EASA AD No.: 2009-0220

EASA Form 110 Page 1/2 

## EASA AIRWORTHINESS DIRECTIVE

AD No.: 2009-0220

Date: 14 October 2009

Note: This Airworthiness Directive (AD) is i ssued by EASA, acting in accordance with Regulation (EC) No 216/2008 on behalf of the European Community, its Member States and of the European third countries that participate in th e activities of EASA under Article 66 of that Regulation.

This AD is issued in accordance with EC 1702/2003, Part 21A.3B. In accordance with EC 2042/2003 Annex I, Part M.A.301, the continuing airworthiness of an aircraft shall be ensured by accomplishing any applicable ADs. Consequently, no person may opera te an aircraft to which an AD applies, except in accordance with t he requirements of that AD, unless otherwise specified by the Ag ency [EC 2042/2003 Annex I, Part M.A.303] or agreed with the Authority of the State of Registry [EC 216/2008, Article 14(4) exemptio n].


### Type Approval Holder’s Name :

Fokker Services B.V. Type/Model designation(s) :

F28 Mark 0070 and Mark 0100 aeroplanes

TCDS Number : EASA.A.037

Foreign AD : Not applicable

Supersedure : None



### ATA 32 Landing Gear – Parking Brake Shut-off Valve (PBSOV) – Replacement

Manufacturer(s): Fokker Aircraft B.V.

Applicability: F28 Mark 0070 and Mark 0100 aeroplanes, all serial numbers.

Reason: When preparing for landing, the flight crew of a F28 Mark 0100 (Fokker 100) aeroplane observed a main landing gear (MLG) unsafe indication after landing gear down selection. The approach was aborted and the landing gear unsafe procedure was accomplished. As this di d not produce the desired effect, a low pass was performed and the control towe r confirmed that the right (RH) MLG was partly extended and the left (LH) MLG door was open but without the MLG being extended. Eventually the aeropla ne landed with partly extended landing gear, without resulting in serious injuries to the occupants. Subsequent investigation revealed t hat the cause of the MLG extension problem was the (partially) blocked hydrau lic return line from the MLG selector valve by pieces of hard plastic. Thes e were identified as parts of the poppet seat of PBSOV Part Number (P/N) 70379 . The PBSOV installed on the incident aeroplane was a modified version of P/N 70379, identified by suffix “A” behind the serial number on the identification plate. This modification was introduced by Eaton, the valve manufacturer, with Eaton Service Bulletin (SB) 70379-32-01 and includes replacement of the original poppet with clamped hard plastic seat by an improved poppet assembly with screwed-on seat. When the affected valve was opened, it was confirmed t hat it contained the improved poppet assembly. The poppet seat fragments f ound in the return system therefore originated from a previously insta lled (pre SB 70379-32-01) P/N 70379 PBSOV and must have been present in the return/pressure line prior to installation ofEASA AD No.: 2009-0220

EASA Form 110 Page 2/2 the modified PBSOV.
This condition, if not detected and correc ted, could lead to further events where the MLG fails to extend, possibly resultin g in loss of control of the aeroplane during landing.
For the reasons described above, this AD requires the inspection of the associated hydraulic lines, irrespective what type PBSOV is installed, removal of contamination in the system, if any, and replacement of each unmodified PBSOV with a modified unit. This AD also prohibits, after installation of a modified PBSOV on an aeropl ane, re-installation of an unmodified PBSOV on that aeroplane.

Effective Date: 28 October 2009

Required Action(s) and Compliance Time(s): Required as indicated, unless accomplished previously:
(1) Within 30 days after the effective date of this AD, inspect the hydraulic lines associated with the PBSOV for the presence of pieces of material from the unmodified P/N 70379 PBSOV poppet seat and, depending on findings, accomplish the necessary corr ective actions before further flight, in accordance with Part 1 of the A ccomplishment Instructions of Fokker Services SBF100-32-159.
(2) Within 18 months after the effect ive date of this AD, re-inspect the hydraulic lines as required by paragra ph (1) of this AD and modify the aeroplane by replacing the unmodified P/N 70379 PBSOV with a modified P/N 70379 PBSOV (identified by suffix “A” behind the serial number on the identification plate) in accordance with Part 2 of the Accomplishment Instructions of Fokker Services SBF100-32-159.
(3) After modification of an aeroplane as required by paragraph (2) of this AD, do not install a P/N 70379 PBSOV on t hat aeroplane, unless the PBSOV has been modified in accordance with Eaton SB 70379-32-01 (identified with suffix “A” behind the serial number on the identification plate).

Ref. Publications: Fokker Services SBF100-32-159 dated 06 October 2009.
The use of later approved revisions of this document is acceptable for compliance with the requirements of this AD.

Eaton Service Bulletin 70379-32-01.

Remarks : 1. If requested and appropriately substantiated, EASA can approve Alternative Methods of Compliance for this AD.
2. The required actions and the risk a llowance have granted the issuance of a Final AD with Request for Comments, postponing the public consultation process after publication.
3. Inquiries regarding this AD should be referred to the Airworthiness Directives, Safety Management & Re search Section, Certification Directorate, EASA. E-mail ADs@easa.europa.eu
4. For any question concerning the tec hnical content of the requirements in this AD, please contact: Fokker Services B.V., Technica l Services Dept., P.O.Box 231, 2150 AE Nieuw-Vennep, The Netherlands; telephone (31) 252-627-350; facsimile (31) 252-627-211; e-mail: technicalservices.fokkerservices@stork.com The referenced publication can be downloaded from www.myfokkerfleet.com