Service Bulletin

Fokker 70/100

Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

Revision - - - - - - - - - - - - - - - - -

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Revision - - - - - - - - - -

Jun 16/11 SBF100-53-115

Page 1

Copyright All rights reserved by Fokker Services B.V. (The Netherlands). This document has been supplied by Fokker Services B.V. to its customers on a confidential basis subject to the provisions of an agreement. 

Reproduction or disclosure to third parties of this document or any part thereof, or the use of any information contained therein for purposes other than explicitly allowed by the aforesaid agreement, is not permitted 

except with the prior written permission of Fokker Services B.V.

FUSELAGE

 Forward Fuselage - The Repetitive External Inspection and Temporary Repair of the Butt Joints

at Stringers 12 and 61 between Stations 3850 and 5305.

1. Planning Information

A. Effectivity

(1) F28 Mark 0070/0100 aircraft serial numbers:

11268 thru 11283, 11286, 11289, 11291, 11293, 11295, 11300, 11303, 11306, 

11308, 11310, 11312 thru 11314, 11316, 11318, 11321, 11323 thru 11335, 11337, 

11338, 11340, 11345, 11346, 11349, 11352 thru 11361, 11365 thru 11370, 11372, 

11373, 11376 thru 11380, 11387, 11388, 11391, 11392, 11395 thru 11399, 

11403 thru 11408, 11411 thru 11419, 11425 thru 11428, 11432, 11435, 11436, 

11438, 11439, 11444 thru 11450, 11456 thru 11460, 11464 thru 11469, 

11475 thru 11479, 11481 thru 11506, 11509, 11511 and 11513 thru 11585.

B. Concurrent Requirements

(1) Not applicable.

C. Reason

(1) A crack was reported at a butt joint on the forward fuselage underneath the 

passenger door. Investigation revealed that, depending on the configuration of the 

aircraft, one or two butt joints in the forward fuselage are critical and a repetitive 

inspection is required.

(2) When crack indications are found the applicable butt joint has to be repaired before 

further flight.
Service Bulletin

Fokker 70/100

SBF100-53-115 Jun 16/11

Page 2

Copyright All rights reserved by Fokker Services B.V. (The Netherlands). This document has been supplied by Fokker Services B.V. to its customers on a confidential basis subject to the provisions of an agreement. 

Reproduction or disclosure to third parties of this document or any part thereof, or the use of any information contained therein for purposes other than explicitly allowed by the aforesaid agreement, is not permitted 

except with the prior written permission of Fokker Services B.V.

D. Description

(1) This Service Bulletin is divided in 4 Parts as follows:

Part 1: The Manufacturing of the Calibration Plate for the Inspection.

This Part tells how to:

- Manufacture the calibration plate for the inspection according Parts 1 and 2.

Part 2: The Repetitive External Inspection of the Butt Joint at Stringer 12 between 

Stations 3850 and 5305 (Applicable to F28 Mark 0100 Aircraft Serial 

Numbers 11268 thru 11283, 11286, 11289, 11291, 11293, 11295, 11300, 

11303, 11306, 11308, 11310, 11312 thru 11314, 11316, 11318, 11321, 

11323 thru 11335, 11337, 11338, 11340, 11345, 11346, 11349, 

11352 thru 11361, 11365 thru 11370, 11372, 11373, 11376 thru 11380, 

11387, 11388, 11391, 11392, 11395 thru 11399, 11403 thru 11408, 11411 

thru 11417, 11419, 11425 thru 11428, 11432, 11435, 11436, 11438, 11439, 

11444 thru 11450, 11456 thru 11460, 11464 thru 11469, 11475 thru 11479, 

11481 thru 11487, 11490 thru 11495, 11498, 11499, 11501, 11502, 11504, 

11506, 11513 thru 11515, 11519, 11520, 11522 and 11523).

NOTE: This Part is not applicable to aircraft serial number 11418, because this 

aircraft has already been permanently repaired/modified (similar to the 

terminating repair/modification according SBF100-53-116).

This Part tells how to:

- Carry out the external inspection of the butt joint at stringer 12, below the forward 

opening passenger door, using Low Frequency Eddy Current (LFEC).

Part 3: The Repetitive External Inspection of the Butt Joint at Stringer 61 between 

Stations 3850 and 5305 (Applicable to all aircraft listed in the paragraph 1.A. 

Effectivity).

This Part tells how to:

- Carry out the external inspection of the butt joint at stringer 61, below the forward 

service/emergency door, using Low Frequency Eddy Current (LFEC).

Part 4: The Temporary Repair of the Butt Joint(s).

This Part tells how to:

- Install a temporary repair when crack indications are found.

E. Compliance

(1) Fokker Services recommends the accomplishment of Part 2 and 3 of this Service 

Bulletin at the following times:

The first inspection has to be carried out before the aircraft exceeds a total number of 

20 000 flight cycles (FC) or within 180 flight cycles (FC) after the date of issue of this 

Service Bulletin, whichever comes later. The inspections must be repeated at 

intervals not exceeding 1 000 flight cycles (FC).
Service Bulletin

Fokker 70/100

Jun 16/11 SBF100-53-115

Page 3

Copyright All rights reserved by Fokker Services B.V. (The Netherlands). This document has been supplied by Fokker Services B.V. to its customers on a confidential basis subject to the provisions of an agreement. 

