U.S. aviation safety officials have asked Boeing Co (BA.N) to provide further analysis and documentation showing that many 737 MAX subsystems would not be affected by reported electrical grounding issues for the first time in three areas of the plane in April, said two people familiar with the matter. Reuters.
The additional analysis introduces new uncertainty about when Boeing’s best-selling airliner would be cleared for flight by the United States Federal Aviation Administration (FAA).
Electrical problems have suspended nearly a quarter of its 737 MAX fleet.
U.S. airlines have said they expect Boeing to issue the service bulletins as early as this week, which would allow them to make fixes and return the planes to service soon, but this latest issue will likely push that deadline back. .
“We continue to work closely with the FAA and our customers to resolve the ground track issue in the affected 737s,” a Boeing spokesperson said.
Asked about the condition of the planes, an FAA spokesperson said “we continue to work with Boeing.”
Airlines withdrew dozens of 737 MAXs from service early last month after Boeing warned of a production-related electrical grounding issue in an emergency power control unit located in the cockpit of some recently built aircraft.
The problem, which also interrupted the delivery of new planes, was then found in two other places of the cockpit, in particular the storage rack where the concerned control unit is located and the dashboard in front of the pilots.
The problem is the latest problem to beset the 737 MAX, which was grounded for nearly two years from 2019 after two fatal crashes.
The series of questions on a relatively simple electrical problem illustrates the tougher regulatory posture that America’s largest exporter faces as it tries to emerge from the overlapping 737 MAX crisis and coronavirus pandemic.
At the end of last week, Boeing submitted service bulletins advising airlines on how to resolve grounding issues or electrical paths designed to maintain safety in the event of a surge, the two said. .
The FAA approved the service bulletins but, as part of ongoing discussions with Boeing, requested further analysis on whether other jet subsystems would be affected by the grounding issue, said the one of the sources. The FAA will review Boeing’s analysis and any necessary revisions to service bulletins before they can be sent to airlines.
Boeing has proposed adding a strap or link cable that workers screw onto two different surfaces creating a grounding path, two people said.
Boeing initially told airlines that a fix could take hours or days per plane.
The electrical grounding issue emerged after Boeing changed a manufacturing method while working to speed up production of the airliner, a third person said. A fourth person said the change improved a hole-drilling process.
The FAA issued a new airworthiness directive last week requiring a fix before the jets resume flight, saying the issue was impacting 109 aircraft in service around the world. Sources said it impacted more than 300 planes in Boeing’s inventory.
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