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AD/F100/71 - Main Landing Gear Bay Fuel/Hydraulic Lines
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AD/F100/71 - Main Landing Gear Bay Fuel/Hydraulic Lines
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| AD/F100/71 | Main Landing Gear Bay Fuel/Hydraulic Lines | 11/2005 |
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| Applicability: | Fokker Aircraft B.V. Model F28 Mark 0070 and Mark 0100 aeroplanes. |
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| Requirement: | 1. Inspect the clearance between the fuel lines and hydraulic lines in the left hand (LH) and right hand (RH) main landing gear (MLG) Bays in accordance with Section 3 of the accomplishment instructions, Part 1, of Fokker Service Bulletin (SB) F100-28-041 dated 20 July 2005 or later CAA-NL approved revision and when clearances between the affected lines are found of 3 mm (0.118 inch) or more in both MLG Bays, no further action is required and the aircraft may be returned to service.(a) When a clearance between the affected lines is found of less than 3 mm (0.118 inch) and there are chafing marks on the fuel lines, replace the affected fuel line and modify or readjust, as applicable, the attachment of the affected fuel lines and hydraulic lines in accordance with Section 3 Accomplishment Instructions, Part 2, of Fokker SB F100-28-041 or later CAA-NL approved revision.(b) When a clearance between the affected lines is found of less than 3 mm (0.118 inch) and there are no chafing marks on the fuel lines, modify or readjust, as applicable, the attachment of the affected fuel lines and hydraulic lines in accordance with Section 3 Accomplishment Instructions, Part 2, of Fokker SB F100-28-041 or later CAA-NL approved revision.Note: CAA-NL AD NL-2005-010R1 EASA approval No. 2005-6232 dated7 September 2005 refers. |
| Compliance: | 1. Within the next 6 months after the effective date of this directive.(a) Before further flight.(b) Within the next 6 months after the inspection as required by Requirement 1(a) of this Directive. |
| This Airworthiness Directive becomes effective on 27 October 2005. |
| Background: | During regular operations with a Fokker 100 (F28 Mark 0100), a fuel leak was found in the LH MLG Bay. The subsequent investigation revealed that a fuel line was chafed through, caused by interference with a hydraulic line. During manufacturing of the aircraft, a minimum distance of three (3) mm (0.118 inch) was maintained between fuel and hydraulic lines. During operation of the aircraft or during the accomplishment of maintenance tasks, loads induced on these lines can reduce this distance sufficiently enough to cause interference between them. Interference between fuel lines and hydraulic lines can ultimately result in sufficient wear to the fuel lines to cause a fuel leak. This condition, if not corrected, could lead to further cases of fuel leakage in the MLG Bay, in the vicinity of hot brakes, potentially resulting in a MLG Bay fire. Since an unsafe condition has been identified that may exist or develop on aircraft of the same type design, this Airworthiness Directive requires a one-time inspection of the clearance between the fuel lines and hydraulic lines in the LH and RH MLG Bays and, if necessary, corrective action. |
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James Coyne
Delegate of the Civil Aviation Safety Authority
15 September 2005