Reproduction or disclosure to third parties of this document or any part thereof, or the use of any information contained therein for purposes other than explicitly allowed by the aforesaid agreement, is not permitted 

except with the prior written permission of Fokker Services B.V.

NOTE 1: An alternative inspection method is a visual Detailed Inspection of the butt 

joint(s) from the inside. Only note that to gain access to the inspection area 

from the inside several components must be removed and after the 

inspection has been performed all components that are removed must be 

reinstalled and tested, all in accordance with the applicable AMM 

procedures.

NOTE 2: It is expected that EASA will issue an Airworthiness Directive (AD) with 

respect to this subject with the same compliance terms. Refer to the EASA 

website for the publication of the Airworthiness Directive.

NOTE 3: As a precautionary measure the temporary repair can be performed on 

each frame bay, even without crack findings. These temporary repairs will 

in the end have to be replaced by a terminating repair/modification 

(SBF100-53-116). The current expectation is that the temporary repairs

have to be replaced within 10 000 flight cycles (FC). However final actions 

as mentioned in NOTE 4 may require an earlier replacement.

When the temporary repair has been performed on one or more frame 

bays, these frame bays no longer require the repetitive inspection.

NOTE 4: This Service Bulletin covers the interim actions required to assure 

continued airworthiness. Final action (superseding and cancelling this SB) 

will likely be covered by a task in the ALI-section (report SE-623) of the 

Maintenance Review Board (MRB) document and a terminating 

repair/modification as mentioned under NOTE 3.

F. Approval

(1) The technical content of this document is approved under the authority of DOA nr. 

EASA.21J.059.

G. Manpower

(1) Approximately 2 man-hours are necessary to manufacture the special inspection 

calibration tool according Part 1 of this Service Bulletin.

This table of manpower will help you to schedule and do this Part:

Instructions Men Man-hours Elapsed time

(hours)

Manufacturing 1 2,0 2,0

Total 2,0 2,0

NOTE: This estimate does not include the time necessary for the sealant to cure.
Service Bulletin

Fokker 70/100

SBF100-53-115 Jun 16/11

Page 4

Copyright All rights reserved by Fokker Services B.V. (The Netherlands). This document has been supplied by Fokker Services B.V. to its customers on a confidential basis subject to the provisions of an agreement. 

Reproduction or disclosure to third parties of this document or any part thereof, or the use of any information contained therein for purposes other than explicitly allowed by the aforesaid agreement, is not permitted 

except with the prior written permission of Fokker Services B.V.

(2) Approximately 1 man-hour is necessary to do Part 2 of this Service Bulletin on one 

aircraft.

This table of manpower will help you to schedule and do this Part:

Instructions Men Man-hours Elapsed time

(hours)

Removal - - -

Modification

Inspection 1 1,0 1,0

Installation - - -

Testing - - -

Total 1,0 1,0

(3) Approximately 1 man-hour is necessary to do Part 3 of this Service Bulletin on one 

aircraft.

This table of manpower will help you to schedule and do this Part:

Instructions Men Man-hours Elapsed time

(hours)

Removal - - -

Modification

Inspection 1 1,0 1,0

Installation - - -

Testing - - -

Total 1,0 1,0

(4) Approximately 40 man-hours are necessary to do Part 4 of this Service Bulletin on 

one aircraft.

This table of manpower will help you to schedule and do this Part:

Instructions Men Man-hours Elapsed time

(hours)

Removal - - -

Modification

Inspection 2 40,0 20,0

Installation - - -

Testing - - -

Total 40,0 20,0

NOTE 1:This estimate is based on the temporary repair of all eight frame bays. If only 

one frame bay is repaired approximately 4-6 man-hours are necessary.

NOTE 2:This estimate does not include the time necessary for the paint to dry and/or 

the sealant to cure.

(5) The estimated hours are for direct labor done by experienced personnel. They are 

calculated based on the conditions given in SBF100-00-001 (Service Bulletin 

Introduction, section 2.C., "Manpower").
Service Bulletin

Fokker 70/100

Jun 16/11 SBF100-53-115

Page 5

Copyright All rights reserved by Fokker Services B.V. (The Netherlands). This document has been supplied by Fokker Services B.V. to its customers on a confidential basis subject to the provisions of an agreement. 

Reproduction or disclosure to third parties of this document or any part thereof, or the use of any information contained therein for purposes other than explicitly allowed by the aforesaid agreement, is not permitted 

except with the prior written permission of Fokker Services B.V.

H. Weight and Balance

(1) Part 4:

(a) Repair accomplished on one side between sta 3850-4175:

1 Weight change: + 0,08 kg (0.177 lb)

Index change: Mark 0100: - 0.011

Mark 0070: - 0.009.

(b) Repair accomplished on one side between sta 4175-4610:

1 Weight change: + 0,15 kg (0.324 lb)

Index change: Mark 0100: - 0.019

Mark 0070: - 0.015.

(c) Repair accomplished on one side between sta 4610-4850:

1 Weight change: + 0,07 kg (0.149 lb)

Index change: Mark 0100: - 0.008

Mark 0070: - 0.007.

(d) Repair accomplished on one side between sta 4850-5305:

1 Weight change: + 0,14 kg (0.305 lb)

Index change: Mark 0100: - 0.017

Mark 0070: - 0.014.

I. Electrical Load Data

(1) Not changed.

J. Software Accomplishment Summary

(1) Not applicable.

