cfm56 ndt part 7 borescope inspection

CFMI-TP-NT.11 NOVEMBER 30, 1980REVISED MAY 31, 1999

NON-DESTRUCTIVETEST MANUAL

PART 7-BORESCOPE INSPECTION

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PART 7 - BORESCOPE INSPECTION

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CONTENTSPart 7

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TABLE OF CONTENTS

Section Page

72-00-00 Borescope Inspection....................................... 1

R 72-21-00 Borescope Inspection of Low Pressure Compressor............ 1

72-31-00 Borescope Inspection of High Pressure Compressor........... 1

72-42-00 Borescope Inspection of Combustion Section................. l

72-51-00 Borescope Inspection of High Pressure Turbine Nozzle....... l

72-52-00 Borescope Inspection of High Pressure Turbine Blades....... l

72-54-00 Borescope Inspection of Low Pressure Turbine............... 1

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BORESCOPE INSPECTION

1. General.

A. This procedure describes the type of borescope equipment found to beacceptable for inspection of the CFM56 turbofan engine.

B. The borescope is a precision monocular periscope instrument especiallydesigned for the inspection of the inside of turbofan engines throughsmall diameter access holes. The borescope provides a system ofvisually inspecting and taking photographs of selected areas inside theengine. A television camera and viewing screen may be used instead ofvisual examination through the monocular viewer and a television taperecorder may be used in lieu of the photographic method of making arecord. The CFM56 engine has been designed with a substantial number ofaccess holes for viewing critical areas inside the engine.

C. This procedure includes instructions for checking the resolution ofborescopes and fiberscopes.

2. Safety.

The following WARNINGS apply to using borescope equipment.

WARNING: DO NOT EXPOSE YOUR EYES TO THE FULL INTENSITY OF THE XENON ORGAS ARC LIGHT SOURCE.

WARNING: ALL ELECTRICAL EQUIPMENT USED IN INSPECTION SHALL BE PROPERLYGROUNDED.

WARNING: ALL STANDS AND GROUND EQUIPMENT SHALL HAVE SAFETY LOCKS ANDRAILINGS. DO NOT IMPROVISE WITH LADDERS AND BOARDS.

3. Tools, Equipment and Materials.

NOTE: Equivalent substitutes may be used instead of the following items.


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A. Tools and Equipment.

(1) Special Tools.

Tool No. Description

856A1084G02, Cart, Stator ActuatorG03 or G04

856A1142P03 or P04 Motor, Drive-Core EngineRotation (CFM56-2)

856A1310G01 Kit, Borescope Guide - HPTurbine

856A1351P01 Guide Tube, HPT Shroud

856A1320P04, P05, P06 Borescope Set, RigidP07

856A1321P01, P03, P04, P05 Fiberscope Setor P06

856A1324P01 (ALT) Borescope, Videoprobe -Flexible

856A1322P02, P03, P04, Borescope, Light Source SetP07, P08, P09

856A1323G01 Borescope Resolution Monitor

856A1488P01 or P02 Motor Drive - Core EngineRotation (CFM56-5)

856A2002P01, P02, P03 Motor Drive - Core Engineor P04 Rotation (CFM56-3)

856A1815G01, G02 Motor Drive-Core EngineRotation (CFM56-7B)

NOTE: Other borescope systems using either fiber light or distallamps for illumination and a rigid lens optical path may beconsidered acceptable for inspection of the CFM56 turbofanengine if they meet the design specifications of CFMISpecification M50TF3276-S1.

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(2) Standard Tools.

Description Manufacturer

35 mm Camera Local Purchase

Video Monitor Local Purchase

B. Rigid Borescope Set, 856A1320, and Light Source Set, 856A1322. Seefigure 1.

(1) This borescope set consists of the following:

(a) Light source - 110 VAC 60 Hz, 220 VAC 50 Hz, or 110 VAC 400Hz.

(b) Four rigid probes. See figure 2.

(c) Two fiber light bundles.

(d) Long right angle extension.

(e) 40-60 degree eyepiece extension.

(f) Magnification adapter - 2:1 magnification at 2 in. (50,8 mm).

(g) 35 mm camera adapter.

(h) Television camera adapter.

NOTE: The 35 mm camera and television camera adapters areoptional equipment and may be obtained from theborescope vendor.

(2) Preparation for use.

(a) The rigid borescope set, except for the light source, isstored in a carrying case and must be assembled prior to use.


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Rigid Borescope SetFigure 1


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Rigid Borescope Probe SpecificationsFigure 2


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CAUTION: BEFORE CONNECTING THE POWER SUPPLY TO A 110 VAC 60 HZPOWER SOURCE, BE SURE THE ON-OFF SWITCH IS IN THE OFFPOSITION AND LIGHT INTENSITY CONTROL IS SET TO MINIMUM.ENSURE PROJECTOR AND POWER SUPPLY ARE PROPERLY GROUNDED.

(b) Select desired probe. Connect the fiber bundle to the probeand to the light projector. Connect the light projectorelectrical cable to a grounded power source.

(c) When the magnification adapter is required, attach the adapterto the eyepiece at the selected probe. When used with probe 1the probe must be focused prior to attaching the magnificationadapter.

(d) If photographic record is desired, attach the 35 mm camera onthe optional adapter. Attach the camera and adapter to theeyepiece of the selected probe.

(e) When using the optional television camera adapter, attach theC-mount to the TV camera adapter and connect the cameraassembly (vidicon and low light intensifier) to the C-mount.Connect the TV camera electrical cable to the camera andcamera control unit. Attach the TV camera adapter to theeyepiece of the probe.

(f) Attach the offset eyepiece to the probe eyepiece as requiredif viewing access is limited.

(3) Operating information for the use of the rigid borescope set is asfollows:


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(a) Probe 1 is primarily used for defect assessment of thecombustion chamber and high pressure turbine (HPT) nozzle.This probe contains a variable focus adjustment in the form ofa knurled ring between the eyepiece and the fiber light bundledisconnect fitting. This is the high magnification probe andcan be used to define or access most defects in the combustionchamber or HPT nozzle. For photo recording purposes a visuallysharp focus should be obtained prior to coupling of the cameraand adapter to the borescope. Fine adjustments may then beaccomplished through adjustment of the camera adapter. Thisprobe will require more exposure time than the other probesdue to increased focal length and therefore less lighttransmission. The depth of field and field of view aredecreased because of the magnification provided in the probeoptics.

(b) Probe 2 is a general purpose 90 degree probe and is primarilyused for general inspection of the engine. Probe 2 can be usedin all borescope ports of the engine.

