EASA AD CF-2017-05R2
Fuel System — Motive Flow Line Fouling, Motive Flow Line and Pressure Relief Line Broken P-Clamps, and Vent Line TeflonTM Sleeve Installation
Summary
The Canadian Airworthiness Directive CF-2017-05R2 titled 'Fuel System — Motive Flow Line Fouling, Motive Flow Line and Pressure Relief Line Broken P-Clamps, and Vent Line TeflonTM Sleeve Installation' applies to De Havilland DHC-8-400 series aircraft with serial numbers 4001, 4003, and subsequent. It addresses issues related to broken P-clamps on fuel system lines, interference causing wear on the motive flow line, and improper installation of Teflon sleeves on vent lines that could lead to fuel tank ignition risks during lightning strikes.
What Changed
This revision CF-2017-05R2 updates previous directives by adding requirements to inspect and reposition Teflon sleeves on vent lines, introduces additional serial numbers in applicability, mandates incorporation of airworthiness limits in maintenance programs, prohibits certain maintenance procedures, and updates references to Bombardier service bulletins. It supersedes the earlier CF-2017-05R1 issued in 2017.
Why It Matters
The directive is critical for operators and maintenance organizations to prevent fuel tank ignition caused by electrical arcing due to damaged clamps or improperly installed insulation. Compliance ensures the structural integrity and electrical isolation of fuel system components, reducing safety risks associated with lightning strikes. It also affects maintenance scheduling and procedures, requiring adherence to updated service instructions.
What To Do
Operators must comply by inspecting, modifying, or replacing affected fuel system components within specified flight hours or calendar months from the directive's effective dates. This includes enlarging fuel tank bulkhead holes, replacing broken P-clamps, verifying proper support and clearance of fuel lines, and correctly installing or repositioning Teflon sleeves on vent lines. Maintenance programs must incorporate new airworthiness limits and avoid prohibited tasks as outlined.
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