K. References

(1) Fokker 70/100 Structural Repair Manual (SRM)

Fokker 70/100 Aircraft Maintenance Manual (AMM)

Fokker 70/100 Maintenance Review Board (MRB) document

Fokker 70/100 Maintenance Planning Document (MPD)

Fokker 70/100 Service Bulletin:

- SBF100-53-116

Fokker Consumable Material List (CML)

Fokker internal reference(s):

- ECR015780.
Service Bulletin

Fokker 70/100

SBF100-53-115 Jun 16/11

Page 6

Copyright All rights reserved by Fokker Services B.V. (The Netherlands). This document has been supplied by Fokker Services B.V. to its customers on a confidential basis subject to the provisions of an agreement. 

Reproduction or disclosure to third parties of this document or any part thereof, or the use of any information contained therein for purposes other than explicitly allowed by the aforesaid agreement, is not permitted 

except with the prior written permission of Fokker Services B.V.

L. Publications Affected

(1) This SB affects the publications listed below:

(a) Maintenance Documentation

Not affected.

(b) Maintenance Programs

- Fokker 70/100 Maintenance Review Board (MRB)

- Fokker 70/100 Maintenance Planning Document (MPD)

(c) Special Instructions for Continued Airworthiness (ICA)

The effect of this Service Bulletin on the special ICA is as follows:

YES NO

- Electrical Wiring Interconnection System (EWIS) - X

- Fuel Tank Safety (FTS) - X

- Damage Tolerance of Fatigue Critical Structure X -

NOTE: If “YES”, when not already incorporated, the changed ICA will be 

incorporated in the MRB document within one calendar year from the 

date of issue of this Service Bulletin. Until then, no actions are required.

(d) Operational Documentation

Not affected.

(2) Report to Fokker Services that this SB has been carried out on the applicable aircraft.

Send to Fokker Services the “Reporting Quality Form” of this SB. Refer to the last 

page of this SB.

(3) For incorporation of this Service Bulletin in your documentation refer to 

SBF100-00-001 (Service Bulletin Introduction, section 4 "Incorporation of Service 

Bulletins in Documentation of Fokker Services").

M. Interchangeability or Intermixability of Parts

(1) Not applicable.
Service Bulletin

Fokker 70/100

Jun 16/11 SBF100-53-115

Page 7

Copyright All rights reserved by Fokker Services B.V. (The Netherlands). This document has been supplied by Fokker Services B.V. to its customers on a confidential basis subject to the provisions of an agreement. 

Reproduction or disclosure to third parties of this document or any part thereof, or the use of any information contained therein for purposes other than explicitly allowed by the aforesaid agreement, is not permitted 

except with the prior written permission of Fokker Services B.V.

2. Material Information

A. Material – Price and Availability

(1) The materials are local source items.

B. Material Required

(1) These parts, which are necessary to complete Part 1 and/or Part 4 of this Service 

Bulletin on 1 aircraft, are not part of the mod kit.

New Part Number Qty Keyword Info Old Part Instructions/

*

1

*

2 Number Disposition

Alodine1201 - AR* Coating Fk13-003D** - Local source

F0N1-4311-1AP- *

3 AR* AR* Sheet, aluminum 2024T3 Alclad - Local source

F0N1-4311-2AD- *

4 AR* - Sheet, aluminum 2024T3 Alclad - Local source

F0N2-6395B5xx - AR* CSK blind rivet CR3222-5-xx - Local source

F0N2-6397B6xx - AR* CSK blind rivet CR3224-6-xx - Local source

F0N18-9151S05 - AR* CSK repair washer - - Local source

F0N18-9151S06 - AR* CSK repair washer - - Local source

PR1436GA1-2 AR* AR* Sealant Fk09-016** - Local source

PR1436GB1-2 - AR* Sealant Fk09-017** - Local source

S15-60CRME52700 - AR* Aerodur Primer Fk07-008** - Local source

NOTES:* Use as much as necessary

** Refer to the CML for material numbers

*

1 Applicable to Part 1

*

2 Applicable to Part 4

*

3

1,6 mm (0.063 inch) 2024T3 Alclad aluminum sheet

*

4

2,0 mm (0.080 inch) 2024T3 Alclad aluminum sheet.

(2) These mod kit parts are necessary to do this Service Bulletin on 1 aircraft.

(a) Not applicable.
Service Bulletin

Fokker 70/100

SBF100-53-115 Jun 16/11

Page 8

Copyright All rights reserved by Fokker Services B.V. (The Netherlands). This document has been supplied by Fokker Services B.V. to its customers on a confidential basis subject to the provisions of an agreement. 

Reproduction or disclosure to third parties of this document or any part thereof, or the use of any information contained therein for purposes other than explicitly allowed by the aforesaid agreement, is not permitted 

except with the prior written permission of Fokker Services B.V.

C. Tooling – Price and Availability

(1) The following special tools are required to accomplish Part 2 and 3 of this Service 

Bulletin:

Part Number Specification Reference Supplier

ELOTEST-B1SB Phase analysis EC tester S0137* Rohmann

SPT4039 Sliding probe, reflection 

type, 1-100 kHz

- Servicing Europe 

NDT

CR-RE-TF180 Interconnecting cable - Servicing Europe 

NDT

SB10053115PLATE Calibration plate - Local source**

NOTES:* Reference number when ordering at Fokker services BV.

** Calibration plate pn SB10053115PLATE has to be manufactured in 

accordance with Part 1 of this Service Bulletin.

