COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Fokker F28 Series Aeroplanes AIRWORTHINESS DIRECTIVE For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/F28/81 and issues the following AD under subregulation 39.1 (1) of CAR 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. AD/F28/81 Amdt 1 MLG Attachment Bracket 3/2001 Applicability: Model F28 Mk. 1000 through Mk. 4000 series, serial numbers 11003 through 11091, 11094 through 11171, 11991, and 11192. Requirement: 1. Inspect the affected area of the upper girder of the MLG bracket and wing stringer fitting in accordance with Parts 2A and 2B of the Accomplishment Instructions of Fokker Service Bulletin (SB) F28/57-90 Revision 1, dated August 28, 2000. 2. If no cracks were found as a result of the inspection required by the original issue of this Directive, re-inspect in accordance with Requirement 1. 3. If cracks are found, before further flight, accomplish temporary repairs, and thereafter, depending on crack length, as applicable, perform repetitive inspections at the times specified in Table 1 of this Directive; in accordance with Part 3 of the Accomplishment Instructions of Fokker SB F28/57-90 Revision 1. Note 1: Replacement of the MLG bracket must be done in accordance with Fokker SB F28/57-92. Note 2: RLD AD 1999-045/2 refers. Compliance: For Requirement 1 and 2: Within 12 months after 22 March 2001. Thereafter at intervals not to exceed 18 months. For Requirement 3: As per Table 1 below: COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES TABLE 1 Crack Length Repair Instruction Repeat Insp. Interval Less than 3 mm. Install concentric bushing* 18 months Greater than 3mm, less than 7mm. Install eccentric bushing* 18 months Greater than 7mm, less than 15 mm. Remove cracked part and accomplish repairs* 18 months Greater than 15 mm, less than 25 mm. Greater than 25 mm, less than 40 mm. As above 250 flight cycles or 1 month As above 50 flight cycles or 1 week Greater than 40mm. Replace MLG bracket * As an alternative to the above repair action, the MLG bracket may be inspected at intervals not to exceed 250 flight cycles or 1 month, whichever occurs first. This amendment becomes effective on 22 March 2001. Background: The RLD received a number of reports from F28 operators of cracks discovered in the upper girder of the main landing gear (MLG) bracket, between the stringer fitting bolts, attaching the MLG bracket and fitting to the wing upper skin. Crack surface investigation has shown that the cracking occurred due to stress corrosion. Amendment 1 is issued in response to a revised RLD AD which introduces repetitive inspections as a result of original inspection findings. The original issue of this Airworthiness Directive became effective on 15 July 1999. David Alan Villiers Delegate of the Civil Aviation Safety Authority 8 February 2001 The above AD is notified in the Commonwealth of Australia Gazette on 21 February 2001.