ORIGINAL ISSUE JUN 26/14 57-JA140140

 PAGE 1 OF 2 

SERVICE BULLETIN

BAE SYSTEMS (OPERATIONS) LIMITED, 

PRESTWICK INTERNATIONAL AIRPORT, 

AYRSHIRE, KA9 2RW, 

SCOTLAND. 

57-JA140140 

TRANSMITTAL SHEET 

This page transmits the original issue of Service Bulletin 57-JA140140. 

TITLE: WINGS - INSPECTION OF WING MAIN SPAR AROUND RIB 36 

INSPECTION 

REASON 

During fatigue testing of the wing, cracking was discovered in the wing main spar at rib 36. If the 

cracking is not detected a failure of the wing may occur. 

INSTRUCTIONS FOR INCORPORATION 

Add complete Service Bulletin pages 1 to 34 at Original Issue. 
SERVICE BULLETIN

57-JA140140 ORIGINAL ISSUE JUN 26/14 

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ORIGINAL ISSUE JUN 26/14 57-JA140140

 PAGE 1 OF 34 

SERVICE BULLETIN

BAE SYSTEMS (OPERATIONS) LIMITED, 

PRESTWICK INTERNATIONAL AIRPORT, 

AYRSHIRE, KA9 2RW, 

SCOTLAND. 

57-JA140140 

TITLE: WINGS - INSPECTION OF THE WING MAIN SPAR AROUND RIB 36 

INSPECTION 

1. PLANNING INFORMATION 

A. Effectivity 

All Jetstream 3200 Series aircraft, Post Mod JM8229. 

B. Reason 

Life extension programme requirement. 

C. Description 

The main spar inboard of rib 36 is inspected by X-ray. The main spar fasteners at rib 36 

and outboard of rib 36 are removed and a rotary eddy current inspection is performed. 

An access hole is drilled into the wing bottom skin to allow a rotary eddy current 

inspection of the underlying tooling hole in the main spar at rib 36. 

Work comprises:- 

- De-fuel the aircraft. 

- Jack and trestle the aircraft. 

- Remove wing to fuselage fairing panels and wing access panels, sufficient to allow 

removal of the rib 36 bottom external straps (2 off). 

- Remove the rib 36 bottom external straps. 

- The single row of 3/16 in. (4.7 mm) dia. countersunk fasteners inboard of rib 36 (2 

off), that pass through the main spar only, are removed and a rotary eddy current 

inspection is performed on the holes. 

- Rotary eddy current inspection is performed on the single row of 1/4 in. (6.35 mm) 

dia. fastener holes at rib 36 (2 off). 

- The 8 rows of 3/16 in. (4.7 mm) dia. countersunk fasteners outboard of rib 36 (20 off) 

that pass through the bottom skin and main spar, are removed and a rotary eddy 

current is performed on the holes. 

- The position of the rib 36 tooling hole in the main spar is located on the wing bottom 

skin. The position of the tooling hole is located using an eddy current probe. 

- A hole is drilled through the wing bottom skin to reveal the underlying tooling hole in 

the main spar at rib 36. 

- The PSR sealant within the tooling hole is cleaned out and a rotary eddy current 

inspection is performed on the tooling hole. 

- X-ray inspection is performed on the main spar inboard of rib 36. 
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57-JA140140 ORIGINAL ISSUE JUN 26/14 

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D. Manpower 

96 man-hours 

(Including 4 hours for eddy current and 3 hours to perform radiography) 

Mechanical skills are necessary. 

E. Material - Cost and Availability 

None. 

F. Weight and Balance 

Not affected. 

G. Aircraft Noise Levels 

Aircraft noise is not affected. 

H. Electrical Load Data 

Not affected. 

I. Software Accomplishment Summary 

Not applicable. 

J. References 

- Aircraft Maintenance Manual, Chapters 06, 07 and 28. 

- Non-Destructive Inspection Manual, Chapter 20. 

- Structural Repair Manual, Chapter 51. 

K. Publications Affected 

None. 

Operators are requested to advise the Business Support Team, Technical Publications, 

BAE SYSTEMS (Operations) Limited, Prestwick International Airport, Ayrshire, KA9 

2RW, SCOTLAND of the accomplishment of this service bulletin and request the 

necessary revisions for the affected manuals. 