D. Drawings Required

(1) Not applicable.
Service Bulletin

Fokker 70/100

Jun 16/11 SBF100-53-115

Page 9

Copyright All rights reserved by Fokker Services B.V. (The Netherlands). This document has been supplied by Fokker Services B.V. to its customers on a confidential basis subject to the provisions of an agreement. 

Reproduction or disclosure to third parties of this document or any part thereof, or the use of any information contained therein for purposes other than explicitly allowed by the aforesaid agreement, is not permitted 

except with the prior written permission of Fokker Services B.V.

3. Accomplishment Instructions

General:

- For CML material number references, refer to “Myfokkerfleet.com/Documentation/CML” or 

AMM task 20-30-00-910-xxx-A (Consumable Material List).

- For Standards and Process Manual (SPM) references, refer to 

“Myfokkerfleet.com/Documentation/SPM”.

- For the application of Alodine 1201 (Fk13-003D), refer to the AMM, chapter 51-22-00.

- For the application of primer and paint, refer to the AMM, chapter 51-21-00.

- For the application of sealant PR1436GA1-2 (Fk09-016) and PR1436G-B1-2 (Fk09-017) 

refer to the AMM, chapter 51-23-00.

- For the removal/installation of solid rivets, refer to the SRM, chapter 51-40-02.

- For the installation of blind rivets, refer to the SRM chapters 51-40-03, 51-40-04 

and 51-40-05.

- For drilling and dimpling procedures, refer to the SRM, chapter 51-21-02.

- For drilling and countersinking procedures, refer to the SRM, chapter 51-22-01.

WARNING: BE CAREFUL WHEN YOU USE THE CONSUMABLE MATERIALS. OBEY 

THE INSTRUCTIONS AND MANUFACTURER'S HEALTH AND SAFETY 

INSTRUCTIONS.

Part 1: The Manufacturing of the Calibration Plate for the Inspection

Refer to figure 1.

A. Manufacturing of the calibration plate.

(1) Manufacture 2 plates A in accordance with figure 1 “Plate A”. Use:

- AR Sheet, aluminum pn F0N1-4311-2AD- *

NOTE: * 2,0 mm (0.080 inch) thick 2024T3 Alclad aluminium sheet.

(2) Manufacture 1 x plate B in accordance with figure 1 “Plate B”. Use:

- AR Sheet, aluminum pn F0N1-4311-1AP- *

NOTE: * 1,6 mm (0.063 inch) thick 2024T3 Alclad aluminium sheet.

(a) Make a small hole with a Ø 1,0 mm drill in plate B on the indicated position.

(b) Make a 10 mm long saw cut of 0,2 (± 0,1) mm wide with a jigsaw.

B. Assembly of the special tool.

(1) Assemble the special tool in accordance with figure 1 and use the plates 

manufactured in step A.(1) and A.(2). Use:

- AR Sealant, interfaying PR1436GA1-2* Fk09-016

NOTE: * Or equivalent
Service Bulletin

Fokker 70/100

SBF100-53-115 Jun 16/11

Page 10

Copyright All rights reserved by Fokker Services B.V. (The Netherlands). This document has been supplied by Fokker Services B.V. to its customers on a confidential basis subject to the provisions of an agreement. 

Reproduction or disclosure to third parties of this document or any part thereof, or the use of any information contained therein for purposes other than explicitly allowed by the aforesaid agreement, is not permitted 

except with the prior written permission of Fokker Services B.V.

C. Identification.

(1) Identify the special tool with pn SB10053115PLATE. Engrave the part number or use 

a permanent marker.
Service Bulletin

Fokker 70/100

Jun 16/11 SBF100-53-115

Page 11

Copyright All rights reserved by Fokker Services B.V. (The Netherlands). This document has been supplied by Fokker Services B.V. to its customers on a confidential basis subject to the provisions of an agreement. 

Reproduction or disclosure to third parties of this document or any part thereof, or the use of any information contained therein for purposes other than explicitly allowed by the aforesaid agreement, is not permitted 

except with the prior written permission of Fokker Services B.V.

Part 2: The Repetitive External Inspection of the Butt Joint at Stringer 12 between Stations

3850 and 5305 (applicable to F28 Mk 0100 Aircraft Serial Numbers 11268 thru 

11283, 11286, 11289, 11291, 11293, 11295, 11300, 11303, 11306, 11308, 11310, 

11312 thru 11314, 11316, 11318, 11321, 11323 thru 11335, 11337, 11338, 11340, 

11345, 11346, 11349, 11352 thru 11361, 11365 thru 11370, 11372, 11373, 11376 

thru 11380, 11387, 11388, 11391, 11392, 11395 thru 11399, 11403 thru 11408, 

11411 thru 11417, 11419, 11425 thru 11428, 11432, 11435, 11436, 11438, 11439, 

11444 thru 11450, 11456 thru 11460, 11464 thru 11469, 11475 thru 11479, 11481 

thru 11487, 11490 thru 11495, 11498, 11499, 11501, 11502, 11504, 11506, 11513 

thru 11515, 11519, 11520, 11522 and 11523).

NOTE 1: This part is not applicable to aircraft serial number 11418, because this aircraft has 

already been permanently repaired/modified (similar to the terminating 

repair/modification according SBF100-53-116).

NOTE 2: This procedure describes the external Low Frequency Eddy Current (LFEC) sliding 

probe inspection of the longitudinal butt joint at stringer 12 between frames 3850 

and 5305 below the forward opening passenger door.

