## Service Bulletin Fokker 50/60

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 there in for purposes other than explicitly allowed by the aforesaid agreement, is not permitted except with the prior written permission of Fokker Services B.V.

May 27/10 SBF50-28-027 Revision 1, Aug 20/10 Page 1 1. Planning Information A. Effectivity (1) F27 Mark 050, 0502 and 0604 aircraft serial number(s): 20103 thru 20335. B. Concurrent Requirements (1) Not applicable.

C. Reason (1) To improve the protection against chafing, a rubber sleeve around the cables of the fuel quantity probes was introduced with (optional) Service Bulletin SBF50-28-004 in 1989. (2) The subsequent design review of the F27 Mk 050, 0502 and 0604 fuel system in accordance with the guidelines related to FAA SFAR 88 and JAA INT/POL/25/12 revealed that an unsafe condition can develop in the wing tanks if chafing occurs between cables of the fuel quantity probes and the probes. With additional factors, this may result in an ignition source in the wing tank vapour space. (3) This Service Bulletin introduces a check and modification to assure that the additional protection against chafing (rubber sleeve and cable tie) around the electrical cables near the fuel quantity probes in the left and right wing tanks is installed.

Page 1 2 3 4 5 6 7 8 9

Revision 1 1 1 1 - - 1 1 - This Service Bulletin supersedes Service Bulletin SBF50-28-004

FUEL “This Service Bulletin is associated with the Fuel Tank Safety Program” Quantity Indication - The Check on the Presence and, if applicable, the Installation of Rubber Sleeves and Cable Ties around the Cables of the Fuel Quantity Probes

## Service Bulletin Fokker 50/60

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 there in for purposes other than explicitly allowed by the aforesaid agreement, is not permitted except with the prior written permission of Fokker Services B.V.

SBF50-28-027 May 27/10 Page 2 Revision 1, Aug 20/10 Reason for revision (1) This revision is made to: - Renumber the paragraphs in page 4. The paragraph: “Special Instructions for Continued Airworthiness (ICA)” is para 1.L.(1).(c) and consequently the paragraph: Operational Documentation” 1.L.(1).(c) becomes 1.L.(1).(d), - Renumber the paragraphs in page 7 and 8, Part 1 and Part 2

. - incorporate some editorial changes. - Change the Service Bulletin layout (header). D. Description (1) This Service bulletin consist out of two parts:

Part 1: Check the Presence of Rubber Sleeves and Cable Ties. This part tells you how to check the presence of the rubber sleeve and cable tie on the cables of the fuel quantity probes.

Part 2: Installation of Rubber Sleeves and Cable Ties. This part tells you how to install the rubber sleeve and cable tie (if required) on the cables of the fuel quantity probes. E. Compliance (1) Recommended.

Part 1 : Fokker Services recommends the accomplishment of part 1 of this Service Bulletin not later than 1 May 2023.

Part 2 : If applicable, Fokker Services recommends the accomplishment of Part 2 of this Service Bulletin before further flight after accomplishment of Part 1

. NOTE : Because of the required tank opening it is efficient to do this Service Bulletin concurrently with a scheduled tank inspection before the above compliance date.

NOTE : 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 a Proposed Airworthiness Directive for comments. F. Approval (1) The technical content of this document is approved by EASA or under the authority of DOA nr. EASA.21J.059.

## Service Bulletin Fokker 50/60

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 there in for purposes other than explicitly allowed by the aforesaid agreement, is not permitted except with the prior written permission of Fokker Services B.V.

May 27/10 SBF50-28-027 Revision 1, Aug 20/10 Page 3 G. Manpower (1) Less than 0.25 man-hours are necessary to do Part 1 of this Service Bulletin on 1 aircraft if it is combined with a scheduled opening of the tank area panels. (2) Approximately 20 man-hours are necessary to do Part 2 of this Service Bulletin on one aircraft. This table of manpower will help you to schedule and do Part 2 of this Service Bulletin:

Instructions Men Man-hours Elapsed time (hours) Inspection - - - Removal 2 7,0 3,5 Modification Installation 2 11,0 5,5 Testing 2 2,0 1,0 Total 20,0 10,0

NOTES : This estimate does not include the time necessary: - For the paint to dry and the sealant to cure. - To ventilate the fuel tank necessary for doing safe maintenance in the fuel tank Ref AMM Task 28-11-00-610-813-A. (3) The estimated hours are for direct labor done by experienced personnel. They are calculated based on the conditions given in SBF50-00-001 (Service Bulletin Introduction, section 2.C., "Manpower"). H. Weight and Balance (1) Weight change: None Index change: None.

I. Electrical Load Data (1) Not affected. J. Software Accomplishment Instructions (1) Not applicable.

K. References (1) Fokker 50/60 Aircraft Maintenance Manual (AMM) Fokker internal reference(s): - ECR 76775.

## Service Bulletin Fokker 50/60

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 there in for purposes other than explicitly allowed by the aforesaid agreement, is not permitted except with the prior written permission of Fokker Services B.V.

SBF50-28-027 May 27/10 Page 4 Revision 1, Aug 20/10 L. Publications Affected (1) This SB affects the publications listed below: (a) Maintenance Documentation - Fokker 70/100 Aircraft Maintenance Manual (AMM) - chapter 28-41 NOTE : See attached Manual Change Notification MCNM F50-067.

(b) Maintenance Programs Fokker 50/60 Maintenance Review Board (MRB). (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 Systems (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, the CDCCL item as specified below shall be followed. CDCCL: In case of replacement or removal / installation of the LH and RH FQIS probes or probe wiring, it shall be assured that the rubber sleeve around the wires and the cable tie around the probe and sleeve remain in place in accordance with the post SBF50-28-027 configuration.

NOTE : The verification shall be performed in accordance with the instructions in the AMM task 28-41-01-400-814-A, changed in accordance with the change instructions in the attached MCNM F50-067. (d) Operational Documentation

Not affected. (2) For incorporation of this Service Bulletin in your documentation refer to SBF50-00-001 (Service Bulletin Introduction, section 4 "Incorporation of Service Bulletins in Documentation of Fokker Services").

## Service Bulletin Fokker 50/60

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 there in for purposes other than explicitly allowed by the aforesaid agreement, is not permitted except with the prior written permission of Fokker Services B.V.

May 27/10 SBF50-28-027 Page 5 M. Interchangeability or Intermixability of Parts (1) Not applicable.

## Service Bulletin Fokker 50/60

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 there in for purposes other than explicitly allowed by the aforesaid agreement, is not permitted except with the prior written permission of Fokker Services B.V.

SBF50-28-027 May 27/10 Page 6 2. Material Information A. Material – Price and Availability (1) You can order the necessary parts against list price. B. Material Required (1) These parts which are necessary to complete this Service Bulletin on 1 aircraft , are not part of the mod kit. (a) Not applicable (2) These parts are necessary to do Part 2 of this Service Bulletin on 1 aircraft.

New Part Number Qty Keyword Info Old Part Number Instructions/ Disposition

F0N1-3506-HT75 5m Rubber sleeve - - - F0N9-1509AN9 10 Cable tie - F0N9-1509AN9 Discard

NOTE : The part numbers of the fuel quantity probes are not affected by this change. C. Tooling – Price and Availability (1) Not applicable. D. Drawings Required (1) Not applicable.

## Service Bulletin Fokker 50/60

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 there in for purposes other than explicitly allowed by the aforesaid agreement, is not permitted except with the prior written permission of Fokker Services B.V.

May 27/10 SBF50-28-027 Revision 1, Aug 20/10 Page 7 3. Accomplishment Instructions

General: - For finish codes references, refer to “Myfokkerfleet.com/Documentation/FC”.

- For CML material number references, refer to “Myfokkerfleet.com/Documentation/CML”. WARNING : BE CAREFUL WHEN YOU USE THE CONSUMABLE MATERIALS. OBEY THE INSTRUCTIONS AND MANUFACTURER'S HEALTH AND SAFETY INSTRUCTIONS. WARNING : OBEY THE SAFETY PRECAUTIONS AND WARNINGS GIVEN IN THE FOKKER 50 AIRCRAFT MAINTENANCE MANUAL, CHAPTERS 28-00-00 AND 28-11-00. JET FUEL IS EXPLOSIVE AND POISONOUS. - Put up warning signs to tell personnel: "DO NOT USE FLAMES OR EQUIPMENT THAT CAUSES SPARKS". - These Accomplishment Instructions are applicable to both the left and the right installations. - Information for the right installation is given inside parentheses. - The Accomplishment Instructions given are applicable to one fuel quantity probe, but are the same for all the fuel quantity probes. A. Open, tag and safety these circuit breakers:

- IND FUEL CONT LH CB1 CB0421A - FUEL CPT LH PWR CB1 CB0420A - IND FUEL CONT RH CB2 CB0422A - FUEL CPT RH PWR CB2 CB0423A - FUELING CB2 CB0972A.

B. De-fuel and drain the main fuel tanks. Refer to the Fokker 50 Aircraft Maintenance Manual, chapter 12-11. C. Remove access panels 521BB (621BB), 521CB (621CB), 521DB (621DB), 521EB (621EB) and 521FB (621FB).Refer to AMM chapter 57-24-00-000-814-A). D. Remove the flammable vapor from the main tanks. Refer to AMM, chapter 28-11.

Part 1 : Check the Presence of Rubber Sleeves and Cable Ties. Refer to figure 1

Probe Number Part Number 1 0208KTU01 (0208KTU01) 2 0208KTU02 (0208KTU02) 3 0208KTU03 (0208KTU03) 4 0208KTU04 (0208KTU04) 5 0208KTU05 (0208KTU05).

## Service Bulletin Fokker 50/60

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 there in for purposes other than explicitly allowed by the aforesaid agreement, is not permitted except with the prior written permission of Fokker Services B.V.

SBF50-28-027 May 27/10 Page 8 Revision 1, Aug 20/10 A. For each probe, check if a r ubber sleeve and a cable tie are installed. B. If for one or more probes, a sleeve and/or a cable tie is not installed, continue with Part 2 of this Service Bulletin. C. If a sleeve and a cable tie are installed on all probes, continue with Finishing of the aircraft and aircraft test: step A.

Part 2 : Installation of Rubber Sleeves and Cable Ties. Refer to figure 1. A. For each affected probe, make a modification as follows: (1) Remove and discard 1 cable tie p/n F0N9-1509AN9 that secures the 3 cables (4 cables to probe no #1) to the fuel quantity probe. (2) Disconnect the terminals from the probe. (3) Install 1 rubber sleeve p/n F0N1-3506-HT75 around the 3 cables (4 cables to probe no #1). (4) Connect the terminals to the probe and torque the screws in accordance with TH4.328 section 5.4. (5) Secure the rubber sleeve to the fuel quantity probe with 1 cable tie p/n F0N9- 1509AN9 44,5 mm (1.75 in) below the cable terminals. (6) Continue with Finishing of the aircraft and aircraft test: step A.

Finishing of the aircraft and aircraft test A. Make sure that the work area is clean, and that all tools, materials and equipment are removed. B. Do the tank closure inspection. Refer to AMM chapter 28-11-00. C. Install the panels that you removed for access in step 3 C. Refer to AMM chapter 57-24- 00. D. Close the circuit breakers that you opened in 3. General step A. E. Refuel the main fuel tanks. Refer to AMM, chapter 12-11. F. Do a leak check. Refer to AMM, chapter 28-00-00. G. Do an operational test of the fuel quantity indicating system. Refer to AMM, chapter 28-41- 00.

## Service Bulletin Fokker 50/60

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 there in for purposes other than explicitly allowed by the aforesaid agreement, is not permitted except with the prior written permission of Fokker Services B.V.

May 27/10 SBF50-28-027 Page 9 Modification to the Fuel-Quantity-Probe Installations Figure 1