(c) Probe 3 is a fore-oblique angle probe primarily required forthe high pressure compressor (HPC) blade platforms andairfoils.

(d) Probe 4 is a retro-angle probe primarily required for bladetips and other liner surfaces and shrouds.

(e) Probes 2, 3 and 4 can have fixed or adjustable focus lenses.

1 For close-up inspection, less than 0.25 in. (6,4 mm) awayfrom the probe optics window, the magnification adaptershould be utilized. The magnification adapter providesvariable focus as well as magnification. The magnificationof 2 to 1 is only obtained at 2.0 in. (50,8 mm) from opticsto object distance. The magnification factor decreases forobject distances greater than 2.0 in. (50,8 mm); object tooptic spacing.


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2 For objects less than 2.0 in. (50,8 mm) from the probe lenswindow, adjust the magnification adapter to bring theobject clearly into focus. Only fine adjustments arerequired on the camera adapter. Use of the magnificationadapter for photo recording will require more exposure timefor a given probe, than photos taken without its use. Themagnification adapter is not recommended for use with probe1 during photo recording.

(f) Light projection provides the light source for the fiberbundle probes. Place the power unit switch to ON. The redindicator light should glow. Adjust the intensity of the lightsource to provide the required illumination after the probe isinserted into the engine port.

(g) Two light sources are built into the power unit. The 150-wattlamp is used for visual inspection of objects close to thedistal end of the probe. The 1000-watt high intensity lamp isused for photography as well as visual inspection ofcombustors and HPT nozzle vanes.

NOTE: The photo arc light circuit contains a thermal delaycutout that prevents the light from being turned ON iflight projector is too hot.

C. Fiberscope Set, 856A1321 and Borescope Guide Tube, 856A1310. See figure3.

(1) The flexible fiber optic system has an articulated distal tip. Thelight for viewing is conducted from the projector to the probethrough an integrally attached fiber light bundle. The distal endcan be angulated over a range of 180 degrees of arc vertically atthe bending point. The system contains the following features.


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Fiberscope SetFigure 3

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(a) Optical system specifications.

1 Distal focusing - adjustment at eyepiece.

2 Depth of field - 6 mm to 100 mm.

3 Angle of view - 90 degrees.

4 Diopter adjustment - minus 6D to plus 4D.

5 Magnification - 1:1 at 25 mm.

6 Objective focal distance - 2.13 mm.

7 Lens speed - f 2.8.

8 Image bundle size - 1.7 mm square.

9 Single fiber image guide - 17 microns.

10 Illumination - inherent light guide with 5 feet extension.

(b) Distal tip specifications.

1 Size - 6 mm dia x 20 mm long.

2 Side view - 90 degrees to centerline of probe.

(c) Bending section (articulated tip) specifications.

1 Angulation controllable at eyepiece 180° (90° up - 90°down).

2 Minimum bend radius - one in. (25,4 mm).

3 Length of bending section - 50 mm.

(d) Flexible cable-probe specifications.

1 Working length - 70 in. (1800 mm).

2 Outside diameter over working length - 6 mm.

3 Covering on cable - stainless steel braid.

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4 Temperature range - 0°F to 200°F (- 18°C to 93°C)continuous operation.

5 Light source - the fiberscope integral light bundle willattach to the Light Source Set, 856A1322.

(2) Preparation for use.

CAUTION: MOST FLEXIBLE FIBER OPTICAL SYSTEMS MAY BE DAMAGED QUITEEASILY IN VERY COLD WEATHER. FORCED BENDING OR WARMINGCAN DAMAGE THE FIBER BUNDLE. SLOWLY AND GENTLYARTICULATE TIP IN COLD WEATHER. AFTER EXPOSURE TOEXTREME COLD, WARM INSTRUMENT TO ROOM TEMPERATURE VERYGRADUALLY.

(a) Connect the fiber light bundle from probe to light projector.Connect light projector to power source. Be sure that thepower supply and power outlet is grounded.

(b) Install optional 35 mm camera adapter or TV camera adapter asrequired.

(c) Turn light projector ON.

(3) Care and use of flexible fiberscope.

The fiberscope (flexible borescope) is a precision opticalinstrument utilizing bunches of finely spun glass fibers to carrylight and images. Although guarded by a stainless steel sheath forprotection, reasonable care must be used to prevent damage andassure long service life.

(a) Read the instruction manual completely before using.

(b) Check the scope for damage before using. A slightly damagedscope, such as partial loss of tip control can result ingetting the scope hung up and finally resulting in severedamage.

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(c) Although they are safer than ones with distal tip bulbs,scopes are not explosion proof. They ~ should not be usedwhere highly volatile gases or explosive dust could reach thehot projection lamp of the external light source.

(d) Do not subject the scope to intense X-ray or gamma radiation.Glass fibers are not nonbrowning and will turn yellow, amber,or brown if exposed to radiation.

(e) When cleaning the scope, use lens tissue only on glasssurfaces. Scopes should be kept clean at all times.

(f) Avoid extreme temperatures. Use between 0°F to 200°F (- 18°Cto 93°C). Do not insert into a hot engine; heat will causebubbling of epoxy at the tip. This will cause loss of focusand damage to the lens sheath seals. Low temperatures willmake the sheath brittle and tend to crack.

(g) Hold tip or adjacent hardware when removing scope to preventdropping to floor which will avoid hard shocks.

(h) Use control knob to maneuver bending section of tip. Neverbend or twist tip by hand; damage will result.

(i) Do not force the control knob. Use the knob to guide the tipthrough curves, using tip touch to insert and also to removeor reposition the fiber probe. Do not merely push throughguide tubes nor yank out when removing.

(j) Return angle control knob to neutral position beforewithdrawing scope from engine or guide tube.

(k) Bending section is flexible in one plane only. This plane mustbe oriented to the curves in the guide tube. The plane can beestablished by the articulation control. Do not bend in a 90degree plane to the tip articulation plane.

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(l) Do not insert the scope too far into the engine. If enginerotor is rotated the tip might be cut.

(m) Use plastic guide tube, 856A1310, to guide flexible fiberscope when inspecting the leading edge of the HPT blades.

(n) When storing the scope, use care when closing the protectivecase. If the fiber bundles are closed within the case edges,damage will result. Never leave scope laying on floor where itmight be stepped on or run over.

