Inspections prompted by manufacturing missteps within Boeing Co.'s Dreamliner program are slowing deliveries for new aircraft, adding to complications brought on by the coronavirus pandemic.
Eight affected 787 jets were temporarily pulled from service late last month after the planemaker identified two flaws in their aft-body sections that were made at its factory in North Charleston.
The company confirmed Tuesday that it has found another production issue with the 787 that could cause delays, this time involving a wing-like flight-control component called the horizontal stabilizer that goes at the rear of the plane.
"We are taking time to thoroughly inspect completed 787s to ensure that they are free of the issues and meet all engineering specifications," Boeing said in a statement. Those inspections will affect the timing of Dreamliner deliveries in the "near-term," Boeing said.
Final assembly and deliveries for the Dreamliner program are split between production sites in North Charleston and Everett, Wash.
The horizontal stabilizer is made at a Boeing factory in Salt Lake City, Utah. In a statement Tuesday, the company said the issue occurred when some components of the part were "clamped together with greater force" than they should have been.
That could cause that section of the plane to age prematurely, Boeing said, but doesn't create an immediate flight-safety issue. The company said none of the affected jets in service "are within a window where they could begin to experience this aging," but Boeing is looking into whether it needs to take action on the in-service fleet.
The issue with the Salt Lake City-made part is separate from the production flaws that took eight Dreamliners out of service a couple of weeks ago. Those groundings were related to issues with improper spacing in the place where two sections are joined on some 787 jets.
United, Air Canada and Singapore Airlines were among the carriers that own one of the 787s taken out of service.
Boeing South Carolina workers assemble aft-body sections for the 787 in North Charleston. Production issues with the jetliner have further slowed deliveries, the company says. File/Staff
All tail sections for the program, including those for Dreamliners assembled on the West Coast, are made at the South Carolina factory. In the eight grounded jets, two flaws were found within the aft-body sections of the planes that, together, made them unsafe to fly until the issues were corrected.
One of those flaws involved an issue with the smoothness of the fuselage's inner skin. There are "very tight tolerances" for the flatness of that skin, Boeing said, and any variances greater than about the width of a human hair don't meet engineering standards.
"In many cases, engineering analysis can show that the variation has no effect on structural integrity but this finding must be documented to remain in compliance with our approved processes," the company said.
The skin flatness issue also affected several undelivered 787s, Boeing said, and the completed jets sitting at its factories are being inspected to "ensure every one of them meets all engineering design specifications."
The Federal Aviation Administration is investigating the production issues.
According to a Wall Street Journal report Monday that cited an internal FAA memo and unidentified sources, the review is considering requiring "enhanced or accelerated inspections" on as many as 900 Dreamliner jets.
The FAA said in its statement that it is "too early to speculate" about any of the airworthiness directives that could come out of its probe.
Boeing's South Carolina plant was recently called out by the FAA for alleged violations of a program that allows the company to inspect its own aircraft and issue airworthiness certificates. In letters sent to Boeing early last month, the agency detailed claims that deadline-driven managers at the plant had put "undue pressure" on its safety workers.
The North Charleston plant also faced widespread scrutiny last year after claims of shoddy production work at the site, and Boeing's overall safety practices have been closely watched since the first of two deadly 737 Max crashes occurred almost two years ago, in October 2018.
The continued grounding of the Max, combined with the ongoing financial strain caused caused by the COVID-19 pandemic, has driven down the planemaker's order and delivery totals this year and led to thousands of layoffs companywide.
That trend continued in August when cancellations continued to outpace new airplane orders.
Just four Dreamliners were delivered last month. The deliveries were split evenly between Charleston and Everett, according to a spreadsheet from the blog All Things 787.
That brings the delivery total for the program this year to 42. At this time last year, 101 Dreamliners had been delivered.
A list of eight new orders logged in August included a few 777 cargo planes for the Taiwanese carrier Eva Air. The airline is swapping out freighters and smaller Dreamliners for 787-10s it had on order.
That's a setback for the North Charleston plant, which is the only site that can build the 787-10, the largest of the three models. Eva Air originally booked an order for 18 of the "Dash 10" jets, but it will be exchanging seven of them for four 787-9s and three 777s.
Like other airlines, Eva reported a steep decline in passenger flights last quarter, about 94 percent, but made up for some of its losses during the pandemic with increased income from cargo services.