Airworthiness Directive · Amendment 39-11844 · Boeing Model 737-100, -200, and -200C Series Airplanes
Boeing Model 737-100, -200, and -200C Series Airplanes
Model 737-100, −200, and −200C series airplanes; line numbers 1 through 315 inclusive, 323, and 324; 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 (d) 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.
This amendment adopts a new airworthiness directive (AD) that is applicable to certain Boeing Model 737-100, -200, and -200C series airplanes. This action requires inspections of a certain component, and corrective action, if necessary. This action is necessary to detect and correct stress corrosion cracking in the front spar of the center section of the horizontal stabilizer, which could result in structural failure of the horizontal stabilizer and loss of control of the airplane. This action is intended to address the identified unsafe condition.
To detect and correct stress corrosion cracking in the front spar of the center section of the horizontal stabilizer, which could result in structural failure of the horizontal stabilizer and loss of control of the airplane, accomplish the following:
(a) Within 90 days after the effective date of this AD, perform a detailed visual inspection to detect cracks in the front spar of the center section of the horizontal stabilizer, in accordance with Boeing Alert Service Bulletin 737-55A1071, dated
February 24, 2000. Thereafter, repeat the inspection twice more at intervals not to exceed 200 days, and thereafter at intervals not to exceed 24 months or 4,000 flight cycles, whichever occurs first.
Note 2: For the purposes of this AD, a detailed visual inspection is defined as: “An intensive visual 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 intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.”
(b) Except as required by paragraph (c) of this AD, if any crack is detected during any inspection required by paragraph (a) of this AD, prior to further flight, accomplish rework of the front spar of the center section of the horizontal stabilizer (including removing damaged material, accomplishing a high frequency eddy current inspection to detect cracking, and shot peening the damaged area), in accordance with Boeing Alert Service Bulletin 737-55A1071, dated February 24, 2000.
(c) If any crack that is outside the limits specified in the alert service bulletin is detected during any inspection required by paragraph (a) of this AD, prior to further flight, repair in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate; or in accordance with data meeting the type certification basis of the airplane approved by a Boeing Company 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.
