 Use the BRUSH - BRISTLED and clean the fan blade tip from the LE to 0.5 in. (12.70 mm) aft of the LE sheath trailing edges.
NOTE: It is not necessary to clean the fan blade tip if the fan blade is installed on the engine. If the isolation value is less than 1 M-ohm, it is recommended to remove the fan blade from the engine to make the fan blade easier to clean.
3 Clean the ground tab. NOTE: If the fan blade is installed on the engine, only clean the surfaces that you can see.
4 Inspect the blade for damage (Ref. AMM TASK 72-11-03-220-802). 5 Do the isolation measurement step 4.A.(2)(c)1_ thru step 4.A.(2)(d)9_ again.
6 If, during the second set of the isolation measurement tests, the isolation values for the blades are not less than 1 M-ohm, the blades are satisfactory.
7 If, in the second set of the isolation measurement tests, the isolation values for a blade are less than 1 M-ohm, set the OHMMETER MULTIRANGE to 100 volts and do step 4.A.(2)(c)1_ thru step 4.A.(2)(d)9_ again.
8 If the isolation values are not in the limits, set the OHMMETER MULTIRANGE to 250 volts and do step 4.A.(2)(c)1_ thru step 4.A.(2)(c)9_.
9 If the isolation values are not in the limits, contact P&W.
(4) If necessary, install the fan blades (Ref. AMM TASK 72-11-03-400-801).
(5) If necessary, install the inlet cone (Ref. AMM TASK 72-11-01-400-801).
Subtask 72-11-03-860-054-A ** ON A/C NOT FOR ALL
A. Put the aircraft back to its initial configuration.
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Remove the WARNING NOTICE(S).
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Remove the WARNING NOTICE(S).