4. Procedure Before Borescope Inspection.

A. Support Equipment.

Inspection of the HP rotor blades (compressor and turbine) requiresrotation of the core engine rotor a complete 360 degrees for each stageof blades to be inspected. This can be done manually or with the aid ofa pneumatically powered motor. A special pad is provided for thispurpose.

(1) Manual rotation.

The core engine rotor is actuated by means of a drive adapter witha long breaker bar installed into the drive pad.

(2) Pneumatic rotation.

The pneumatic turning device provides smooth even speed turning ofthe core rotor. This is an advantage to the inspector viewing theblades. Reversible control as well as speed control are providedand the need for an additional mechanic to turn the rotor iseliminated. A 360 degree protractor is integral with the device.The pneumatic pressure required is satisfied by a shop or line airsupply.

(3) Installation and operation.

The installation and operation of the MOTOR, DRIVE CORE ENGINEROTATION are given in the maintenance manual relative to eachengine model:

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Engine Tool number

CFM56-2/A/B/C 856A1142

CFM56-3 856A2002

CFM56-5/A/B/C 856A1488

CFM56-7B 856A1815

B. Zero CFM56-7B Index Position.

The zero index position is the referenced position for borescopeinspection. Thus, you can put the No. 1 blade in position before youturn each stage of blades.

(1) Low pressure rotor zero index position. See figure 4.

(a) Locate No. 1 fan blade which is identified by a circular holein the spinner rear cone adjacent to the No. 1 blade.

(b) Align the leading edge of the No. 1 fan blade with the T12temperature sensor located in the fan frame at 1: 30 o'clock,aft looking forward.

(c) The low pressure rotor is now in the zero referenced positionfor inspection.

(2) Core rotor zero index position. See figure 5.

(a) Prepare for borescope inspection.

(b) Remove the borescope port ( S4) plug between the 4 and 5o'clock position on the compressor case.

(c) Put the rigid borescope probe with the 90° right angle viewerand a 60° field of vision in the borescope port, and lock aftto the stage 4 blade platform.

(d) While you lock in the borescope, turn the core engine rotorclockwise (forward looking aft).

(e) Turn the rotor until you can see the locking lug of the firstblade slot.

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Zero Index Position of Core Engine Rotor (typical)Figure 5

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(f) Continue to turn the rotor until you see the second lockinglug. The second locking lug is 2 blades past the first lockinglug.

(g) Align the leading edge of the first blade past the secondlocking lug with the leading edge of the nearest stage 4 vane.This is the zero index point and blade number 1 for inspectionof all stages of the compressor rotor.

5. Inspection Techniques.

A. Description.

(1) The CFM56 booster has one borescope port in the stage 3 (a secondport is provided in stage 4 for CFM56-5B/5C only) for inspection.

The core rotor blade airfoils and root/platform are completelyinspectable from the gas path aspect. Borescope inspection portsare located in each HPC stator assembly. The low pressure turbine(LPT) has borescope inspection ports in all stator stages. The HPTblade leading edges are inspected using the fiberscope via theigniter ports. The relative closeness of the borescope inspectionports to the rotor blades results in high magnification viewingusing any of the specified probes (CFMI Specification M50TF3276-S1).

(2) The primary probe recommended for CFM56 inspection is probe 2, wideangle fixed field, 90 degree angle of view with 60 to 65 degreefield of view. The magnification of this probe is 1 x 1 at 2 in.(25,4 x 25,4 at 51 mm). Therefore, objects viewed closer than 2in. (51 mm) from the distal lens are magnified. Those objectsviewed further away than 2 in. (51 mm) are decreased in imagesize, relative to actual dimensions of the object. Themagnification is variable relative to blade position due to thechanging viewing distances as a rotor is turned and the bladepasses the relatively fixed borescope. The probe is turned orrotated to view the passing blade.

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Along with the varying magnification, the angle of incidence ofthe illumination beam changes as the blades pass the fixed viewingport positions. These views are further varied by probe immersionsinto the engine (radially), thus producing/providing a thirdvariable, the aspect of the object.

(3) Use a borescope probes 2, 3 or 4 change the angle of views as wellas the incidence angle of light beam relative to optic angle ofview. The magnification factor of probes 2, 3 or 4 does notchange, it is 1 x 1 at 2 in. (25,4 x 25,4 at 51 mm).

NOTE: The above factors or variables should be utilized to theinspectors advantage when attempting to assess suspecteddeterioration or defects, e.g.; scratches, cracks, contourchanges, impact results, dents, dirt smears, surface finishchanges, and coloration variables.

(4) Another helpful technique in establishing the type of defect isthrough varying the borescope light intensity. Flooding a scratch,crack, or dirt streak to attempt to establish what the mark orline really is, gives the inspector the aid of depth. Cracks thatare open do not usually disappear with low to high light levels.Dirt/carbon/water streaks do not show the depth or shadowcharacteristics that cracks exhibit. It should also be noted thatarc light sources such as the GE Marc 300/16 high intensity light(300 watt) versus the 150 watt quartz iodide or any incandescentlight source tends to give a difference in image color when viewedthrough the borescope. The 300 watt arc light gives the closest totrue or actual color of any light source.

(5) In contrast, the nonarc or incandescent light sources give a copperor bronze hue/coloration to the internal engine parts. Use of thevarious probes and variable positioning of the borescope relativeto the suspect defects usually results in defining the suspecteddefect, e.g.; a crack or dirt line or water mark, a sharp nick orsmooth dent, loss of metal or coloration change, etc. Havingestablished the defect or suspected problem, the assessment of themagnitude of the defect now becomes the challenge.

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B. Resolution Check of Borescope and Fiberscope Using Borescope ResolutionMonitor, 856A1323.

NOTE: If the person performing the testing has corrected vision, thenthe appropriate eyewear (eyeglasses, contact lenses, etc.)should be worn.

(1) Test rigid borescope as follows. See figures 6 and 7.

(a) Turn on lightsource and allow a minimum of 3 minutes warm upfor lamp to reach its' maximum operating range.

CAUTION: NEVER LOOK DIRECTLY INTO THE LIGHT BUNDLE OUTPUT.

(b) Insert male end of light bundle into lightsource. Glance atfemale end to assure that adequate light is passing through.

(c) Connect female end of light bundle to male connector onBorescope Resolution Monitor, 856A1323.

(d) Turn intensity of lightsource to maximum.

(e) Check Borescope Resolution Monitor to assure that resolutiontarget is illuminated.

(f) Insert borescope into clamping device located on arm of theBorescope Resolution Monitor, with objective window ofborescope facing resolution target.

