Eddy-Current Inspection of the Fan Blade Leading Edge [CFMI]

TASK 70-52-00-250-001-A
Eddy-Current Inspection of the Fan Blade Leading Edge

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
856A2682G01	1	EDDY CURRENT INSTRUMENT

B. Referenced Information

REFERENCE	DESIGNATION
Indications (Typical) on the Screen
Positioning of the Probes

3. Job Set-up
Subtask 70-52-00-869-052-A ** ON A/C NOT FOR ALL

A. Eddy-Current Inspection of the Fan Blade Leading Edge
(1) This procedure describes the general equipment, techniques and procedures required to conduct high frequency MHz manual Eddy-current inspection of the fan blade leading edge.
(2) The following requirements shall be met by inspection personnel:
(a) Personnel performing this inspection must be certified to one of the following: NAS 410 / EN4179 level 2 minimum or any equivalent standard as recognized by the Airworthiness Authority of the personnel.
(b) Personnel performing this inspection should receive practical training in the use of this procedure and must demonstrate proficiency in the calibration and evaluation routines before accept/reject authority is delegated.
(c) Training per this procedure does not imply personnel certification per NAS 410 / EN4179 level 2 minimum or any equivalent standard as recognized by the Airworthiness Authority of the personnel.
(3) The following documents shall form a part of this procedure to the extent specified herein. Unless a specific issue is specified, the latest revision shall apply.
(a) Appropriate equipment instruction manuals.
(b) NAS 410 / EN4179 or any equivalent standard as recognized by the Airworthiness Authority of the personnel.
(c) Appropriate Manual procedure.

Subtask 70-52-00-869-053-A ** ON A/C NOT FOR ALL

B. Equipment
(1) Eddy-Current instruments.
(a) Nortec Model NDT-19, 19e, 19eII, 24 or -3000 Eddyscope.
(b) Rohmann Elostest B1 SDM Eddy current instrument.

NOTE: Any equivalent equipment approved by Snecma/CFM can be used instead of listed above.

(2) Tools and Equipments.
(a) Special Tools.
856A2682G01 EDDY CURRENT INSTRUMENT (856A2682G01)

Tools No.	Description
856A2682G01	Kit containing - a probe 9970 958 389P01, 3MHz, with a spring blade - a probe 9970 958 390P01, 3MHz, with a free head - a calibration bloc 9970 958 391G01 - 2 cables, Teflon tape, red and blue pencils

(b) Standard Tools and Equipment.

NOTE: This tooling will be contained in a CFMI inspection kit. The inspection kit number shall be identified in the applicable manual procedure. A complete inspection kit containing all required tooling can be obtained from CFMI

(3) Consumable Materials.

Code No.	Description
CP1040	Methyl Ethyl Ketone
CP2189	Durite G 422
CP2191	Durite G 421

4. Procedure
Subtask 70-52-00-250-050-A ** ON A/C NOT FOR ALL

A. Eddy-Current Inspection - Procedure
(1) Preparation of the edge.
(a) Clean the edge of the blade with Methyl Ethyl Ketone (Material No. CP1040)
(b) If necessary, lightly remove the small surface defects with a thin abrasive cloth (Material No. CP2189) or (Material No. CP2191).
(2) Calibration.
(a) Initial Calibration

Frequency	3MHz
Rotation	To be adjusted to have a vertical screen indicator
Low pass filter	100Hz
High pass filter	Off
Gain	To be adjusted during calibration procedure (ELOTEST -35dB, NORTEC -50dB)

(b) Calibration procedure with the 9970 958 389P01 or 9970 958 390P01 probe.

CAUTION: MAKE SURE THAT THE PROBE IS IN GOOD CONDITION. LOOK FOR DAMAGED PROBE HEAD OR PROBE WIRE.

1 Install the probe on the Eddy-current instrument.

CAUTION: TAKE CARE TO LET FREE THE MOBILE PART OF THE PROBE.

CAUTION: MAKE SURE THAT THE TEFLON IS CHANGED AT REGULAR TIME.

2 Apply a new small piece of Teflon tape on the coil of each probe.
3 Calibration.

CAUTION: TO PREVENT INCORRECT MEASUREMENTS, DO THE CALIBRATION:

AT THE START AND AT THE END OF THE INSPECTION, EVERY FIFTH BLADE
EACH TIME YOU REPLACE THE COMPONENT
WHEN THE INSTRUMENTATION WAS STOPPED.

a Put the coil away from the notch of the Electro Discharge Machining (EDM) on the non-blended area.
b Set the EDM to zero.

