AD 99-10-13 Airworthiness Directives; Boeing Model 737-300, -400, -500, -600, -700, and -800 Series Airplanes Equipped with Vickers Combined Stabilizer Trim Motors

Models named: 737-300, -400, -500, -600, -700, -800 series. Read the applicability below — it usually turns on serial or part numbers too.

Model 737-300, -400, -500, -600, -700, and -800 series airplanes, certificated in any category; equipped with Vickers combined stabilizer trim motors. Note 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (e) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Required as indicated, unless accomplished previously. To prevent failure of the trailing edge flap limit switch, which could result in uncommanded (nose down) stabilizer trim motion and reduced controllability of the airplane, accomplish the following: Inspections and Tests (a) Perform a special detailed inspection and functional test to verify proper operation of the S245 trailing edge flap limit switch, in accordance with the applicable Boeing Alert Service Bulletin 737- 27A1227 (for Model 737-300, -400, and -500 series airplanes) or 737- 27A1228 (for Model 737-600, -700, and -800 series airplanes), both dated April 8, 1999; as applicable; at the time specified in paragraph (a)(1) or (a)(2) of this AD, as applicable. (1) For airplanes that have accumulated less than 1,000 total flight hours as of the effective date of this AD: Inspect and test prior to the accumulation of 1,000 total flight hours, or within 10 days after the effective date of this AD, whichever occurs later. Repeat the inspection and test thereafter at intervals not to exceed 300 flight hours, until accomplishment of paragraph (c) of this AD. (2) For airplanes that have accumulated 1,000 or more total flight hours as of the effective date of this AD: Inspect and test within 5 days after the effective date of this AD. Repeat the inspection and test thereafter at intervals not to exceed 300 flight hours, until accomplishment of paragraph (c) of this AD. Note 2: Any inspection and test of the S245 trailing edge flap limit switch accomplished prior to the effective date of this AD in accordance with the Accomplishment Instructions of either Boeing Alert Service Bulletin 737-27A1227 (for Model 737-300, -400, and - 500 series airplanes) or 737-27A1228 (for Model 737-600, -700, and - 800 series airplanes), both dated April 8, 1999, as applicable, is considered acceptable for compliance with the initial inspection and test specified in paragraph (a) of this AD. Corrective Action (b) If any malfunction is detected during any inspection and test required by paragraph (a) of this AD, prior to further flight, replace the existing limit switch with a new limit switch in accordance with the Boeing Alert Service Bulletin 737-27A1227 (for Model 737-300, -400, and -500 series airplanes) or 737-27A1228 (for Model 737-600, -700, and -800 series airplanes), both dated April 8, 1999, as applicable. Repeat the inspection and test thereafter at intervals not to exceed 300 flight hours, until accomplishment of paragraph (c) of this AD. (c) Within 3 months after the effective date of this AD: Incorporate an improved design of the stabilizer control system in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. Incorporation of an improved design, as required by this paragraph, constitutes terminating action for the repetitive inspection and test requirements of this AD. Reporting Requirement (d) Within 10 days after accomplishing the inspection and test required by paragraph (a) of this AD, submit a report of the inspection and test results (positive findings of malfunctioning only) to the Manager, Seattle ACO, FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, Washington, 98055-4056. The report must include the inspection results, the airplane serial number, and the total number of landings and flight hours on the airplane. Information collection requirements contained in this regulation have been approved by the Office of Management and Budget (OMB) under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-0056. Alternative Methods of Compliance (e) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle ACO. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO. Note 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. Special Flight Permits (f) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished. Incorporation by Reference (g) Except as provided by paragraph (c) of this AD, the actions shall be done in accordance with Boeing Alert Service Bulletin 737- 27A1227, dated April 8, 1999; or Boeing Alert Service Bulletin 737- 27A1228, dated April 8, 1999; as applicable. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. (h) This amendment becomes effective on May 27, 1999. Issued in Renton, Washington, on May 4, 1999. D.L. Riggin, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 99-11783 Filed 5-11-99; 8:45 am] BILLING CODE 4910-13-P