EASA AD US-2021-06-10
Fuel - Refuel Valves / Fueling Shut-off Valve - Master Minimum Equipment List Dispatch Limitations
Summary
Federal Aviation Administration Airworthiness Directive 2021-06-10 is a final rule addressing all Boeing Model 747 and Model 767 series airplanes. It prohibits operation of these aircraft with any inoperative refuel valve (fueling shut-off valve) that has failed in the open position to prevent un-commanded fuel transfer between fuel tanks. This directive responds to a reported unsafe condition involving fuel transfer that could lead to fuel exhaustion.
What Changed
This new airworthiness directive introduces a prohibition on dispatching Boeing 747 and 767 airplanes if any refuel valve is inoperative and stuck open. It removes certain Master Minimum Equipment List (MMEL) dispatch allowances that previously permitted operation with multiple refuel valves failed open. The directive clarifies affected fuel tanks and updates MMEL references, including removing references to models without approved MMELs.
Why It Matters
This directive is critical for aviation professionals as it addresses a safety risk of un-commanded fuel transfer that could cause fuel exhaustion. Operators and maintenance teams must ensure compliance to avoid unsafe flight conditions and regulatory penalties. It impacts dispatch decisions, maintenance scheduling, and MMEL usage for affected Boeing aircraft fleets.
What To Do
Operators of Boeing 747 and 767 series airplanes must ensure no aircraft is dispatched with any refuel valve failed in the open position. Maintenance and compliance teams should review and update procedures to align with the new prohibition and remove reliance on previous MMEL dispatch relief for open refuel valves. The directive is effective April 28, 2021, and compliance must be achieved by that date.
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