L. Family Tree Of Modification Relationships 

Not applicable. 
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ORIGINAL ISSUE JUN 26/14 57-JA140140

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M. Approval 

The initial inspections must be performed at or before 54 000 landings. 

The inspections have to be repeated thereafter every 14 300 landings. 

The technical content of this service bulletin is to be the subject of EASA Airworthiness 

Directive consultation. 

The technical content of this service bulletin is approved under the authority of Design 

Organisation Approval No. EASA.21J.047. 
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57-JA140140 ORIGINAL ISSUE JUN 26/14 

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2. ACCOMPLISHMENT INSTRUCTIONS 

DUPLICATE INSPECTION 

WHENEVER ANY PART OF THIS SYSTEM IS DISMANTLED, ADJUSTED, REPAIRED OR 

RENEWED, DETAILED INVESTIGATION MUST BE MADE ON COMPLETION TO ENSURE 

THAT DISTORTION, TOOLS, RAGS OR ANY OTHER LOOSE ARTICLES OR FOREIGN 

MATTER SUCH AS COULD IMPEDE THE FREE MOVEMENT AND SAFE OPERATION OF 

THE SYSTEM ARE NOT PRESENT AND THAT THE SYSTEMS AND INSTALLATIONS IN 

THE WORK AREA ARE CLEAN. 

WHENEVER ANY PART OF EITHER THE MAIN OR ANY OTHER ASSOCIATED SYSTEM 

IS DISMANTLED, ADJUSTED, REPAIRED OR RENEWED, THAT PART OF THE SYSTEM 

THAT HAS BEEN DISTURBED SHALL BE SUBJECTED TO A DUPLICATE INSPECTION 

FOR SECURITY OF LOCKING DEVICES, FULL AND FREE MOVEMENT, DIRECTION AND 

TENSION CHECKS AND, FOR AIRCRAFT ON THE BRITISH REGISTER, THE 

COMPLETION OF THIS WORK SHALL BE CERTIFIED IN ACCORDANCE WITH THE 

BRITISH CIVIL AIRWORTHINESS REQUIREMENTS, SECTION A, CHAPTER A6-2 OR IN 

THE CASE OF AIRCRAFT NOT ON THE BRITISH REGISTER, THE EQUIVALENT 

NATIONAL STANDARD. 

WARNING: MAKE SURE THE AIRCRAFT AND THE AIRCRAFT SYSTEMS ARE MADE 

SAFE AS DETAILED IN THE APPLICABLE CHAPTERS OF THE AIRCRAFT 

MAINTENANCE MANUAL. 

WARNING: THE MINIMUM CLEARANCE BETWEEN MOVING AND STRUCTURAL PARTS 

MUST BE 0.2 IN (5.1 MM) UNLESS OTHERWISE STATED. 

CAUTION: TO AVOID DAMAGE, MAKE SURE BEFORE MOVING CONTROLS THAT 

CONTROL RUNS AND CONTROL SURFACES ARE FREE FROM 

OBSTRUCTION. 

CAUTION: TAKE CARE NOT TO DAMAGE STRUCTURE WHEN MATERIAL IS CUT OR 

DRILLED. REMOVE ALL UNWANTED MATERIAL FROM THE WORK AREA. 

CAUTION: IF AN ELECTRICAL CONNECTION OR CONNECTOR IS DISMANTLED, 

ASSEMBLED OR REPLACED, DO A CONTINUITY CHECK AND, IF 

APPLICABLE, A SCREEN BONDING CHECK BEFORE THE ASSEMBLY IS 

CONNECTED TO EQUIPMENT. 

NOTE: Abbreviations used in the accomplishment instructions of this service bulletin 

are: 

 AMM - Aircraft Maintenance Manual. 

 A/R - As Required. 

 FSH - Full Screen Height. 

 NDI - Non-Destructive Inspection. 

 NDT - Non-Destructive Testing. 

 SRM - Structural Repair Manual. 
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A. Preparation 

(1) Refer to AMM Chapter 12-10-28. De-fuel the aircraft. 

(2) Jack and trestle the aircraft in accordance with AMM Chapter 07-10-00. Wing 

jacks are to be located at wing Stn. 36. 