A. Preparation of the of the inspection area.

Refer to figure 5.

(1) Clean the area to be inspected from any dirt with a lint-free cloth moistened with 

cleaning agent.

(2) Remove chipped and/or excessive paint. Refer to NDTM, Part 1, chapter 51-00-06.

B. The following special tools are required for the LFEC sliding probe inspection:

Part Number Specification Reference Supplier

ELOTEST-B1SB Phase analysis EC tester S0137* Rohmann

SPT4039 Sliding probe, reflection 

type, 1-100 kHz

- Servicing Europe NDT

CR-RE-TF180 Interconnecting cable - Servicing Europe NDT

SB10053115PLATE Calibration plate - Local source**

NOTES:* Reference number when ordering at Fokker services BV.

** Calibration plate pn SB10053115PLATE has to be manufactured in 

accordance with Part 1 of this Service Bulletin.
Service Bulletin

Fokker 70/100

SBF100-53-115 Jun 16/11

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Copyright All rights reserved by Fokker Services B.V. (The Netherlands). This document has been supplied by Fokker Services B.V. to its customers on a confidential basis subject to the provisions of an agreement. 

Reproduction or disclosure to third parties of this document or any part thereof, or the use of any information contained therein for purposes other than explicitly allowed by the aforesaid agreement, is not permitted 

except with the prior written permission of Fokker Services B.V.

C. Calibration of the measuring equipment.

Refer to figures 2 and 4.

INSTRUMENT SETTINGS

(a) Y/X or Y/time base Y/X

(b) Frequency (kHz) 3.0

(c) Axis spread Y/X (dB) 0/0

(d) Bandwidth MF

(e) Preamplifier (dB) 6

(f) Gain (dB) As required

(g) Phase (degrees) As required

(h) Filter (Hz) LP: 50

(i) Gate ON

(j) Alarm OFF

Initial instrument settings

Table 1

(1) Adjust the instrument according to table 1. Set the balance point at 25% Full Screen 

Height (FSH) and set the gate to 50% FSH as indicated in figure 4A.

(2) Position a non-conductive ruler in such a way that a straight scan can be made with 

the center mark of the probe along one skin edge of the butt joint. Refer figure 2.

NOTE: Centering halfway the splice may cause a non-relevant lift-off signal.

(3) Balance the instrument and adjust Phase to get a horizontal lift-off signature as 

shown in figure 4B.

(4) Scan from position I to position II until the maximum crack signal is obtained. Adjust 

Gain until the crack signal is 75% FSH. Refer figure 4B.

NOTE: Scan from position I to position II to familiarize with the signature from the 

saw-cut. A real crack may increase gradually and exceed 75% FSH.

D. Inspection of the butt joint.

Refer to figures 3, 4 and 5.

(1) Switch the alarm to ON. Inspect the area between the frames using a non-conductive 

ruler. For the inspection area refer to figure 5.

(2) Position the probe at a skin corner along one skin edge of the butt joint and balance 

the instrument. Refer figure 3.

(3) Perform a scan along each skin edge (refer figure 3) and monitor the signal. 
Service Bulletin

Fokker 70/100

Jun 16/11 SBF100-53-115

Page 13

Copyright All rights reserved by Fokker Services B.V. (The Netherlands). This document has been supplied by Fokker Services B.V. to its customers on a confidential basis subject to the provisions of an agreement. 

Reproduction or disclosure to third parties of this document or any part thereof, or the use of any information contained therein for purposes other than explicitly allowed by the aforesaid agreement, is not permitted 

except with the prior written permission of Fokker Services B.V.

NOTE: A misalignment of the ruler will decrease the detectability of cracks and 

cause deviating signatures.

(4) Mark every position where the signal passes the 50% FSH gate and looks like the slot 

signals given in figure 4B.

(5) If no indications above 50% FSH are measured continue with step F.

E. Verification of inspection results.

(1) Check the sensitivity setting on the calibration plate. Balance the probe on the aircraft

at an opposite skin corner or at a frame position without rivets in the inspection area 

and rescan the marked area(s).

NOTE: Adjacent to a through crack an indication may increase gradually and exceed 

75% FSH, unlike the saw-cut in the calibration plate.

(2) If a crack indication of 50% FSH or more is found, write down the location, orientation 

and the length of the crack.

F. After inspection procedure.

(1) If an indication of 50% FSH or more is found repair the applicable frame bay(s) in 

accordance with Part 4 of this Service Bulletin. If a crack indication of less than 50% 

FSH has been found continue with step F.

Refer to figure 10.

(2) Fill out the enclosed Reporting Form of figure 10. Send the filled out reporting form 

back to Fokker Services BV. For the address refer to SBF100-00-001 (Service 

Bulletin Introduction).

NOTE: This feed-back is essential for further determination of subsequent actions.

G. Job close up

(1) If necessary restore the aircraft paint scheme. Refer to the Aircraft Maintenance 

Manual (AMM), chapter 51-21-00.

(2) Remove all tools and materials from the work area and make sure the area is clean.
Service Bulletin

Fokker 70/100

SBF100-53-115 Jun 16/11

Page 14

Copyright All rights reserved by Fokker Services B.V. (The Netherlands). This document has been supplied by Fokker Services B.V. to its customers on a confidential basis subject to the provisions of an agreement. 

