AD 2010-18-01 Airworthiness Directives; Robert E. Rust, Jr. Model DeHavilland DH.C1 Chipmunk 21, DH.C1 Chipmunk 22, and DH.C1 Chipmunk 22A Airplanes

Models named: DH.C1 Chipmunk 22, DH.C1 Chipmunk 22A. Read the applicability below — it usually turns on serial or part numbers too.

This AD applies to Models DeHavilland DH.C1 Chipmunk 21, DH.C1 Chipmunk 22, and DH.C1 Chipmunk 22A airplanes, all serial numbers, that are certificated in any category. Note: These airplanes are also identified as CHIPMUNK 22A, CHIPMUNK DHC-1T10, CHIPMUNK T.10 MK-22, DH.C1 MK22A, DHC-1, DHC-1 CHIPMUNK, DHC-1 CHIPMUNK 22, DHC-1 SERIES 22, or DHC-1 T.MK. 10.

To address this problem, you must do the following, unless already done:   Actions Compliance Procedures (1) Inspect the flap operating system to identify the P/N of the latch plate installed. If latch plate P/N C1-CF-1489 is installed, inspect the latch plate to determine if it is in compliance with the design standard. An unapproved latch plate P/N C1-CF-1489 is made from two pieces pressed together while one that complies with the design standard is machined in one piece from bar material. Within 50 hours time-in-service (TIS) after October 7, 2010 (the effective date of this AD) or within 90 days after October 7, 2010 (the effective date of this AD), whichever occurs first. Follow de Havilland Support Limited Technical News Sheet (TNS) CT(C1) No 208 Issue 1, dated January 30, 2009. (2) If during the inspection required in paragraph (f)(1) of this AD an unapproved latch plate P/N C1-CF-1489 is found, replace the latch plate with a latch plate that complies with the design standard. The following U.S. standard hardware may be substituted for the hardware specified in the service information: (i) 1/16” diameter cotter pin that is P/N MS24665-153 (or equivalent) in place of split pin P/N SP90/C; and (ii) Washer that is P/N MS15795-806B (or equivalent) in place of washer P/N SP13/B. Before further flight after the inspection where the unapproved latch plate P/N C1-CF-1849 was found. Follow de Havilland Support Limited TNS CT(C1) No 208 Issue 1, dated January 30, 2009. Alternative Methods of Compliance (AMOCs) (g) The Manager, Atlanta Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to ATTN: Carey O'Kelley, Aerospace Engineer, FAA, Atlanta ACO, 1701 Columbia Avenue, College Park, Georgia 30337; telephone: (404) 474-5543; fax: (404) 474-5606. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO. Material Incorporated by Reference (h) You must use de Havilland Support Limited TNS CT(C1) No 208 Issue 1, dated January 30, 2009, to do the actions required by this AD, unless the AD specifies otherwise. (1) The Director of the Federal Register approved the incorporation by reference of this service information under 5 U.S.C. 552(a) and 1 CFR part 51. (2) For service information identified in this AD, contact de Havilland Support Limited, Duxford Airfield, Cambridgeshire, CB22 4QR, England, phone: +44 (0) 1223 830090; fax: +44 (0) 1223 830085; e-mail : info@dhsupport.com; Internet: http://www.dhsupport.com /. (3) You may review copies of the service information incorporated by reference for this AD at the FAA, Central Region, Office of the Regional Counsel, 901 Locust, Kansas City, Missouri 64106. For information on the availability of this material at the Central Region, call (816) 329-3768. (4) You may also review copies of the service information incorporated by reference for this AD at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call (202) 741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. Issued in Kansas City, Missouri, on August 25, 2010. John R. Colomy, Acting Manager, Small Airplane Directorate, Aircraft Certification Service. [FR Doc. 2010-21741 Filed 9-1-10; 8:45 am] BILLING CODE 4910-13-P

This AD results from a report of a latch plate supplied under part number (P/N) C1-CF-1489 failing in service. The part in question was not manufactured to the applicable de Havilland drawing. The unapproved latch plate was made of a shaft that was pressed into a plate, rather than being machined from bar material as one piece. The shaft and plate on the unapproved part can become separated or bent, resulting in rapid wear and failure of the part. This condition, if not corrected, could result in an un-commanded retraction of the flaps. This failure could lead to a stall during a landing approach.