Airbus A350s must replace a specific part with an improved version

US aviation regulators are requiring certain Airbus A350-1041 airplanes to replace a specific engine part. This rule means airlines must install an improved version of the hydro-mechanical unit, which controls fuel flow to the engine.

Aviation regulators often issue directives to fix known safety issues. This one is notable because it mandates a specific replacement part that was developed and installed in new aircraft after the original problem was identified. This means that older aircraft must now be upgraded to the newer standard, rather than just operating within reduced limits.