CAUTION: DO NOT OVERTIGHTEN THE CLAMPING DEVICE. OVERTIGHTENINGCOULD RESULT IN DAMAGE TO THE BORESCOPE. HAND TIGHTENINGIS SUFFICIENT.

(g) Hand tighten borescope in place.

(h) In order to ensure that borescope is positioned correctly, layBorescope Resolution Monitor on a flat surface making surethat the arm with the clamping device is also resting on aflat surface. The objective window on borescope should be inline with black pivot bolt of arm.

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Borescope Resolution MonitorFigure 6

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Resolution TargetFigure 7 (Sheet 1 of 2)

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Resolution TargetFigure 7 (Sheet 2 of 2)

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(i) Align borescope so resolution target is centered in field ofview. If you peer through borescope and only part ofresolution target is illuminated in your field of view, (i.e.half of field of view resembles a half moon) borescope is notserviceable for engine inspection.

NOTE: The resolution target is divided into group numbers andelement numbers. There are 7 groups , with 6 elements toeach group. Group 0, element 1 is located at the lowerright of the target, its' 6 lines are quite visible toyour eye. Group 1 is located on the far right side ofthe target and appears smaller than group 0. Group 2 islocated in the center left side of the target, whilegroup 3 is located in the center right side of thetarget. Each group diminishes in size.

(j) For borescopes with a magnification of 1:1 at 2 in. (51 mm),the 6 individual lines (3 horizontal, 3 vertical) of group 3,element 4 (11.3 lines per millimeter of resolution) should bedistinguishable. Otherwise, borescope is not serviceable forengine inspection. See figure 7, sheet 1.

(k) For borescopes with a magnification of 1:1 at 7 in. (178 mm),the 6 individual lines (3 horizontal, 3 vertical) of group 5,element 2 (36.0 lines per millimeter of resolution) should bedistinguishable. Otherwise, the borescope is not serviceablefor engine inspection. See figure 7, sheet 2.

NOTE: It may be necessary to adjust the light intensity or thescope position in order to obtain the best view.However, if the forementioned group/element cannot beseen, the scope or light bundle or light source is notserviceable for engine inspection.

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(2) Test fiberscope as follows. See figures 6 and 7.

(a) Turn lightsource on and allow a minimum of 3 minutes warm upfor lamp to reach its' maximum operating range.

WARNING: NEVER LOOK DIRECTLY INTO THE LIGHT BUNDLE OUTPUT. THISCOULD RESULT IN INJURY TO PERSONNEL.

(b) Insert male end of light bundle into lightsource. Glance atfemale end to assure that adequate light is passing through.

(c) Connect female end of light bundle to male connector onBorescope Resolution Monitor, 856A1323.

(d) Turn intensity of lightsource to maximum.

(e) Check Borescope Resolution Monitor to assure that resolutiontarget is illuminated.

(f) Insert fiberscope into clamping device located on arm of theBorescope Resolution Monitor.

(g) Align objective window of fiberscope with resolution target.

CAUTION: DO NOT OVERTIGHTEN THE CLAMPING DEVICE. OVERTIGHTENINGCOULD RESULT IN DAMAGE TO THE FIBERSCOPE. HANDTIGHTENING IS SUFFICIENT.

(h) Hand tighten fiberscope in place.

NOTE: Due to the nature of the fiberscope, it may be necessaryto use a free hand to assure that the tip of theobjective window remains centered on the resolutiontarget.

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(i) Check fiberscope with objective window aligned and centered infield of view. If only part of target is illuminated in fieldof view (i.e. half of field of view resembles a half-moon),fiberscope is defective and is not serviceable for engineinspection.

NOTE: The resolution target is divided into group numbers andelements numbers. There are 7 groups, with 6 elements toeach group. Group 0, element 1 is located at the lowerright of the target, its' 6 lines are quite visible toyour eye. Group 1 is located on the far side of thetarget and appears to be smaller than group 0. Group 2is located in the center left side of the target, whilegroup 3 is located in the center right side of thetarget. Each group diminishes in size.

(j) For fiberscopes with 90° direction of view, the 6 individuallines (3 horizontal, 3 vertical) of group 1, element 4 (2.83lines per millimeter of resolution) should be distinguishable.Otherwise, the fiberscope is not serviceable for engineinspection. See figure 7, sheet 1.

NOTE: It may be necessary to adjust the light intensity or thescope position in order to obtain the best view.However, if the forementioned group/element cannot beseen, the scope or light bundle or light source is notserviceable for engine inspection.

C. Procedure.

(1) If Polaroid camera equipment and optional camera adapters areavailable, it is relatively easy to effect a comparativemeasurement.

(a) Position the rotor to obtain the best view of the defect,relative to assessment of the maintenance manual limit, e.g.;leading edge impact, tip (distortion) curl, leading edge ortrailing edge distortion, etc. Usually normal (at right angle)to the defect and centered in the field of view.

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(b) Obtain a Polaroid photo of the defect.

(c) Using a full scale cross section of the engine, for reference,locate a scale (machinist 6 in. scale marked in 0.010 in.increments) in the relative axial and circumferential positionoutside the HPC case, withdraw the borescope probe with cameraattached.

(d) Hold the borescope probe aligned with the centerline (sameposition, axial, angle of look, and circumferentialorientation as the defect photo was obtained) of the borescopeport and obtain a photo of the measurement scale.

(e) By comparative measurement, apply the magnified scaleincrements from the photo of the scale to the photo of theactual defect. These 2 photos should be at the same relativemagnification.

(2) If photographic equipment is not available, the comparativeassessment becomes more difficult; however, the followingprocedure has been used successfully.

(a) Position the rotor at the optimum rotation angle to view thedefect.

(b) Use a sample blade (if available) and mark a similar ordepiction of the blade defect. Place this blade in therelative position of the installed defective blade on theoutside of the engine.

(c) Withdraw the borescope, retaining the axial circumferentialorientation and lock angle relationship and visually assessthe comparison of the actual to marked defect (from theinstalled blade to the external sample).

(d) Re-mark or correct the depiction until satisfied that the 2images compare.

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(e) Measure the marked defect.

NOTE: A straight edge scale can also be used if no bladesamples are available to the inspector.

(3) Borescope temperature limitations.

(a) Figure 8 provides engine cool-down information relative to thevarious borescope port locations for use in determiningelapsed time required prior to engine inspection of arrivalaircraft.

(b) The information is either calculated or recorded from testengine data runs. It is not recommended that (fiber light typeor fiber optic/light flexible) fiberscope inspections beaccomplished at temperatures above 150°F (65,6°C).

