The Federal Aviation Administration (FAA) on Wednesday finalized a directive requiring airlines to complete inspections of a key component of Boeing 737 MAX airplanes that, if faulty, could result in a loss of power to the engines.


The FAA, in response to a service bulletin issued by Boeing in December, proposed an airworthiness directive in February to mandate inspections.The directive addressed concerns that some 737 MAX exterior panels on top of the engine may not have electrical bonding necessary to ensure adequate shielding of underlying wiring from the electromagnetic effects of high-power radio frequency transmitters and other sources.


That, the FAA warned, “could potentially lead to a dual-engine power loss event and/or display of hazardously misleading” data. The agency added that the issue could result in a “forced off-airport landing.”


The 737 MAX, Boeing’s best-selling plane, has been grounded since March 2019, after crashes in Indonesia and Ethiopia killed 346 people.


Boeing said it supports “the FAA’s airworthiness directive, which makes our recommended action mandatory” to address the possible impact of electrical energy on the plane.


The FAA said in February the directive would also address the potential safety risks of lightning strikes, but Boeing told the agency that was not accurate. The FAA agreed in its final directive to remove the reference to lightning, saying it had conducted further analysis since February.


Boeing said in December the issue affected airplanes built between February 2018 and June 2019, and as a result “the protective foil inside the composite panels may have gaps.”


After the inspections, airlines will replace any excessively reworked panels and modify an assembly to ensure adequate electrical bonding.


Reuters reported on June 10 that Boeing is aiming to conduct a key flight certification test in late June. That test could take place as early as next week or could be set for early July, a person briefed on the matter said.