B. Accomplishment 

Inspection 

(1) Remove wing to fuselage fairing panels and wing access panels, sufficient to 

allow removal of the rib 36 bottom external straps (2 off). 

(2) Refer to Figures 1 and 2. Remove the rib 36 bottom external straps. 

NOTE: To remove the bolts through the straps, skin and main spar at rib 36 (2 off), it 

may be necessary to: 

(a) Remove the sealing block above the main spar. This may result in having to 

replace the sealing block and anchor nuts. 

(b) Drill the countersunk heads off the 2 bolts at rib 36, remove the external 

straps and remove the remaining length of bolts using a stud puller. 

(3) After removal of the external straps, re-fasten rib 36 to the bottom skin with 

temporary fasteners. 

(4) Perform a rotary eddy current inspection, in accordance with Appendix 1, on the 

single row of 1/4 in. (6.35 mm) dia. fastener holes at rib 36 (2 off). 

(5) Remove the single row of 3/16 in. (4.7 mm) dia. countersunk fasteners inboard of 

rib 36 (2 off) that pass through the main spar only. Perform a rotary eddy current 

inspection of the holes in accordance with Appendix 1. 

(6) Remove the 8 rows of 3/16 in. (4.7 mm) dia. countersunk fasteners outboard of rib 

36 (20 off) that pass through the bottom skin and main spar. Only 50% of the 

fasteners may be removed at any one time. Perform a rotary eddy current 

inspection of the holes in accordance with Appendix 1. 

(7) Refer to Figure 2. Locate the position of the underlying tooling hole in the main 

spar using the dimensions shown on Figure 2. and mark the approximate position 

on the bottom skin. This mark is intended only as a guide to where the tooling 

hole is located. 

(8) Confirm the position of the main spar underlying tooling hole using the NDT 

technique contained in Appendix 1. 

(9) Insert shim steel between the bottom skin (and doubler) and the main spar at the 

location of the tooling hole in order to protect the main spar during the drilling 

operation. If necessary, remove fasteners attaching the landing angle to the 

bottom skin (and doubler). 
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ORIGINAL ISSUE JUN 26/14 57-JA140140

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(10) Drill a 1/8 in. (3.2 mm.) dia. hole in the bottom skin (and doubler) at the location of 

the tooling hole. Remove the shim steel and check the proximity of the drilled hole 

to the underlying tooling hole. Gradually increase the dia. of the drilled hole to 

align the centre of the drilled hole with the centre of the tooling hole. The final dia. 

of the drilled hole should be 1/4 in. (6.35 mm.) dia. to match the dia. of the tooling 

hole. Oversizing the drilled hole in the skin and doubler up to 3/8 in. is permitted if 

required to align the drilled hole with the tooling hole. Oversizing above 0.25 in. 

must be reported to BAE SYSTEMS before proceeding. 

(11) Drill out and remove the PSR sealant within the tooling hole. 

(12) Perform a rotary eddy current inspection of the tooling hole in accordance with 

Appendix 1. 

(13) Apply brush Alocrom 1200, in accordance with SRM 51-30-63, to any bare metal 

within the tooling hole and the drilled hole in the skin and doubler. 

(14) Apply Epoxy Primer, in accordance with SRM 51-30-66, to any bare metal within 

the tooling hole and the drilled hole in the skin and doubler. 

(15) Fill the tooling hole and the drilled hole in the skin and doubler using PR1422 or 

PR1782 sealant. 

(16) Perform X-ray inspection of the main spar inboard rib 36 in accordance with 

Appendix 2. 

(17) Any defects observed during the above inspections must be reported to BAE 

Systems before proceeding. 

NOTE: Appendix 2 can be performed before, during or after the removal of the 

external straps at rib 36. 

C. Recovery 

(1) Replace the external straps, sealing block (if required) and all removed fasteners 

with new or serviceable items (for fastener details refer to Drawing No’s. 

1379149B and 1379209B). Wet assemble in accordance with SRM 51-50-10. 

(2) Any over-sizing of fastener holes must be reported to BAE Systems before 

proceeding. 

(3) Replace all removed fairings and access panels.

(4) Make certain work area is clean, and clear of tools and miscellaneous equipment. 

(5) Refer to AMM Chapter 07-10-00. Remove jacks and trestles and lower aircraft. 

(6) Close up. 