Reproduction or disclosure to third parties of this document or any part thereof, or the use of any information contained therein for purposes other than explicitly allowed by the aforesaid agreement, is not permitted 

except with the prior written permission of Fokker Services B.V.

Part 3: The Repetitive External Inspection of the Butt Joint at Stringer 61 between Stations

3850 and 5305 (Applicable to all aircraft listed in the paragraph 1.A. Effectivity). 

NOTE: This procedure describes the external Low Frequency Eddy Current (LFEC) sliding 

probe inspection of the longitudinal butt joint at stringer 61 between frames 3850 and 

5305 below the forward service/emergency door.

A. Preparation of the of the inspection area.

Refer to figure 6.

(1) Clean the area to be inspected from any dirt with a lint-free cloth moistened with 

cleaning agent.

(2) Remove chipped and/or excessive paint. Refer to NDTM, Part 1, chapter 51-00-06.

B. The following special tools are required for the LFEC sliding probe inspection:

Part Number Specification Reference Supplier

ELOTEST-B1SB Phase analysis EC tester S0137* Rohmann

SPT4039 Sliding probe, reflection 

type, 1-100 kHz

- Servicing Europe NDT

CR-RE-TF180 Interconnecting cable - Servicing Europe NDT

SB10053115PLATE Calibration plate - Local source**

NOTES: * Reference number when ordering at Fokker services BV.

** Calibration plate pn SB10053115PLATE has to be manufactured in 

accordance with Part 1 of this Service Bulletin.

C. Calibration of the measuring equipment.

Refer to figures 2 and 4.

INSTRUMENT SETTINGS

(a) Y/X or Y/time base Y/X

(b) Frequency (kHz) 3.0

(c) Axis spread Y/X (dB) 0/0

(d) Bandwidth MF

(e) Preamplifier (dB) 6

(f) Gain (dB) As required

(g) Phase (degrees) As required

(h) Filter (Hz) LP: 50

(i) Gate ON

(j) Alarm OFF

Initial instrument settings

Table 1
Service Bulletin

Fokker 70/100

Jun 16/11 SBF100-53-115

Page 15

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Reproduction or disclosure to third parties of this document or any part thereof, or the use of any information contained therein for purposes other than explicitly allowed by the aforesaid agreement, is not permitted 

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(1) Adjust the instrument according to table 1. Set the balance point at 25% Full Screen 

Height (FSH) and set the gate to 50% FSH as indicated in figure 4A.

(2) Position a non-conductive ruler in such a way that a straight scan can be made with 

the center mark of the probe along one skin edge of the butt joint. Refer figure 2.

NOTE: Centering halfway the splice may cause a non-relevant lift-off signal.

(3) Balance the instrument and adjust Phase to get a horizontal lift-off signature as 

shown in figure 4B.

(4) Scan from position I to position II until the maximum crack signal is obtained. Adjust 

Gain until the crack signal is 75% FSH. Refer figure 4B.

NOTE: Scan from position I to position II to familiarize with the signature from the 

saw-cut. A real crack may increase gradually and exceed 75% FSH.

D. Inspection of the butt joint.

Refer to figures 3, 4 and 6.

(1) Switch the alarm to ON. Inspect the area between the frames using a non-conductive 

ruler. For the inspection area refer to figure 6.

(2) Position the probe at a skin corner along one skin edge of the butt joint and balance 

the instrument. Refer figure 3. 

(3) Perform a scan along each skin edge (refer figure 3) and monitor the signal. 

NOTE: A misalignment of the ruler will decrease the detectability of cracks and 

cause deviating signatures.

(4) Mark every position where the signal passes the 50% FSH gate and looks like the slot 

signals given in figure 4B.

(5) If no indications above 50% FSH are measured continue with step F.

E. Verification of inspection results.

(1) Check the sensitivity setting on the calibration plate. Balance the probe on the aircraft 

at an opposite skin corner or at a frame position without rivets in the inspection area 

and rescan the marked area(s). 

NOTE: Adjacent to a through crack an indication may increase gradually and exceed 

75% FSH, unlike the saw-cut in the calibration plate.

(2) If a crack indication of 50% FSH or more is found, write down the location, orientation 

and the length of the crack.
Service Bulletin

Fokker 70/100

SBF100-53-115 Jun 16/11

Page 16

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Reproduction or disclosure to third parties of this document or any part thereof, or the use of any information contained therein for purposes other than explicitly allowed by the aforesaid agreement, is not permitted 

except with the prior written permission of Fokker Services B.V.

F. After inspection procedure.

(1) If an indication of 50% FSH or more is found repair the applicable frame bay(s) in 

accordance with Part 4 of this Service Bulletin. If a crack indication of less than 50% 

FSH has been found continue with step F.

Refer to figure 10.

(2) Fill out the enclosed Reporting Form of figure 10. Send the filled out reporting form 

back to Fokker Services BV. For the address refer to SBF100-00-001 (Service 

Bulletin Introduction).

NOTE: This feed-back is essential for further determination of subsequent actions.

G. Job close up

(1) If necessary restore the aircraft paint scheme. Refer to the Aircraft Maintenance 

Manual (AMM), chapter 51-21-00.

(2) Remove all tools and materials from the work area and make sure the area is clean.
Service Bulletin

Fokker 70/100

Jun 16/11 SBF100-53-115

Page 17

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Reproduction or disclosure to third parties of this document or any part thereof, or the use of any information contained therein for purposes other than explicitly allowed by the aforesaid agreement, is not permitted 

except with the prior written permission of Fokker Services B.V.

