AD/B737/214 - Fuselage Skin Lap Joint - Fatigue Cracking (Cth)

COMMONWEALTH OF AUSTRALIA (Civil Aviation Safety Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES

AIRWORTHINESS DIRECTIVE

For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.

Boeing 737 Series Aeroplanes

AD/B737/214 Fuselage Skin Lap Joint - Fatigue Cracking 9/2003 DM

Applicability: Model 737-200, -200C, -300, -400 and -500 series aircraft; line numbers 292 to 2947 inclusive.

Requirement: Action in accordance with the technical requirements of FAA AD 2003-14-06, Amdt 39-13225.

Note: Boeing Service Bulletin 737-53-1179 Revision 2 refers.

Compliance: As specified in the Requirement document, with a revised effective date of 23 July 2003.

This Airworthiness Directive becomes effective on 23 July 2003.

Background: The FAA has received a report of a significant number of cracks along the fuselage skin lap joint of a Boeing 737-300 series aircraft. This aircraft had accumulated 35,710 flight cycles. During scheduled maintenance, fatigue cracks were found on a lap joint that extends from aft of the flight deck to the wing front spar just above the passenger windows. Some of the cracks had linked up to form a 10-inch crack. The cracks were attributed to delaminated skin doublers, due to improper processing during phosphoric anodising. The improperly processed panels were installed on certain aircraft during manufacture and were available to other 737 aircraft models as spare parts.