(7) Aircraft records: 

(a) Add service bulletin number 57-JA140140 to the aircraft records. 
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(b) Add Mod JM8230 to the aircraft records. 

NOTE: Operators are reminded of the necessity to inform the Business Support Team, 

Technical Publications, BAE Systems (Operations) Limited, Prestwick 

International Airport, Ayrshire, KA9 2RW, SCOTLAND, of the accomplishment 

of this service bulletin in order to obtain the necessary revisions for the affected 

manuals, see paragraph 1.K. Publications Affected, of this service bulletin. 
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ORIGINAL ISSUE JUN 26/14 57-JA140140

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3. MATERIAL INFORMATION 

NOTE: The following material data is provided on a 'per' aircraft basis. Use the applicable 

material kit number shown to order the parts required. 

A. New parts supplied as material kit 

None. 

B. Replacement Parts - Operators Supply 

Part No. Description 1

st Oversize 

(1/64) 

2

nd Oversize 

(1/32) 

Qty 

(Req’d 

per a/c) 

Comment 

PR1422 or PR1782 Sealant - - As 

required - 

 1379170B401 Sealing Block - - 1 - 

 1379170B402 Sealing Block - - 1 - 

 MS21059L5 Anchor Nut - - 4 - 

 NAS7403-6 Bolt - CSK NAS7403-6X NAS7403-6Y 14 - 

 NAS7403-7 Bolt - CSK NAS7403-7X NAS7403-7Y 10 - 

 NAS7403-8 Bolt - CSK NAS7403-8X NAS7403-8Y 8 - 

 NAS7403-30 Bolt - CSK NAS7403-30X NAS7403-30Y 6 - 

 NAS7403-31 Bolt - CSK NAS7403-31X NAS7403-31Y 10 -

 NAS7403-32 Bolt - CSK NAS7403-32X NAS7403-32Y 16 -

 NAS7403-34 Bolt - CSK NAS7403-34X NAS7403-34Y 8 - 

 NAS7404-8 Bolt - CSK NAS7404-8X NAS7404-8Y 18 - 

 NAS7404-10 Bolt - CSK NAS7404-10X NAS7404-10Y 2 - 

 NAS7404-11 Bolt - CSK NAS7404-11X NAS7404-11Y 8 - 

 NAS7404-12 Bolt - CSK NAS7404-12X NAS7404-12Y 6 - 

 NAS7404-13 Bolt - CSK NAS7404-13X NAS7404-13Y 14 -

 NAS7404-14 Bolt - CSK NAS7404-14X NAS7404-14Y 12 -

 NAS7404-45 Bolt - CSK NAS7404-45X NAS7404-45Y 4 - 

NAS7405-45 Bolt - CSK NAS7405-45X NAS7405-45Y 4 

Oversize may 

be required at 

this position 

 AS8600-D Nut N/A N/A 72 

 AS8600-E Nut N/A N/A 60 

 SP124-D Washer N/A N/A 72 

 SP124-E Washer N/A N/A 60 

 SP71-608 Rivet - CSK N/A N/A 8 
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Wing Main Spar Around Rib 36 

Figure 1 
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Area of Inspection Around Rib 36 

Figure 2 
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APPENDIX 1 

EDDY CURRENT INSPECTION INSTRUCTION 

Examination of the Wing Main Spar Lower Boom and Slab at Rib 36 

A. Instruction Reference 

(1) None. 

B. Safety Precautions 

(1) For the relevant safety precautions refer to NDT Manual, Part 1, 

Chapter 20-00-00, Paragraph 3. 

C. Procedure 

(1) Application 

(a) This instruction is to be applied to all BAe Jetstream 32 aircraft at the 

intervals defined in the relevant Service Bulletin or Maintenance Document. 

(2) Component to be examined 

(a) Wing main spar lower boom and slab, left and right (refer to Figures 3 and 

4). 

(3) Area of examination 

(a) Tooling hole under rib 36 and adjacent fastener positions (refer to Figures 3 

and 4). 

(4) Purpose of examination 

(a) Part A – Low frequency eddy current inspection

 The low frequency, phase analysis, eddy current inspection is applied to 

locate and mark the position of the tooling hole on the wing lower skin. The 

marked position of the tooling hole facilitates the drilling operation, through 

the lower skin and doubler, to uncover the tooling hole for further inspection. 

