在正常运作下，每个发动机供应热引气到各自的大翼防冰系统。当发生一个系统故障时，交输引气活门打开允许引气穿插两个系统。这保证了大翼防冰维持左右两个系统。Under normal operation, each engine supplies hot bleed air to its own wing anti-ice system. When a system failure occurs, the valve is opened to allow air use between the two systems. This ensures that the wing anti-ice maintenance left and right systems.