Boeing Co. issued two maintenance bulletins to 18 airlines concerning repairs to the electrical grounding issue discovered earlier this year on 737 MAX jets. All of the aircraft have been grounded since early April, and the repair have been authorized by Federal Aviation Administration. Boeing also halted deliveries of new 737 MAX jets as it determined the source of the problem.
Boeing identified three similar electrical grounding issues – one in a cockpit back-up power control unit, and similar problems in the control unit’s storage rack and instrument panel. All the affected airlines had been manufactured recently, following a change in 737 MAX production processes implemented to increase productivity.