Boeing said Tuesday it has discovered yet another manufacturing quality flaw on the 787 Dreamliner — this time in an attachment fitting inside the horizontal tail, referred to as the stabilizer — that will delay deliveries of the jet as mechanics work to fix the defect.
"We are inspecting 787s in our inventory for a nonconforming condition related to a fitting on the horizontal stabilizer," Boeing said in a statement. "The inspections and required rework will affect timing of near-term 787 deliveries."
The statement added that the defect in the tail is "not an immediate safety of flight issue and the in-service fleet may continue to operate."
It's the latest in a long and very expensive litany of 787 quality woes.
The affected attachment fitting is provided by a supplier and installed on the horizontal tail at Boeing's manufacturing facility in Salt Lake City.
The defect is a small, paper-thin gap in the attachment, Boeing said. Such gaps are typically plugged using a filler known as a shim. The shims in the attachment were incorrectly sized so that the gap exceeded the five-thousandths of an inch allowable in the specification.
In April, Boeing discovered a flawed fitting inside the vertical tailfin of a different jet, the 737 Max. In that case, "a nonstandard manufacturing process" affected two out of eight fittings that attached the tailfin to the fuselage.
Repairs of that flaw are taking months per airplane.
With this new defect on the 787 horizontal tail, Boeing has not yet clarified exactly what it is that the fitting attaches to.
Boeing said that while its engineering team is still finalizing the repair plan, it expects that completing the rework could take a couple of weeks per airplane.
"Airplanes found to have a nonconforming condition will be reworked prior to ticket and delivery," Boeing said. "We have notified the FAA and our customers and are keeping them informed of our progress."
Last Friday, Boeing suspended ticketing of 787s required as clearance for delivery, pending inspections and any needed repairs on each aircraft.
Starting in the fall of 2020, Boeing found previous quality defects at multiple joins inside 787 fuselages that stopped almost all deliveries of the jet through August 2022, racking up more than $6.3 billion in additional "abnormal costs."
Mechanics in Everett and in North Charleston, S.C. are still working laboriously through those fixes on stored aircraft.
A separate documentation glitch temporarily halted 787 deliveries in February.
This isn't even the first shimming flaw to affect the horizontal tail in Salt Lake City.
In the fall of 2020, Boeing found that certain components within the horizontal tail had been "clamped together during the build process with greater force than specified," leaving potential gaps wider than the specification.
Boeing's technical team is checking manufacturing records and inspecting the 787s stored in inventory to determine how many of those now will need this new tail defect fixed, in addition to the repairs at the fuselage joins, before they can be delivered to airline customers.
Pending further analysis, Boeing said that "at this time" it doesn't expect to cut the 70 to 80 deliveries of the 787 it had previously projected for this year.
©2023 The Seattle Times. Visit seattletimes.com. Distributed by Tribune Content Agency, LLC.
