Federal aviation regulators issued a new round of safety fixes for Boeing's beleaguered 737 Max jetliners, mandating repairs to sections of the planes that could make them vulnerable to lightning strikes and other activity which might result in engine malfunction.
The proposed fix issued by the Federal Aviation Administration on Tuesday said certain panels on the planes, including the metallic layer that serves as part of the shielding for aircraft wiring, is susceptible to potential "electromagnetic effects of lightning strikes or high intensity radiated fields."
Exposure to such events, the notice of posted to the federal register adds, "could potentially lead to a dual engine power loss event."
The latest FAA airworthiness directive comes less than three months after Boeing issued a service bulletin recommending action be taken on panels that enclose the 737 Max engine nacelles.
Federal aviation officials estimate 128 of the 737 Max airplanes registered in the U.S. could be in need of the safety fixes. But the FAA said it is not certain Boeing's bulletin includes all the airplanes impacted by "the unsafe condition." Therefore, the FAA is expanding its mandate to include all Max aircraft in Boeing's fleet.
The aerospace manufacturer said in December that "the protective foil inside the composite panels may have gaps" on aircraft produced between February 2018 and June 2019.
A spokesperson for Boeing said the company is coordinating with customers to finish the work ahead of the Max jet's return to service.
It remains unclear when the Max will return to service.
The planes have been grounded worldwide since March following a pair of deadly crashes – a Lion Air flight off the coast of Indonesia in 2018 and an Ethiopian Airlines flight in 2019 – that killed a combined 346 people.
Boeing halted production of the Max aircraft, which had been its best-selling plane, in December amid a realization that federal officials would not grant a swift return to service.
The grounding and ceasing production have had ripple effects throughout Boeing's supply chain. This includes last month's announcement by Wichita-based Spirit AeroSystems that it was laying off 2,800 employees due to uncertainty over when Boeing would resume production of the plane.
Boeing said in a January statement that the company estimates FAA and global regulators would proceed with the "ungrounding" of the 737 Max sometime in mid-2020.