CAUTION: REFER TO AIRCRAFT OPERATION MANUAL FOR STARTER DUTYCYCLE LIMITATIONS PRIOR TO MOTORING OF ENGINE.

(c) To increase the engine cool-down rate after shutdown, motorengine for a maximum of 2 minutes by utilizing the enginestarter and by carefully adhering to starter duty cyclelimitations. This will reduce the hot section area temperaturesufficiently to allow fiber optics method of inspection atthat time.

NOTE: If engine starter motoring is used it is furtherrecommended that engine hot section inspections beaccomplished within 20 minutes after the motoring cyclesare completed. Local temperature rise (due to enginetemperature soak-back) may cause local temperaturessufficient to damage the fiber optic type borescopes.

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Engine Temperature for Borescope Inspection after Engine ShutdownFollowing Normal Flight Cycle

Figure 8


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BORESCOPE INSPECTION OF LOW PRESSURE COMPRESSOR

1. Requirements.

A. On Condition Maintenance.

Borescope inspection of the booster section may be required for visualassessment check as part of the on condition engine maintenance plan.

B. Special Inspection.

Other borescope inspection checks will be required resulting fromengine problems, trend symptoms, or troubleshooting/fault isolation.The CFM56 Maintenance Manual will call out the engine sections requiredto be inspected.

2. Procedure.

The borescope inspection of the booster section is given in theMaintenance Manual or Aircraft Maintenance Manual relative to each enginemodel.

ENGINE REFERENCE

CFM56-2 72-21-00, Fan and Booster Inspection/CheckCFM56-3 TASK 72-00-00-216-008-C00CFM56-5A TASK 72-21-00-290-001CFM56-5B TASK 72-21-00-290-003CFM56-5C TASK 72-21-00-290-801CFM56-7B TASK 72-00-00-200-803-F00

3. Inspection Criteria.

A. General.

Whenever borescope inspection of the fan rotor is required, thefollowing defects must be observed and assessed as to the applicablehardware limits for serviceability. It is recommended that in-limitdefect conditions be documented for determination of subsequentdeterioration rates.

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(1) On Condition (Scheduled Inspection).

(a) Cracks or tears.

(b) Nicks and scratches.

(c) Dents.

(d) Erosion.

(e) Tip curl.

(f) Pits.

(g) Distortion leading or trailing edges.

(h) Missing metal.

(2) Special Inspections.

Specific defects accompany some of the special check requirements.The following listing relates the special checks to thoseadditional defects which are prevalent in engines havingexperienced a problem requiring special checks.

(a) Fan stall.

(b) Foreign object damage (FOD) and suspected bird injection.

(c) High fan vibs.

4. Documentation of Defects.

A. General.

(1) It is recommended that a record of the inspection be maintained foreach borescope inspection conducted. Sample forms are providedwhich include borescope inspection record forms and maps for eachrotor stage. The maps are provided so that any damage withinserviceable limits can be recorded pictorially by blade number andposition on the blade.


May 31/99

The propagation of the damage can then be pictorially illustratedduring subsequent inspections. The rotor blade maps are orientedabout the zero reference for inspection continuity. The inspectionrecords and maps will remain with the engine folder until thedamaged parts are repaired or replaced.

(2) Record inspection on inspection record. See figure 1.

B. Mapping Defects.

(1) Record individual blade damage on booster blade maps. See figure 2.

(2) Record damage detected on appropriate fan/booster rotor blade map.See figures 3 through 7. The blade numbering relative to angularposition applies only when the booster is indexed as defined insection 72-00-00.

NOTE: When defect/damage maps are used, accomplish the mapping atthe inspection site. Do not rely on memory of the defect toallow the mapping to be done in an office after theinspection. Details are lost relative to percent of chordor span, magnitude of defect, surrounding condition, etc.

C. Photo Recording of Damage.

Whenever photos are made of a defect, a record of the photo should bemade immediately on the spot. If the photo is not recorded relative toengine serial number, stage, port direction of view, and date, thecorrelation of the hardware damage and the photo will be extremelydifficult. Note directly on polaroid photos and record relative tosequence of photos on 35 mm or negative film.


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Booster Section Inspection RecordR Figure 1 (Sheet 1 of 6)

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Booster Blade MapFigure 2

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CFM56-2 Fan Rotor Map of Damaged BladesR Figure 3 (Sheet 1 of 4)

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R CFM56-7B Fan Rotor Map of Damaged BladesR Figure 3 (Sheet 4 of 4)

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R CFM56-2 Stage 2 Booster Rotor Map of Damaged BladesR Figure 4 (Sheet 1 of 6)

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R CFM56-5A Stage 2 Booster Rotor Map of Damaged BladesR Figure 4 (Sheet 3 of 6)

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R CFM56-5B Stage 2 Booster Rotor Map of Damaged BladesR Figure 4 (Sheet 4 of 6)

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R CFM56-5C Stage 2 Booster Rotor Map of Damaged BladesR Figure 4 (Sheet 5 of 6)

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R CFM56-5B Stage 5 Booster Rotor Map of Damaged BladesFigure 7 (Sheet 1 of 2)

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R CFM56-5C Stage 5 Booster Rotor Map of Damaged BladesFigure 7 (Sheet 2 of 2)

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BORESCOPE INSPECTION OF HIGH PRESSURE COMPRESSOR

1. Requirements.

A. On Condition Maintenance.

Borescope inspection of high pressure compressor (HPC) section may berequired for a visual assessment check as part of the on conditionengine maintenance.

B. Special Inspection.


2. Procedure.

The borescope inspection of high pressure compressor is given in theMaintenance Manual or Aircraft Maintenance Manual relative to each enginemodel.

ENGINE REFERENCECFM56-2 72-31-00, Maintenance PracticesCFM56-3 TASK 72-00-00-216-049-C00CFM56-5A TASK 72-31-00-290-001CFM56-5B TASK 72-31-00-290-002CFM56-5C TASK 72-31-00-290-801CFM56-7B TASK 72-00-00-200-804


A. General.

Whenever borescope inspection of the HPC is required, the followingdefects must be observed and assessed as to the applicable hardwarelimits for serviceability. It is recommended that in limit defectconditions be documented for determination of subsequent deteriorationrates.

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(1) on condition (Scheduled Inspection).

(a) Cracks.

(b) Nicks or scratches.

(c) Dents.

(d) Erosion.

(e) Tip curl.

(f) Pits.

(g) Distortion of leading or trailing edge.

(h) Missing metal.

(i) Dirt.

