The entities have expanded the scope of their reviews of the “aft pressure bulkhead structure on the 737 Max 8”, and are examining hand-drilled fasteners, Washington-based The Air Current reported.
“The newly expanded X-ray inspections and rework risk further slowing both the recovery progress and the pace of overall production as Boeing seeks to accelerate output,” the report said.
The National reached out to Boeing to confirm the development.
“We continue to take the time necessary to ensure each airplane meets our standards and regulatory requirements prior to ticketing and delivery,” Boeing told The National, without divulging further details.
Kansas-based Spirit is one of the world’s largest manufacturers of aerostructures for commercial planes, defence platforms, and business or regional jets. The aerostructure is a component of an aircraft's airframe.
In August, Boeing said a production glitch, found recently in some of its 737 Max jets, was not a safety risk but would lead to delivery delays for its best-selling model.
The defect was discovered after Spirit drilled “elongated” fastener holes in the aft pressure bulkhead in a way that did not confirm to specifications, the Virginia-based plane maker said.
The aft pressure bulkhead is a dome-shaped structural wall at the rear of the fuselage that is responsible for maintaining passenger cabin pressure in the aircraft.
Boeing said in July that its 737 programme had set a production target of 38 aircraft a month and planned to reach 50 a month in the 2025-2026 time frame. The company expects to deliver 400 to 450 jets in 2023.
The recent issue tops off a long history of problems for the 737 Max. The jet was grounded by regulators worldwide after crashes in Indonesia and Ethiopia in 2018 and 2019.
It returned to service in the US in November 2020 after a 20-month span, during which Boeing made software upgrades and training changes.
Other countries then resumed 737 Max flights after conducting regulatory inspections.
Boeing, which has struggled to increase aircraft production as travel demand rebounds in the pre-coronavirus era, reported a net loss of $149 million in the second quarter due to delays and cost issues in its defence and space programme
However, revenue in the April-June period rose 18 per cent annually to more than $19.7 billion.