Credit: American AirlinesWASHINGTON—An FAA order mandating changes to Boeing 737 MAXs affected by recently discovered electrical issues before those aircraft can fly again has been finalized and is slated for publication April 30.
The immediately-effective airworthiness directive (AD) orders affected 737-8 and 737-9 operators to modify electrical bonding of the P6 panel, “including the mounting tray for the standby power control unit (SPCU),” as well as the bonding of the main instrument panel (MIP) assembly in front of and between the two pilot seats.
Specific modification instructions will be detailed in two Boeing-developed service bulletins referenced in the AD that the FAA still must approve. It is not clear when the service bulletins will be finalized.
“We have been working closely with the FAA and our customers to finalize two service bulletins that will ensure a sufficient ground path in those areas,” Boeing said in a statement. “Upon FAA approval, we will provide the final versions of the bulletins to affected operators with detailed instructions on completing the work to return their airplanes to service.”
The issues were traced to “manufacturing design changes to certain metallic support panel assemblies installed in the flight deck,” the FAA AD said. “The design changes resulted in insufficient bonding of the panel assemblies and consequent insufficient electrical grounding of installed equipment ... [W]ithout dedicated grounding paths implemented by design, there is a potential for degradation or loss of the existing uncontrolled ground paths on those airplanes over time.”
The issues, revealed earlier in April, affect 737 MAX aircraft with line numbers from 7399 through 8082. FAA said 106 of these are with 21 operators, including about 90 that were in active service following the model’s return from a 21-month grounding. Some are in countries that have not approved the 737 MAX’s return from the grounding, including China and India.
The AD calls on affected operators to make the Boeing-specified modifications “before further flight.” Once finalized, the modifications are expected to take no more than three days per aircraft.
An April 27 report by The Air Current said the proposed modifications include adding 20 ground studs and six jumpers in the P6 panel, which sits behind the right-side pilot seat, and five studs and six jumpers on the MIP. Aviation Week confirmed The Air Current’s report.
Boeing also must modify some 370 737 MAXs it has built since early 2019 but not delivered. The company, which is prioritizing 737 MAX deliveries as a key to its financial turnaround, has handed over four 737 MAXs in April after averaging about 19 per month in the first quarter.
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