NOTE: The point is in the middle of the screen.

c Examine the surface along the non-blended area with the probe and adjust the gain and rotation to have a peak to peak on full screen with a vertical indication when the coil touches the EDM notch.

Indications (Typical) on the Screen ** ON A/C NOT FOR ALL

d Keep the same parameters and put the coil away from the notch of the EDM.
e Set the EDM to zero on the blended area.
f Examine the bottom of the blended area with the EDM notch.
g If the indication is equal or less than a half of full screen, adjust these following parameters : hand position, movement of examination, gain and rotation to have a full screen indication on the EDM notch of the non-blended area and more than a half full screen in the blended area.

Indications (Typical) on the Screen ** ON A/C NOT FOR ALL

(3) Eddy-current inspection procedure.

CAUTION: YOU MUST PERFORM TWO INSPECTIONS WITH TWO DIFFERENT PROBES BECAUSE OF THE DESIGN OF THE BLADE (SHAPE AND DIFFERENT THICKNESSES) ESPECIALLY IN THE BLENDED AREAS.

(a) Do a first inspection of the leading edge of the blade with the 9970 958 389P01 probe.
1 Put the probe in position with its coil in contact with the pressure face with the same adjustment than for calibration.

Positioning of the Probes ** ON A/C NOT FOR ALL

CAUTION: MAKE SURE THAT THE COIL IS ALWAYS IN CONTACT WITH THE INSPECTED AREA.

2 Move the probe to examine the surface along the leading edge.

NOTE: You can perform this inspection a second time if it is not sufficient.

3 Put the probe in position with its coil in contact with the suction face with the same adjustment than for calibration.

Positioning of the Probes ** ON A/C NOT FOR ALL

CAUTION: MAKE SURE THAT THE COIL IS ALWAYS IN CONTACT WITH THE INSPECTED AREA.

4 Move the probe to examine the surface along the leading edge.

NOTE: You can perform this inspection a second time if it is not sufficient.

NOTE: You can move the probe three times or more across the blade section to make sure that the indication is not a malfunction.

5 Set to zero each time the probe touches a blended area.
(b) Do a second inspection of the leading edge of the blade with the 9970 958 390P01 probe.
1 Put the probe in position with its coil in contact with the pressure face with the same adjustment than for calibration.

Positioning of the Probes ** ON A/C NOT FOR ALL

CAUTION: MAKE SURE THAT THE COIL IS ALWAYS IN CONTACT WITH THE INSPECTED AREA.

2 Move the probe to examine the surface along the leading edge.

NOTE: You can perform this inspection a second time if it is not sufficient.

3 Put the probe in position with its coil in contact with the suction face with the same adjustment than for calibration.

Positioning of the Probes ** ON A/C NOT FOR ALL

CAUTION: MAKE SURE THAT THE COIL IS ALWAYS IN CONTACT WITH THE INSPECTED AREA.

4 Move the probe to examine the surface along the leading edge.

NOTE: You can perform this inspection a second time if it is not sufficient.

NOTE: You can move the probe three times or more across the blade section to make sure that the indication is not a malfunction.

5 Set to zero each time the probe touches a blended area.
(4) Inspection Criteria.
(a) If you measure in a blended or non-blended area an indication equal to or more than 25 percent of full screen, you must do the evaluation of the default.

Indications (Typical) on the Screen ** ON A/C NOT FOR ALL

(b) If you measure in a blended or non-blended area an indication equal to or more than 50 percent of full screen, you must discard the part.

Indications (Typical) on the Screen ** ON A/C NOT FOR ALL

(5) Evaluation of the Default.
(a) Make sure that the calibration procedure was done correctly.
(b) Make sure that two checks were done with the two probes, on suction and pressure faces around the area you examine.
(c) If the indication is equal to or more than 25 percent of full screen, discard the part.

Indications (Typical) on the Screen ** ON A/C NOT FOR ALL

(d) If you have no indication or an indication less than 25 percent of full screen, the part is acceptable.

Indications (Typical) on the Screen ** ON A/C NOT FOR ALL

[Rev.10 from 2021] 2026.04.01 02:18:39 UTC