(b) Part B – Rotary eddy current inspection 

 The rotary phase analysis, eddy current inspection inspects the tooling hole 

and adjacent fastener holes for fatigue cracks, 0.050 in. (1.27 mm) in length, 

or greater, which initiate in the hole bores and propagate fore and aft. 
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(5) Equipment required 

(a) The following equipment was used during the development of this inspection 

instruction and was found to be acceptable. 

Part A – Low Frequency Eddy Current Inspection 

(1) Instrument: Elotest B1 v4 phase analysis eddy current instrument 

with B1-RS adapter, from Rohmann (UK) Ltd. 

(2) Probe: Reflection, part number RR207-5/4F, 500 Hz. – 20 

kHz, from Olympus NDT. (Ref. Fig. 5) 

(3) Lead: Part number EK-2-HF/1 from Rohmann (UK) Ltd. 

(4) Reference 

standard: 

Part number SSI 57-10-227/1 (Ref. Figs. 5, 6 and 7)

Part B – Rotary Eddy Current Inspection 

(1) Instrument: Elotest B1 v4 phase analysis eddy current instrument 

with B1-RS adapter, from Rohmann (UK) Ltd. 

(2) Rotor: Mini-rotor attachment for Elotest B1, reference 

number MR3, from Rohmann (UK) Ltd. 

(3) Probe 1: 3/16 in. (4.7 mm) dia., 4 in. (50.8 mm) working length, 

part number MRRP-RUK-1-3/16-4 in., from Rohmann 

(UK) Ltd. 

(4) Probe 2: 0.25 in. (6.35 mm) dia., 4 in. (50.8 mm) working 

length, part number MRRP-RUK-1-0.25-4 in., from 

Rohmann (UK) Ltd. 

(5) Lead: Part number, RK-2-N/1, from Rohmann (UK) Ltd. 

(6) Calibration 

standard: 

Aluminium calibration block for rotary (dynamic) eddy 

current testing, cross-drilled hole type (Ref. NTM Part 

6, 20-00-00) 

NOTE: Any comparable eddy current equipment may be used provided it satisfies 

the requirements of this instruction and is capable of resolving the tooling 

hole and the 1/16 in. (1.58 mm) dia. hole in the calibration standards at the 

required level of sensitivity. 

(6) Preparation 

(a) Refer to Para’s. 2.A. and 2.B. 
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(7) Component 

(a) To accomplish Part B ensure drilling operation has been carried out and the 

tooling hole is accessible for inspection. 

(b) Tooling hole and bolt hole bores must be clean and free from burrs. 

(c) Visually check the inspection areas for damage prior to inspection. 

(8) Examination procedure 

Part A – Low Frequency Eddy Current Inspection 

Initial settings: Refer to manufacturer’s instructions. 

Alarm: Optional – Refer to manufacturer’s instructions. 

Frequency: Set to 1 kHz. 

Gain: Set to produce required sensitivity. 

 Pre-amp: 10 dB. 

 Y spread: 20 dB. 

 X spread: 0 dB. 

Filter: Band: Set to Static. 

 High pass: Set to Off. 

 Low pass: Set to 10 Hz. 

Bandwith limiter: Set to On. 

Timebase/Display: Y/X. 

Dot position Reference Fig. 5. 

(9) Sensitivity setting (Ref. Fig. 5) 

(a) Place the probe on the surface of the calibration standard away from the 

sub-surface hole and balance the instrument. 

(b) Set lift-off effect to horizontal and to the left. 

(c) Slide the probe over the sub-surface hole and note the response. Adjust the 

instrument settings to obtain a maximum signal from the hole of 50 per cent 

Full Scale Height (FSH). 
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Approaching the hole from any direction will cause the spot to rise as the probe 

recognises the edge of the hole, however as the probe centralises over the hole 

the spot will fall. The spots lowest position will indicate the precise centre of the 

hole. Approach from various directions to ensure accuracy. 

(10) Inspection procedure (Ref. Fig. 4) 

(a) Place the probe on the wing lower skin directly under rib 36 and balance the 

instrument. 

(b) Search the area in the anticipated position of the tooling hole (Ref. Fig 2) 

and identify the sub-surface hole. 

(c) Centralise the probe over the hole applying the search techniques used 

during calibration. 