(2) Special inspections.

Specific defects accompany some of the special check requirements.The following listing relates the special checks to thoseadditional defects which are prevalent in engines havingexperienced a problem requiring the special check.

(a) Core stall.

(b) Oil fumes detected in cabin air.

(c) Foreign object damage (FOD).

(d) High core vibration.


A. General.

(1) It is recommended that a record of the inspection be maintained foreach borescope inspection conducted. Sample forms are providedwhich include borescope inspection record forms and maps for eachrotor stage of the compressor. The maps are provided so that anydamage within serviceable limits can be recorded pictorially byblade number and position on the blade.


May 31/99

The propagation of the damage can then be pictorially illustratedduring subsequent inspection. The rotor blade maps are orientedabout the zero reference for inspection continuity. The inspectionrecords and maps will remain with the engine folder until thedamaged parts are repaired or replaced.


B. Mapping Defects.

(1) Record individual blade damage on HPC blade map. See figure 2.

(2) Record damage detected on the appropriate compressor rotor stagemaps. See figures 3 through 11. The blade numbering relative toangular position applies only when the high pressure rotor isindexed as defined in section 72-00-00.





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Compressor Section Inspection RecordFigure 1

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Compressor Blade MapFigure 2


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Stage 1 Compressor Rotor Map of Damaged BladesFigure 3

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BORESCOPE INSPECTION OF COMBUSTION SECTION

1. Requirements.

A. On Condition.

Borescope inspection of the combustion section may be required for avisual assessment check as part of the on condition engine maintenanceplan.

B. Special Inspections.


2. Procedure.

The borescope inspection of combustion chamber is given in the MaintenanceManual or Aircraft Maintenance Manual relative to each engine model.

ENGINE REFERENCE

CFM56-2 72-42-00, Maintenance PracticesCFM56-3 TASK 72-00-00-216-023-C00CFM56-5A TASK 72-42-00-290-001CFM56-5B TASK 72-42-00-290-041CFM56-5C TASK 72-42-00-290-802CFM56-7B TASK 72-00-00-200-805-F00 (SAC)

TASK 72-00-00-200-816-F00 (DAC)


A. General.

Whenever borescope inspection of the combustion section is required,the following defects must be observed and assessed as to theapplicable hardware limits for serviceability.

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B. On Condition (Scheduled Maintenance).

(1) Discoloration.

(a) Normal aging of the combustion chamber components will show awide range of color changes. Use of arc Xenon or incandescentlight sources for borescope illumination will result in viewedcoloration differences. The closest color to true daylightviewing is gained from the use of a Marc 300/16 type hi-intensity lamp light projector. This light is close to whitelight.

(b) Use of incandescent filament lamps tend to project a yellowishcolor on the viewed hardware. Incandescent lamps usually donot have sufficient light levels to view the distant areas ofthe combustion chamber liners.

(c) Use of the Xenon arc lamp with the distal light typeborescopes tend to cast a bluish coloration on the viewedhardware. Carbon streaks have been misinterpreted as cracksand carbon deposits have bean misinterpreted as holes or burnthrough.

(2) Inner liner.

The aft panel of the inner liner is susceptable to distortion andcracking, the first evidence of this is discoloration in a roundspot approximately 1.0 in. (25 mm) dia., which is followed bydistortion and cracking. This usually occurs uniformly around theaft liner in approximately 20 places.

C. Special Inspections.

(1) Overtemperature operation.

(a) High exhaust gas temperature (EGT) increase in EGT trend.

(b) Overtemperature during takeoff or cruise.


May 31/99

(2) Impact damage observed on high pressure turbine (HPT) rotor blades.

Inspect the combustion chamber in accordance with the standardcondition check. Limits and area all apply as in an on conditioncheck.


A. General.

(1) It is recommended that a record of the inspection be maintained foreach borescope inspection conducted. Sample forms are providedwhich include borescope inspection record forms and maps for thecombustion section. The maps are provided so that any damagewithin serviceable limits can be recorded pictorially for locationof damaged area. The propagation of the damage can then bepictorially illustrated during subsequent inspections. Theinspection records and maps will remain with the engine folderuntil the damaged parts are repaired or replaced.

(2) Record inspection on single annular combustion chamber (SAC)inspection record. See figure 1.

(3) Record inspection on dual annular combustion chamber (DAC)inspection record. See figure 2.

B. Mapping Defects.

(1) Record damage on maps.

- SAC : see figures 3 through 8.

- DAC : see figures 9 through 15.

NOTE: When defect/damage maps are used, accomplish the mapping atthe inspection site. Do not rely on memory of the defect toallow the mapping to be done in an office after theinspection. Details are lost relative to magnitude ofdefect, surrounding condition, etc.

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R Single Annular Combustion Section Inspection RecordFigure 1


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R Dual Annular Combustion Section Inspection RecordR Figure 2

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R Single Angular Combustion Chamber (Typical)R Figure 3

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R Single Angular Combustion Chamber Section ViewR Figure 4


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R Outer Liner Surface Map (SAC)R Figure 5

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R Outer Liner Inner Surface Map (SAC)R Figure 6

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R Inner Liner Surface Map (SAC)R Figure 7

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R Dome Area General Map (SAC)R Figure 8

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R Dual Annular Combustion Chamber InspectionR Figure 9

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R Dual Annular Combustion Chamber InspectionR Figure 10

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R Dual Annular Combustion Chamber Borescope InspectionR Figure 11

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BORESCOPE INSPECTION OF HIGH PRESSURE TURBINE NOZZLE ASSEMBLY

1. Requirements.

A. On Condition.

Borescope inspection of the high pressure turbine (HPT) may be requiredfor a visual assessment check as part of the on condition enginemaintenance plan.


Other borescope inspection checks will be required resulting fromengine problems trend symptoms, or troubleshooting/fault isolation. TheCFM56 Maintenance Manual will call out the engine sections required tobe inspected.

2. Procedure.

The borescope inspection of high pressure turbine nozzle assembly is givenin the Maintenance Manual or Aircraft Maintenance Manual relative to eachengine model.

ENGINE REFERENCE

CFM56-2 72-51-00, Maintenance PracticesCFM56-3 TASK 72-00-00-216-023-C00CFM56-5A TASK 72-51-00-290-002CFM56-5B TASK 72-51-00-290-004CFM56-5C TASK 72-51-00-290-801CFM56-7B TASK 72-00-00-200-806-F00


A. General.

Whenever borescope inspection of the HPT nozzle assembly is required,observed defects must be assessed as to the applicable hardware limitsfor serviceability.