Part 4: The Temporary Repair of the Butt Joint(s)

Refer to figures 7, 8 and 9.

A. Repair the frame bays where the cracks are found or all frame bays as a precautionary 

measure as follows:

(1) Remove the fasteners in the applicable frame bay. Leave the fasteners at the frames 

installed.

NOTE: When cracks are found on each side of a frame, repair the frame bay forward 

and aft of the frame. Do not install the repair patch over the frame. 

B. Manufacture a repair patches.

(1) Manufacture repair patches that extend from frame to frame in accordance with 

figures 7 and 8. Use:

- AR Sheet, aluminum pn F0N1-4311-1AP- *

NOTE: * 1,6 mm (0.063 inch) thick 2024T3 Alclad aluminum sheet.

(2) Temporary install the repair patches and copy drill the existing attachment in holes 

into the repair patches.

(3) Deburr all holes and protect all bare aluminum with Alodine and primer. Use:

- AR Coating pn Alodine 1201 Fk13-003D

- AR Primer pn S15-60CRME52700 Fk07-008

C. Installation of the repair plate(s).

(1) Install all repair parts with blind rivets, repair washers (refer to SRM 51-43-04) and

interfaying sealant and aerodynamically seal the edges of the repair patches. Use: 

- AR Sealant pn PR1436GA1-2 Fk09-016

- AR Sealant pn PR1436GB1-2 Fk09-017

- AR CSK blind rivets pn F0N2-6395B5xx

- AR CSK blind rivets pn F0N2-6397B6xx *

- AR CSK repair washers pn F0N18-9151S05

- AR CSK repair washers pn F0N18-9151S06 *

NOTE:* In the stringer connection angles at stations 3850 and 5305 in -6 rivets are 

installed. These rivets have to be replaced by reduced countersunk head 

blind rivets with pn F0N2-6397B6xx (CR3224-6-xx).

(2) Restore the original paint scheme according to AMM 51-21-00.

D. Job close up.

(1) Remove all tools, materials and equipment from the working area. Make sure that the 

working area is clean.

NOTE: If the temporary repair has been performed record in the aircraft documentation 

the ECR (ECR015780) as well as when and which frame bay(s) have been 

repaired, for easy determination of applicability of future actions.
Service Bulletin

Fokker 70/100

SBF100-53-115 Jun 16/11

Page 18

Copyright All rights reserved by Fokker Services B.V. (The Netherlands). This document has been supplied by Fokker Services B.V. to its customers on a confidential basis subject to the provisions of an agreement. 

Reproduction or disclosure to third parties of this document or any part thereof, or the use of any information contained therein for purposes other than explicitly allowed by the aforesaid agreement, is not permitted 

except with the prior written permission of Fokker Services B.V.

Pos. Description t Dimensions Material Remarks

A Sheet 2,0 200 x 49 2024T3 Alclad 2x

B Sheet 1,6 200 x 80 2024T3 Alclad -

C Sealant 0,2 - PR1436GA1-2 or equivalent

D Crack - 10,0 x 0,2 ±0,1 Saw cut Pre drill Ø 1,0 mm

E Tool no. - - Engrave/mark SB10053115PLATE

All dimensions in mm

The Manufacturing of the Calibration Plate (Part 1).

Figure 1

A

B

A

C

4

4

10

200

49

2,0

100 80 

E

Ø 1,0 

SB10053115PLATE

D
Service Bulletin

Fokker 70/100

Jun 16/11 SBF100-53-115

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Reproduction or disclosure to third parties of this document or any part thereof, or the use of any information contained therein for purposes other than explicitly allowed by the aforesaid agreement, is not permitted 

except with the prior written permission of Fokker Services B.V.

Slot position on Calibration Plate.

Figure 2

Typical Scan Pattern on the Butt Joint (Parts 2 and 3).

Figure 3

I II I

SB10053115PLATE

PROBE

Scan pattern 

Typical crack

in butt strap

Probe starting point

Frame

Non-conductive

ruler
Service Bulletin

Fokker 70/100

SBF100-53-115 Jun 16/11

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Copyright All rights reserved by Fokker Services B.V. (The Netherlands). This document has been supplied by Fokker Services B.V. to its customers on a confidential basis subject to the provisions of an agreement. 

Reproduction or disclosure to third parties of this document or any part thereof, or the use of any information contained therein for purposes other than explicitly allowed by the aforesaid agreement, is not permitted 

except with the prior written permission of Fokker Services B.V.

Screen Indications (Parts 1, 2 and 3).

Figure 4

0%

25%

50%

75%

100%

0

2

4

6

8

10 5 3 0

B

0%

25%

50%

75%

100%

0

2

4

6

8

10 5 3 0

A

Crack indication

Lift-off indication
Service Bulletin

Fokker 70/100

Jun 16/11 SBF100-53-115

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Copyright All rights reserved by Fokker Services B.V. (The Netherlands). This document has been supplied by Fokker Services B.V. to its customers on a confidential basis subject to the provisions of an agreement. 

Reproduction or disclosure to third parties of this document or any part thereof, or the use of any information contained therein for purposes other than explicitly allowed by the aforesaid agreement, is not permitted 

except with the prior written permission of Fokker Services B.V.

The Inspection Area of the Butt Joint at Stringer 12 between Stations 3850 and 5305

below the Forward Opening Passenger Door (Part 2).

