Hot on the heels of the Federal Aviation Administration (FAA) issuing an Airworthiness Directive concerning potential corrosion affecting Boeing’s 737 MAX engines, Boeing is also being asked to provide proof multiple subsystems on the aircraft would not be affected by the electrical grounding issues that have seen nearly 25% of the worldwide 737 MAX fleet grounded.
Another setback for the 737 MAX
It is a setback for the Boeing 737 MAX program and the airlines that fly the plane. Reports had suggested airlines were expecting service bulletins addressing the grounding issues imminently. That now looks unlikely to happen.
After clearing the aircraft to fly in November 2020 after a twenty-month grounding, this second grounding (albeit not impacting the entire 737 MAX fleet) is putting added pressure on Boeing.
After successfully re-entering United States skies and taking some blockbuster orders over the northern 2020/21 winter, Boeing’s 737 MAX looked to be back on track. But in early April, Boeing flagged a potential electrical issue in a specific group of 737 MAX aircraft. Boeing “recommended” 16 airlines sort the problem before letting the planes back into the sky.
Boeing was concerned about the electrical grounding inside a backup power control system. However, there were hopes for a relatively swift fix. A week or two into the grounding, affected airlines were relatively confident their grounded MAXs would soon be flying again.
Between them, United Airlines, Southwest Airlines, and American Airlines grounded more than 60 of their 737 MAXs. In April, the airlines were saying they knew what the problem is. They also said they knew what needed to be done about it, and how swiftly the issue could get fixed.
Timelines to return grounded 737 MAXs to service now likely pushed back
But overnight, Reuters reported Boeing is facing further hurdles regarding the grounding. Previously, the FAA has said “subsequent analysis and testing” showed the issue could involve additional systems. Systems flagged include the standby power control unit, a circuit breaker panel, and the main instrument panel.
Now, according to Reuters who cite two sources “familiar with the matter,” US safety regulators want additional documentation and analysis to show the grounding problem originally flagged by Boeing is not affecting other systems on the aircraft.
That indicates the FAA is still someway from drawing a line under the latest drama impacting the 737 MAX. It also suggests US airline bosses may have to cool their heels a while longer than originally planned.
Current 737 MAX grounding impacts nearly 25% of the worldwide fleet
In addition to the three United States-based airlines, other airlines with grounded MAX aircraft include Cayman Airways, Copa Airlines, GOL Linhas Aereas, Icelandair, Minsheng Leasing, Neos Air, Shandong Airlines, SilkAir, SpiceJet, Sunwing Airlines, TUI, Turkish Airlines, Valla Jets Limited, WestJet Airlines, and Xiamen Airlines. All up, over 100 MAXs are on the ground. As of March 31, Boeing had delivered 472 MAXs to customers worldwide.
Meanwhile, the FAA issued an Airworthiness Directive on Tuesday concerning possible corrosion in some Boeing 737 MAX CFM LEAP-1B engines. The corrosion may have occurred as a consequence of long-term storage.
According to the FAA, there have been multiple reports of pressure sub-system (PSS) unit faults due to corrosion following storage. This can lead to reduced thrust. While not immediately dangerous it does require attention from operators.