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B. On Condition (Scheduled Maintenance).

(1) Discoloration.

(2) Leading edge damage.

(a) Cracks.

(b) Burns.

(c) Blocked cooling air passages.

(3) Airfoil concave surface.

Cracks.

(4) Airfoil convex surface.

Cracks.

(5) Airfoil trailing edge.

(a) Cracks.

(b) Buckling and bowing.

(c) Burns.

(6) Other airfoil areas/defects.

(a) Burns.

(b) Nicks, scores, scratches, or dents.

(7) Inner and outer bands.

(a) Burns.

(b) Cracks.


May 31/99


The on condition checks pertains to all special inspection requirementsregarding hardware limits and inspection procedures.

(1) Overtemperature operation.

(2) Engine stall.

(3) Exhaust gas temperature (EGT) trend step increase.


A. General.

(1) It is recommended that a record of each inspection be maintainedfor each borescope inspection conducted. Sample forms and a map ofthe HPT nozzle assembly is provided so that any damage within (orout) of serviceable limits can be recorded. A record of the vaneby clock location as well as magnitude can be sketched on the map.This information is useful in establishing deterioration data fromsubsequent inspection or watch checks. These records shouldaccompany the HPT nozzle (module or engine) to the repair facilityfor correlation of inspection depiction versus actual hardwarecondition.



May 31/99

B. Mapping Defects.

(1) Record damage detected on the HPT nozzle vane map.See figures 2 and 3.



(1) Photos of the HPT nozzle vanes require time exposures unlessextremely fast ASA film is used. It is recommended that the probe(rigid optic fiber light borescope) be used for photo recording.This probe has the greatest fiber light transmission capability.

(2) Care should be taken to center the light beam on the vane leadingedge in question, eliminating as much glare or reflective lightingfrom the inner combustion liner. Too much immersion of the probewill show liner high-lighting and tend to wash out the HPT nozzlevane photo detail.

NOTE: Whenever photos are made of a defect, a record of the photoshould be made immediately on the spot. If the photo is notrecorded relative to engine serial number, stage, portdirection of view, and date, the correlation of the hardwaredamage and the photo will be extremely difficult. Notedirectly on polaroid photos and record relative to sequenceof photos on 35 mm or negative film.

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High Pressure Turbine Nozzle Inspection ReportFigure 1


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High Pressure Turbine Nozzle Map of Damaged Vanes (Typical)Figure 2

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R CFM56-7B HPT Nozzle Map Damaged VanesR Figure 3

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BORESCOPE INSPECTION OF HIGH PRESSURE TURBINE BLADES

1. Requirements.

A. On Condition.

Borescope inspection of the high pressure turbine (HPT) blades may berequired for a visual assessment check as part of the on conditionengine maintenance plan.


Other borescope inspection checks will be required resulting fromengine problem, trend symptoms, or troubleshooting/fault isolation. TheCFM56 Maintenance Manual will call out the engine sections required tobe inspected.

2. Procedure.

The borescope inspection of high pressure turbine blades is given in theMaintenance Manual or Aircraft Maintenance Manual relative to each enginemodel.

ENGINE REFERENCE

CFM56-2 72-52-00, Maintenance PracticesCFM56-3 TASK 72-00-00-216-026-C00CFM56-5A TASK 72-52-00-290-001CFM56-5B TASK 72-52-00-290-001-ACFM56-5C TASK 72-52-00-290-801CFM56-7B TASK 72-00-00-200-807-F00


A. General.

Whenever borescope inspections of the HPT section are required, thefollowing defects must be observed and assessed as to the applicablehardware limits for serviceability. It is recommended that in-limitdefect conditions be documented for determination of subsequentdeterioration rates.

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B. On Condition (Scheduled Inspection).

(1) Trailing edge.

Cracks.

(2) Tip area.

(a) Cracks.

(b) Bent, curled, or missing pieces.

(c) Tip trailing edge wear.

(3) Blade platform.

(a) Nicks and dents.

(b) Cracks.

(4) Concave and convex airfoil surface.

(a) Cracks.

(b) Distortion.

(c) Burning.

(5) Cooling holes.

(a) Cracks.

(b) Plugging.

C. Special Inspection.

(1) General.

Specific defects accompany some of the special check requirements.The following listing relates the special check to those typicaldefects which are prevalent in engine having experienced thoseproblems requiring the special check. In all cases, the general oncondition check should be accomplished. This section merelyhighlights those areas of distress associated with a givenproblem.


May 31/99

(2) Core stall (N2).

(a) When an engine stall is either suspected or known to haveoccurred, a borescope inspection of the HPT rotor is required;prior to release of the engine.

(b) High pressure compressor (HPC) stalls usually drive theexhaust gas temperature (EGT) to overlimit if the stall issevere or sustained. This produces tip deterioration(nibbling) on the concave or pressure face tip centered about2/3 chord aft from the leading edge.

(c) The normal on condition check must be accomplished.

(3) Overtemperature.

(a) When certain EGT excursions are reported, a borescopeinspection of HPT rotor is required; prior to release of theengine.

(b) The normal on condition check is required. The typical effectof HPT overtemperature is the nibbling of the concave orpressure face tip about 2/3 chord aft of the leading edge. Inall inspections of the HPT rotor, the on condition check andlimits apply.

(4) Metal in the tailpipe.

When metallic debris is noted in the engine tailpipe, a borescopeinspection of the HPT rotor is required; prior to release of theengine. The standard on condition check and corresponding limitsapply.

(5) N2 overspeed, core vibs, and hard landing.

An N2 overspeed, high or changing core vibration indication orfollowing a reported hard landing, will require a borescopeinspection/check of the HPT rotor prior to release of the engine.The standard on condition check and limits apply to theseconditional checks.


May 31/99


A. General.

(1) It is recommended that a record of the inspection be maintained foreach borescope inspection conducted. Sample forms are providedwhich include borescope inspection forms and maps for each rotorstage of the HPT. The maps are provided so that any damage withinserviceable limits can be recorded pictorially by blade number andposition of blade. The propagation of the damage can then bepictorially illustrated during subsequent inspections. The HPTrotor blade maps are oriented about the zero reference forinspection continuity. The inspection records and maps will remainwith the engine folder until damaged part(s) are repaired orreplaced.


B. Mapping Defects.

(1) Record individual blade damage on HPT blade map. See figure 2.

(2) Record damage detected on the appropriate high pressure turbinerotor maps. See figure 3. The blade numbering relative to angularposition applies only when the high pressure rotor is indexed asdefined in section 72-00-00.