(d) Accurately mark the probe centre to provide centre for the drilling operation. 

Part B – Rotary Eddy Current Inspection 

Initial settings: Refer to manufacturer’s instructions. 

Alarm: Render inoperative. 

Frequency: Set to 500 kHz. 

Gain: Set to produce required sensitivity. 

 Pre-amp: 30 dB. 

 Y spread: 0 dB. 

 X spread: 0 dB. 

Filter: Band: Set to Dynamic. 

 High pass: Set to 500 Hz. 

 Low pass: Set to 2.5 Hz. 

Bandwidth limiter: Set to On. 

(11) Sensitivity settings (Ref. Fig. 8) 

(a) Select spot (Y/X) display. 

(b) Adjust the instrument to produce a vertical signal from the 1/16 in. (1.58 

mm) dia. cross-drilled hole in the rotary calibration block. 

(c) Select timebase (Y/T) display. 
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(d) Set signal from cross-drilled hole to 100 per cent FSH. 

(e) Select spot (Y/X) display. 

(f) Set signal from cross-drilled hole to 30 deg. anti-clockwise. 

(g) For each dia. probe used, repeat operations (a) to (f) prior to inspection. 

(12) Inspection procedure (Ref. Fig. 4). 

(a) Select spot (Y/X) display. 

(b) Scan the full length of the tooling hole and two adjacent fastener holes 0.25 

in. (6.35 mm), three positions per side. 

(c) Scan the full length of the 3/16 in. (4.7 mm) dia. fastener holes, twenty 

positions per side. 

(d) By careful manipulation maximise any signals. 

(13) Acceptance criteria 

Part A – Low Frequency Eddy Current Inspection 

(a) Interpretation 

(1) Interpret signals (Ref. Fig. 5). 

(b) Accept/Reject criteria 

(1) Accurately mark probe centre to provide centre for drilling operation. 

Part B – Rotary Eddy Current Inspection 

(a) Interpretation 

(1) Interpret signals (Ref. Fig. 9). 

(2) Select timebase (Y/T) display to ascertain the amplitude and direction of 

each signal. 

(b) Accept/Reject criteria 

(1) Vertical signals over 20 per cent FSH that cannot be attributed to probe 

handing or material interfaces shall be considered as a crack. 

(2) All other signals over 40 per cent FSH, irrespective of angle, that cannot 

be attributed to probe handling or material interfaces shall be 

considered as a discontinuity. 

NOTE: The word discontinuity is a generic term for faults such as cracks, 

corrosion and mechanical damage. 
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(14) Examination standard 

 (a) All cracks and discontinuities are to be recorded in the relevant 

aircraft documentation and the appropriate BAE SYSTEMS approved 

repair/rectification action taken. 

(15) Reporting procedure 

 (a) Report all crack/discontinuities on Operator Report Form. 

 (b) Also include: 

(1) Aircraft constructor’s number. 

(2) Aircraft registration. 

(3) Flying hours/landings. 

(4) SB number. 

(5) Component/serial number. 

(6) Location/length of crack or discontinuity/signal amplitude per 

cent FSH. 

(16) Additional information 

(a) Related documents. 

(1) NDI Manual, Part 6, Chapter 20-00-00, Eddy Current Inspection, 

General. 

(2) Test equipment manufacturer’s handbook. 
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Area of Inspection – Main Spar Lower Boom at Rib 36

Figure 3 
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Main Spar - Inspection 

Figure 4 
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Instrument Calibration and Probe Details 

Figure 5 
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Calibration Standard Part Number 57-10-227/1 – Material Details 

Figure 6 
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Calibration Standard Part Number 57-10-227/1 – Hole Details 

Figure 7 
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Typical Screen Display – Rotary (Dynamic) Eddy Currents 

Figure 8 
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Spot (Y-X) Display Showing Signal Angles 

Figure 9 
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APPENDIX 2 

RADIOGRAPHIC INSTRUCTION 

Examination of the Wing Main Spar Boom and Slab Inboard of Rib 36 

A. Instruction Reference 

(1) None. 

B. Safety Precautions 

(1) For the relevant safety precautions refer to NDT Manual, Part 1, 

Chapter 20-00-00, Paragraph 3. 