Figure 5

Inspection area

Forward

opening

passenger

door

Stgr 12
Service Bulletin

Fokker 70/100

SBF100-53-115 Jun 16/11

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Copyright All rights reserved by Fokker Services B.V. (The Netherlands). This document has been supplied by Fokker Services B.V. to its customers on a confidential basis subject to the provisions of an agreement. 

Reproduction or disclosure to third parties of this document or any part thereof, or the use of any information contained therein for purposes other than explicitly allowed by the aforesaid agreement, is not permitted 

except with the prior written permission of Fokker Services B.V.

The Inspection Area of the Butt Joint at Stringer 61 between Stations 3870 and 5305

below the Forward Service/Emergency Door (Part 3).

Figure 6

Inspection area

Forward

S/E door

Stgr 61
Service Bulletin

Fokker 70/100

Jun 16/11 SBF100-53-115

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Reproduction or disclosure to third parties of this document or any part thereof, or the use of any information contained therein for purposes other than explicitly allowed by the aforesaid agreement, is not permitted 

except with the prior written permission of Fokker Services B.V.

Round of the Edges of the Repair Patch and Aerodynamically Seal the Edges (Part 4).

Figure 7

Aerodynamically seal

all the edges

Aerodynamically seal

all the edges

A A

Section A-A

(before application of sealant)

Section A-A

(after application of sealant)

Round-off

edges

R (R = t)

t

External repair patch

External repair patch
Service Bulletin

Fokker 70/100

SBF100-53-115 Jun 16/11

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Copyright All rights reserved by Fokker Services B.V. (The Netherlands). This document has been supplied by Fokker Services B.V. to its customers on a confidential basis subject to the provisions of an agreement. Reproduction or disclosure to third parties of this document or any part thereof, or the use of any information contained therein for purposes other than explicitly allowed by the aforesaid agreement, is not permitted except with the prior 

written permission of Fokker Services B.V.

Temporary Repair of the Frame Bays (Part 4).

Figure 8

Repair patches made from 2024T3 Alclad (t = 1,6 mm)

NOTES: LH side (stringer 12) drawn and RH side (stringer 61) opposite

RH side stringer numbers are between parentheses

(STGR 61) 

(STGR 61) 

(STGR 60) 

Detail Z Only applicable to aircraft with a hinged ground 

connection panel 127AB (refer to figure 9)

DOF
Service Bulletin

Fokker 70/100

Jun 16/11 SBF100-53-115

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Copyright All rights reserved by Fokker Services B.V. (The Netherlands). This document has been supplied by Fokker Services B.V. to its customers on a confidential basis subject to the provisions of an agreement. Reproduction or disclosure to third parties of this document or any part thereof, or the use of any information contained therein for purposes other than explicitly allowed by the aforesaid agreement, is not permitted except with the prior 

written permission of Fokker Services B.V.

Deviation of the Temporary Repair Patches at the External Reinforcement Doubler

(only applicable to Aircraft with a Hinged Ground Connection Panel 127AB (Part 4)).

Figure 9

Sta 4850

DOF

Stgr 61

Stgr 62

External

reinforcement

doubler
Service Bulletin

Fokker 70/100

SBF100-53-115 Jun 16/11

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Copyright All rights reserved by Fokker Services B.V. (The Netherlands). This document has been supplied by Fokker Services B.V. to its customers on a confidential basis subject to the provisions of an agreement. Reproduction or disclosure to third parties of this document or any part thereof, or the use of any information contained therein for purposes other than explicitly allowed by the aforesaid agreement, is not permitted except with the prior 

written permission of Fokker Services B.V.

Operator:

Aircraft Serial Number:

Flight cycles:

Flight hours:

Indicate on the figure the crack location direction and fill in the table the length

Crack number: Stgr no: (12 or 61) Crack length: (mm or inch) Position*: (mm or inch) 

* Distance FWD crack tip to nearest FWD frame.

Reporting Form.

Figure 10

(STGR 61) 

(STGR 61) 

(STGR 62) 

DOF
Service Bulletin Reporting Quality Form

Fokker 70/100

Jun 16/11 SBF100-53-115

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Service Bulletin Reporting Quality Form

Use this Service Bulletin Reporting Quality Form to tell us your perception of the quality of the Service 

Bulletin. The reported data that you provide to us will be used to analyze areas of difficulties and to take 

corrective actions to further improve the quality of our Service Bulletins.

We thank you for the time you have taken in completing this form.

* Rate the scale of 1 to 4, with 1 the lowest score and 4 the highest score.

Chapters * 1 2 3 4

a) Quality rating of this SB (overall) □ □ □ □

b) Quality rating of the Planning Information □ □ □ □

c) Quality rating of the Material Information □ □ □ □

d) Quality rating of the Accomplishment Instructions □ □ □ □

e) Quality rating of the Test Instructions (if applicable) □ □ □ □

f) Quality rating of the Illustrations or Drawings (if applicable) □ □ □ □

g) Timely delivery of the SB □ □ □ □

If you have had difficulties with one of the chapters of this Service Bulletin and/or one of your 

rating(s) is (are) lower than 3, please give a short description of the issue.

Comments:

Operator: Date:

Name / Title: 

Please return this form to: Fokker Services B.V.

Technical Services, Quality Department

P.O. box 231

2150 AE Nieuw-Vennep

The Netherlands