## Service Bulletin Fokker 70/100

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.

Apr 27/09 SBF100-27-092 Page 1 FLIGHT CONTROLS

Horizontal Stabilizer - Introduction of Bolts with increased corrosion protection in the Stabilizer Control Unit Dog-Links

1. Planning Information

A. Effectivity

(1) F28 Mark 0100 aircraft serial numbers:

11244 thru 11527.

(2) Production version of this modification: Not applicable.

B. Concurrent Requirements

(1) Not applicable.

Page 1 2 3 4 5 6 7 8

Revision - - - - - - - -

## Service Bulletin Fokker 70/100

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.

SBF100-27-092 Apr 27/09 Page 2 C. Reason

(1) Recently on two Fokker 100 a/c, during accomplishment of task 062307-00-01, surveillance inspection of vertical stabilizer, it was found that bolt pn 23233-1 that connects the Horizontal Stabilizer Control Unit (HSCU) actuator with the doglinks, was broken (one on the nut side & one on the head side). In both occasions, the bolt shaft was still present in the connection and therefore the horizontal stabilizer function was not affected. The failed bolts were replaced and as a precaution the other bolts were also replaced. Subsequently 7 more a/c of the same Operator were inspected without further findings.

(2) The horizontal stabilizer is connected to the HSCU actuator via two doglinks. If one of the connections fails the complete stabilizer load can be taken by the remaining doglink. Failure of the connection may stay undetected until the next scheduled surveillance inspection. The interval of the task is 4000 FH. When the bolt fails at the nut-end then the remaining part of the bolt can not drop out of the connection due to the limited amount of space available between the bolt-head and the plate which is installed in between the two bolts. In this way the affected connection is still able to carry the system loads. If the head side of the bolt fails then in the end the bolt may drop out of the connection.

(3) In January 1996 Fokker issued Service Bulletin SBF100-27-069 (Goodrich SB 23100-27-19). This SB was issued to introduce an inspection of the same bolts for cracks. Additionally the same SB introduced a lower torque for these bolts. Reason for the mandatory SB with a compliance of 3 months for lowering of the torque and 9 months for the inspection, was the outcome of the examination of a failed bolt. The examination revealed that the bolt broke due to stress corrosion. The stress corrosion was attributed to a too high bolt torque. Since issuance of SBF100-27-069, four bolt failures are known to FS. In three of these events the bolt failed at the head side.

(4) Investigation of two of the recently failed bolts showed that the terminating action as given in SBF100-27-069 was apparently not fully effective. Therefore, SBF100-27-091 was issued in August 2007 to safeguard fleet airworthiness for the short term. As a result of the accomplishment of SBF100-27-091 over 50 bolts were replaced. To ensure the integrity on the long term Goodrich introduced a bolt with an improved corrosion protection i.e. pn 23233-3 with CSB 23100-27-29. After the introduction of the improved bolt, the tie-wrap that was introduced as a temporary measure with SBF100-27-091 is deleted.

NOTE : This SB is a cover for CSB 23100-27-29.

## Service Bulletin Fokker 70/100

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.

Apr 27/09 SBF100-27-092 Page 3 D. Description

(1) This Service Bulletin tells you how to:

- Remove the tie-wrap and the lower bolts of the HSCU.

- Install the improved bolts in the HSCU.

E. Compliance

(1) Recommended

Fokker Services recommends the accomplishment of this Service Bulletin within 30 months after the issue date of this Service Bulletin.

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.

G. Manpower

(1) Approximately 7 man-hours are necessary to do this Service Bulletin on one aircraft.

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

Instructions Men Man-hours Elapsed time (hours)
Removal Modification Inspection 2 3,0 1,5

Installation 2 3,0 1,5
Testing 2 1,0 0,5

Total 7,0 3,5

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

(2) 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").

H. Weight and Balance

## Service Bulletin Fokker 70/100

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.

SBF100-27-092 Apr 27/09 Page 4 (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 100 Aircraft Maintenance Manual (AMM) Fokker Consumable Material List (CML) Fokker 100 Service Bulletin (SB): - SBF100-27-037 - SBF100-27-069 - SBF100-27-091 Fokker internal reference(s): - ECR 15583 Goodrich CSB 23100-27-29.

L. Publications Affected

(1) This SB affects the publications listed below:

(a) Maintenance Documentation

-Fokker 100 Illustrated Parts Catalog (IPC) - chapter 27-42

NOTE: See attached Manual Change Notification MCNM F100-137.

(b) Maintenance Programs

Not affected.

(c) Special Instructions for Continued Airworthiness (ICA)

This Service Bulletin requires a revision to the Instructions for Continued Airworthiness (ICA) for:

YES NO - Electrical Wiring Interconnection System (EWIS) - X - Fuel Tank Safety (FTS) - X - Damage Tolerance of Fatigue Critical Structure - X

(d) Operational Documentation

## Service Bulletin Fokker 70/100

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.

Apr 27/09 SBF100-27-092 Page 5 Not affected.

(2) 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

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.

SBF100-27-092 Apr 27/09 Page 6 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 this Service Bulletin on 1 aircraft, are not part of the mod kit.

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

23233-3 2 Bolt 23233-1 New F0N2-2210-10 AR Nut F0N2-2210-10 Local source Mastinox 6856H * Jointing Compound Fk05-003 ** Local source

Mastinox 6856K * Jointing Compound Fk05-010A ** Local source

MS24665-155 AR Cotter Pin MS24665-155 Local source MS24665-374 AR Cotter Pin MS24665-374 Local source 2 Tie-wrap MS3367-2-9 Discard

NOTES : * Use as much as necessary ** Refer to the CML for material numbers.

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

(a) Not applicable.

C. Tooling – Price and Availability

(1) Not applicable.

D. Drawings Required

(1) Not applicable.

## Service Bulletin Fokker 70/100

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.

Apr 27/09 SBF100-27-092 Page 7 3. Accomplishment Instructions

General

- Refer to the CML for material numbers. - For removal and installation of the HSCU bolts refer to AMM 27-42-01-000-814 & AMM 27-42-01-400-814.

A. Modify the HSCU.

Ref. figure 1.

(1) Removal of bolts and tie-wraps. Remove and discard:

- 2 Tie-wrap MS3367-2-9 Discard - 2 Bolt 23233-1 Discard

(2) Install the improved bolts. Use:

- 2 Bolt 23233-3 New - AR Jointing Compound Mastinox 6856H or Mastinox 6856K Fk05-003 Fk05-010A - AR Cotter Pin MS24665-155 - AR Cotter Pin MS24665-374

B. Do a test of the top anti-collision light.

Action Result (1) On the overhead panel, on the EXT LIGHTS panel, push the BEACON pushswitch (a)

(b) The BEACON pushswitch OFF legend goes off. The top anti-collision light starts to flash. (2) On the overhead panel, on the EXT LIGHTS panel, push the BEACON pushswitch. (a)

(b) The BEACON pushswitch OFF legend comes on. The top anti-collision light goes off.

C. Remove all tools, material and equipment from the working area. Make sure the working area is clean.

D. Move the Horizontal Stabilizer through its complete range of travel and make sure that no interferences are present.

## Service Bulletin Fokker 70/100

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.

SBF100-27-092 Apr 27/09 Page 8 Figure 1 – HSCU Bolt Installation 

### *

* Modify the HSCU as follows:

Ref. AMM 27-42-01-000-814 & AMM 27-42-01-400-814.

- Cut and discard the tie-wraps. - Remove and discard bolts * pn 23233-1. - Install bolt* pn 23233-3.

## Manual Change Notification – Maintenance Documentation Fokker 70/100

APR 17/09 MCNM F100-137 Page 1 of 1 

### MCNM-F100-137

Subject : Flight Controls –Horizontal Stabilizer – Introduction of Bolts with increased corrosion protection in the Stabilizer Control Unit Dog-Link.
Reason : This MCN is issued to provide you with the changes on the content(s) of the affected manual(s), due to the introduction of SBF100-27-092.
Effectivity : Refer to SBF100-27-092.
Compliance : Once you have determined the applicability of this MCN for one or more of your aircraft, incorporate this information into the applicable manual(s).

Publications affected : The Illustrated Parts Catalogue (IPC).
Change Note : IPC

Update IPC Figure 27-42-01-01, as folllows:

- Change the partnumber of the Bolt (Fig. item 190) to 23233-3

- In the nomenclature of Fig. item 170 A thru 170 G (as applicable), add the text “SB27-29”.

NOTE : If you have a Document Revision Service (DRS) with Fokker Services, this MCN will be included into your IPC, at the earliest opportunity.