C. Procedure 

(1) Application 

(a) This instruction is to be applied to all BAe Jetstream 32 aircraft at the 

intervals defined in the relevant Service Bulletin or Maintenance Document. 

(2) Component to be examined 

(a) Wing main spar lower boom and slab, inboard of rib 36, left and right (Ref 

Fig. 10). 

(3) Area of examination 

(a) Fastener holes adjacent inboard of rib 36. 

(4) Purpose of examination 

(a) The inspection is intended to detect fatigue cracks which initiate in the 

fastener holes and propagate fore and aft. 

(5) Equipment and materials required 

The following equipment was used during the development of this inspection 

instruction and was found acceptable. 

(a) Seifert Eresco MF2 200CP X-ray set. Focal spot size 0.059 in. x 0.059 in. 

(1.5 mm x 1.5 mm). 

(b) Film – Fuji IX 100 (for details refer to Table 1). 

NOTE: Any comparable X-ray equipment and materials may be used provided 

they satisfy the requirements of this instruction (The focal spot size must 

not exceed that detailed in Paragraph 5.(a)). 
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(6) Preparation for inspection 

(a) Refer to Para’s. 2.A. and 2.B: 

(b) Component 

(1) Ensure that sealant is removed from the rib 36 to main spar 

intersection. This must be done thoroughly to ensure that the film can 

be placed in close contact with the front spar and rib 36. Reinstate 

sealant in accordance with the SRM on completion of the inspection. 

(7) Examination procedure 

(a) Film details 

Table 1. 

Type Size (in.) Size (cm) Quantity per 

aircraft 

FUJI IX 100 Ref. Fig. 11 Ref. Fig. 11 6 

NOTE: FUJI IX 100 film was used for this inspection, but other manufacturer’s 

fine grain, medium speed film may be substituted. 

(8) Film identification 

(a) Unique reference number traceable to the specific inspection details. 

(b) Film number. 

(c) Film location and orientation, such as side and direction. 

(9) Film location 

(a) Film is located as shown in Figures 10 and 11. Film should be hard against 

rib 36 and the main spar web. 

(10) Tube head location 

(a) The X-ray tube head is located directly beneath and normal to the main spar 

(Ref. Fig. 10). 

 (11) Exposure details 

(a) Expose films as detailed in Figures 10 and 12. 

(12) Interpretation 

(a) Cracks typically appear as more dense linear indications. 
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(b) Corrosion typically appears as more dense areas or individual spots 

irregular in shape with poorly defined extremities. It is generally agreed that 

corrosion of less than 10 per cent in depth of the total thickness penetrated 

by the X-ray beam will not be readily detected by conventional radiographic 

methods. 

(13) Accept/Reject criteria 

(a) Any crack like indication, material loss/corrosion or obvious damage is to be 

reported in the appropriate aircraft documentation and the appropriate 

approved repair/rectification action taken. 

(14) Reporting procedure 

 (a) Report all crack/discontinuities on Operator Report Form. 

 (b) Also include: 

(1) Aircraft constructor’s number. 

(2) Aircraft registration. 

(3) Flying hours/landings. 

(4) SB number. 

(5) Left or right wing. 

(6) Position, direction and length of crack or discontinuity/ per cent 

FSH. 

(15) Additional information 

(a) Ensure all test equipment is removed from the aircraft on completion 

of work. 
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ORIGINAL ISSUE JUN 26/14 57-JA140140

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Area of Inspection – Wing Main Spar Lower Boom and Slab 

Figure 10 
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Film Sizes and Positioning 

Figure 11 
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Exposure Details Sheet 

Figure 12 
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OPERATOR REPORT FORM 

This Operator Report Form is required to be completed and returned to: 

BAE SYSTEMS Regional Aircraft, 

Repair Design Office, 

Building 37, 

Prestwick International Airport, 

Ayrshire, KA9 2RW, 

SCOTLAND. 

Tel No. +44 (0) 1292 67 5276. 

Fax No. 01292 675432. 

Title Wing – Inspection of Wing Main Spar Around Rib 36. 

Service Bulletin 

No. 

Operator Aircraft 

Registration 

No. 

Aircraft 

Constructors 

No. 

Flying Hours No. of 

landings 

57-JA140140. 

Initial Issue 

 

Description of inspection results, include all marked up figures and sketches: