AIRWORTHINESS DIRECTIVE

CAA-AD-078/2001

Date of issue: August 31, 2001

AIRCRAFT - FRONT AND REAR SPARS OF WING - INSPECTION

Applicability: Model 737-100 and -200 series airplanes, line number 1 through 310 inclusive, and 323; certificated in any category.

Effective date: October 04, 2001

Compliance: Required as indicated in FAA AD 2001-16-06.

Remarks: The compliance of this AD must be recorded in Aircraft Logbook, where applicable the requirements of this AD must be integrated into Aircraft Technical Documentation. Address inquiries concerning this AD to: Civil Aviation Authority, Airworthiness Division, Ruzyne Airport, 160 08 Prague 6, Czech Republic, tel: 420 2 33320922, fax: 420 2 20562270.

Ing. Pavel MATOUŠEK

Director of Airworthiness Division

CAA CZ

2001-16-06 Boeing: Amendment 39-12374. Docket 99-NM-367-AD.

Applicability: Model 737-100 and -200 series airplanes, line number 1 through 310 inclusive, and 323; certificated in any category.

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 (g) 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.

Compliance: Required as indicated, unless accomplished previously.

To detect and correct cracking or corrosion of the upper and lower chords of the front and rear spars of the wing, which could result in reduced structural integrity of the wing, accomplish the following:

Initial Detailed Visual and Eddy Current Inspections (Part I)

(a) Within 12 months after the effective date of this AD: Do an initial detailed visual inspection to detect cracking or corrosion of the upper and lower chords of the front and rear spars, and an eddy current inspection to detect cracking of the vertical legs of the upper chords of the front and rear spars, per Part I of the Accomplishment Instructions of Boeing Service Bulletin 737-57-1067, Revision 4, dated November 7, 1991. Before further flight following the inspections, do the follow-on corrective actions required by paragraph (d) of this AD.

Note 2: For the purposes of this AD, a detailed visual inspection is defined as: ``An intensive examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate by the inspector. Inspection aids such as mirrors, magnifying lenses, etc. may be used. Surface cleaning and elaborate access procedures may be required.''

Repetitive Detailed Visual and Eddy Current Inspections (Part II)

(b) Repeat the initial detailed visual inspection required by paragraph (a) of this AD at intervals not to exceed 12 months per Part II of the Accomplishment Instructions of Boeing Service Bulletin 737-57-1067, Revision 4, dated November 7, 1991. Before further flight following the inspection, do the follow-on corrective actions required by paragraph (d) of this AD.

(c) Repeat the initial eddy current inspection required by paragraph (a) of this AD at intervals not to exceed 48 months per Part II of the Accomplishment Instructions of Boeing Service Bulletin 737-57-1067, Revision 4, dated November 7, 1991. Before further flight following the inspection, do the follow-on corrective actions required by paragraph (d) of this AD.

Follow-on Corrective Actions (Parts I, II, and III)

(d) Do the follow-on corrective actions (including cleaning spar cavities, removing corrosion, and applying corrosion-inhibiting compound) required by paragraphs (d)(1), (d)(2), (d)(3), and (d)(4) of this AD, as applicable.

(1) If no cracking or corrosion is found, apply a corrosion-inhibiting compound to the accessible areas of the upper and lower chords of both the front and rear spars per Part I or Part II of the Accomplishment Instructions of Boeing Service Bulletin 737-57-1067, Revision 4, dated November 7, 1991, as applicable.

(2) If any corrosion is found, repair per Part III of the Accomplishment Instructions of Boeing Service Bulletin 737-57-1067, Revision 4, dated November 7, 1991.

(3) If a horizontal crack is found in the upper chords of the front or rear spars, repair per paragraph (f) of this AD.

(4) If any cracking is found other than that identified in paragraph (d)(3) of this AD, repair per paragraph (d)(4)(i) or (d)(4)(ii) of this AD, as applicable.

(i) If damage of the chords of the front or rear spar is within the limits specified in the service bulletin, before further flight, repair per Part III of the Accomplishment Instructions of Boeing Service Bulletin 737-57-1067, Revision 4, dated November 7, 1991.

(ii) If damage of the chords of the front or rear spar exceeds the limits specified in the service bulletin, before further flight, repair per paragraph (f) of this AD.

Initial and Repetitive Eddy Current Inspections of Previous Repairs

(e) For airplanes on which a previous repair to the upper chord of the front or rear spar was made per Boeing Service Bulletin 737-57-1067, Revision 3, dated May 24, 1990, or earlier revisions: Within 12 months after the effective date of this AD, do an eddy current inspection of the repair area to detect cracking per a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA. Repeat this inspection thereafter at intervals not to exceed 12 months. If any discrepancy is found, before further flight, repair per paragraph (f) of this AD. For a repair method to be approved by the Manager, SACO, as required by this paragraph, the approval letter must specifically reference this AD.

Repair

(f) Repair (including removing corrosion; inspecting the rework area for cracks; refinishing the blend-out area; installing a nesting angle repair; and applying chemical film treatment, primer, sealant, and corrosion-inhibiting compound) any discrepancy specified in paragraphs (d)(3), (d)(4)(ii), and (e) of this AD, per a method approved by the Manager, Seattle ACO; or per data meeting the type certification basis of the airplane approved by a Boeing Designated Engineering Representative who has been authorized by the Manager, Seattle ACO, to make such findings. For a repair method to be approved by the Manager, Seattle ACO, as required by this paragraph, the approval letter must specifically reference this AD.

Alternative Methods of Compliance

(g) 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, FAA. 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

(h) 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

(i) Except as provided by paragraphs (e) and (f) of this Ad, the actions shall be done in accordance with Boeing Service Bulletin 737-57-1067, Revision 4, dated November 7, 1991. 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.

Effective Date

(j) This amendment becomes effective on September 24, 2001.

Issued in Renton, Washington, on August 9, 2001.

Vi L. Lipski,

Manager, Transport Airplane Directorate, Aircraft Certification Service.

[FR Doc. 01-20697 Filed 8-17-01; 8:45 am]

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