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HPT Rotor Inspection RecordFigure 1 (Sheet 1 of 2)

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HPT Rotor Inspection RecordFigure 1 (Sheet 2 of 2)

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HPT Rotor Blade Map (Typical)Figure 2


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CFM56-2/-3 HPT Rotor Map of Damaged BladesR Figure 3 (Sheet 1 of 4)

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CFM56-5 HPT Rotor Map of Damaged BladesR Figure 3 (Sheet 2 of 4)

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R CFM56-7B With Single Annular CombustionR HPT Rotor Map of Damaged BladesR Figure 3 (Sheet 3 of 4)

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R CFM56-7B With Dual Annular CombustionR HPT Rotor Map of Damaged BladesR Figure 3 (Sheet 4 of 4)

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BORESCOPE INSPECTION OF LOW PRESSURE TURBINE

1. Requirements.

A. On Condition.

Borescope inspection of low pressure turbine (LPT) may be required fora visual assessment check as part of the on condition enginemaintenance plan.



2. Procedure.

The borescope inspection of low pressure turbine is given in theMaintenance Manual or Aircraft Maintenance Manual relative to each enginemodel.

ENGINE REFERENCE

CFM56-2 72-54-00, Inspection/CheckCFM56-3 TASK 72-00-00-216-045-C00CFM56-5A TASK 72-54-00-290-001CFM56-5B TASK 72-54-00-290-005CFM56-5C TASK 72-54-00-290-801CFM56-7B TASK 72-00-00-200-808-F00


A. General.

Whenever borescope inspections of the LPT section are required, thefollowing defects must be observed and assessed as to the applicablehardware limits for serviceability. It is recommended that in limitconditions be documented for determination of subsequent deteriorationrates.

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B. On Condition (Scheduled Inspection).

(1) Cracks in LPT rotor blades.

(a) Using the fiber light type rigid optic borescope probe 2 (wideangle scope) inspect the total airfoil, platform, and tipshrouds for evidence of cracks. For tip shroud condition, theretrograde or probe 4 is recommended. Use of the magnificationadapter is recommended for final assessment of possible orsuspect cracks in the blade tip shrouds.

(b) Cracks shall exhibit depth and under magnified assessmentshall show edge material definition. Care must be used todistinguish cracks from smears, carbon streaks, etc.

(2) Nicks and dents.

(a) Nicks and/or dents in the leading edge, trailing edge, airfoilsurfaces (convex/concave) and/or the platforms must beassessed. Note and record the presence of these defectsrelative to the percent span and percent chord for magnitudeand location on the blade. Note also the condition of theblade material adjacent (at extremities of defect) to theobserved defect. Note any cracking or sharpness of dentsand/or nicks.

(b) Smooth impact deformities to leading or trailing edge bladecontour should be noted/reported. Subsequent inspection shouldbe performed to locate the origin of such damage. For example:inspect damage to leading edge of stages 1, 2, 3 and 4 versusleading edge damage (impact) to stages 2, 3, and with minortrailing edge damage to stage 1 blades, etc.


Feb 29/96

(3) Wear.

LPT rotor blade tip shroud interlock and/or circumferential matingface area wear has been experienced. This area is viewable usingprobe 2, but if suspected wear is observed the retrograde probe 4is recommended for final assessment.

(4) Dirt, coloration, pitting, and corrosion.

High time LPT rotor assemblies may show airfoil surfaceirregularities which can be dirt accumulation, carbon buildup,pitting of the surface from particles in the gas stream orcorrosion of the blade material. These abnormalities are verydifficult to define and to differentiate between the varioussuspect defects/surface irregularities. Dirt and coloration are oflittle concern, however pitting and/or corrosion of the bladematerial are considered significant deterioration modes. Use ofall 3 probes as well as varying light intensities is required forfinal assessment of these conditions.


Special defects accompany some of the special check requirements. Thefollowing listing relates the special check to those typical defects.In all cases, the general on condition check should be accomplished.This section merely highlights those areas of distress associated witha given problem.

(1) Overtemperature inspection. See figure 1.

The LPT stage 1 and stage 4 blades (stage 5 for CFM56-5C) must beinspected.

(2) Metal in the tailpipe.

All LPT stages must be inspected.

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A. General.

(1) It is recommended that a record of the inspection be maintained foreach borescope inspection conducted. Sample forms are providedwhich include borescope inspection forms and maps for each rotorstage of the LPT. The maps are provided so that any damage withinserviceable limits can be recorded pictorially by blade number andposition of the blade. The propagation of the damage can then bepictorially illustrated during subsequent inspections. The LPTrotor blade maps are oriented about the zero reference forinspection continuity. The inspection records and maps will remainwith the engine folder until damaged part(s) are repaired orreplaced.


B. Mapping Defects.

(1) Record individual blade damage on the LPT blade map. See figure 3.

(2) Record damage detected on the appropriate LPT rotor stage map. Seefigures 4 through 8. The blade numbering relative to angularposition applies only when the low pressure rotor is indexed asdefined in section 72-00-00.

NOTE: When defect/damage maps are used, accomplish the mapping atthe inspection site. Do not rely on memory of the defect toallow the mapping to be done in an office after theinspection. Details are lost relative to percent of chordor span, magnitude of defect, surrounding condition, etc.Map the defect on the site of the inspection.

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LPT Blade Overtemperature InspectionR Figure 1 (Sheet 1 of 5)


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CFM56-2/-3 LPT Section Inspection RecordFigure 2 (Sheet 1 of 3)

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R CFM56-5A/-5B/-7B LPT Section Inspection RecordFigure 2 (Sheet 2 of 3)

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CFM56-5C LPT Section Inspection RecordFigure 2 (Sheet 3 of 3)

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LPT Blade Map (Typical)Figure 3

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CFM56-2/-3 Stage 1 LPT Rotor Map of Damaged BladesFigure 4 (Sheet 1 of 3)

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R CFM56-5A/-5B/-7B Stage 1 LPT Rotor Map of Damaged BladesFigure 4 (Sheet 2 of 3)

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CFM56-5C Stage 1 LPT Rotor Map of Damaged BladesFigure 4 (Sheet 3 of 3)

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CFM56-2/-3 Stage 4 LPT Rotor Map of Damaged Blades

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Figure 7 (Sheet 1 of 3)

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CFM56-5C Stage 5 LPT Rotor Map of Damaged BladesFigure 8

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cfm56 ndt part 7 borescope inspection

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