The U.S. Federal Aviation Administration are investigating manufacturing flaws over some Boeing 787 Dreamliners.
Earlier today, Boeing disclosed a new manufacturing quality issue with the 787 Dreamliner, this time with assembly of the airplane’s horizontal tail in Salt Lake City. The disclosure comes after last week’s revelations of quality control problems at Boeing’s South Carolina plant affecting the 787’s aft fuselage.
Boeing also released data Tuesday showing the tally of lost 737 MAX orders this year is now approaching 1,000 jets.
During fabrication in Salt Lake of the 787’s horizontal tail — known as the stabilizer — engineers discovered earlier this year that “certain components were clamped together during the build process with greater force than specified,” potentially leaving the structure with gaps between components wider than the allowable specification, Boeing said.
This flaw, which Boeing said was identified during an internal audit conducted in February, “may lead to premature aging of the part,” meaning the horizontal tail structure.
Boeing spokesperson Jessica Kowal said none of the affected 787s currently in service with airlines around the world “are within a window when they would experience this aging,” and so “this is not an immediate safety of flight issue.”
“We are correcting the issue on airplanes that have not been delivered,” Kowal said. “Analysis is underway to determine if action is required on the in-service fleet.”
As with the aft fuselage quality control problem, the new problem means delivery of 787s, already hit by the falloff in demand from the global pandemic, has been further slowed as Boeing conducts inspections of completed jets.
Though the build 787 rate is still nominally ten jets per month, Boeing delivered just four in April, three in June, two in July and four in August.
In South Carolina, Boeing identified two separate quality defects in fabrication of the aft fuselage, both at the join between the pressurized section that is the rear of the jet’s passenger cabin the unpressurized and tapered barrel section behind it, which is where the jet’s horizontal tail is attached.
One of the South Carolina flaws — pieces of material called shims used to fill gaps in the structure as the two sections are joined were the wrong size — was discovered in August 2019 and corrected on jets built since then.
The second flaw, discovered last month, revealed that the inner surface of the fuselage at the join was insufficiently smooth.
When analysis showed that the combination of the two flaws — wrong-sized shims and a non-flat inner skin surface — could together create unacceptable gaps at that fuselage join, Boeing last month was forced to ground eight 787s in service with various airlines, including United, Air Canada and Singapore Airlines.
Boeing said Tuesday it is now inspecting every complete but undelivered 787 for the two ongoing flaws: unacceptable roughness of the inner skin at the aft fuselage join and gaps larger than specification in the horizontal tail.
Boeing is still consulting with the Federal Aviation Administration (FAA) and working out the implications for jets in service of all three manufacturing flaws.
Over the Labor Day weekend, the FAA said in a statement that it is investigating 787 manufacturing flaws, adding that “it is too early to speculate about the nature or extent of any proposed Airworthiness Directives that might arise.”
At the beginning of the 787 program, Boeing outsourced fabrication and assembly of the jet’s horizontal tail to subcontractor Alenia at a plant in Foggia, Italy. However, major quality issues there caused multiple delays and in 2012 when the second Dreamliner model, the 787-9, was introduced, Boeing opened its own horizontal tail assembly plant in Salt Lake City.
The horizontal tail work was eventually taken away from Alenia altogether so that all the stabilizers are now made in Utah.
More MAX cancellations
Boeing on Tuesday also released its jet orders and deliveries figures for August. The data shows that another another 91 orders for the still-grounded 737 MAX have either been canceled or are considered at this point unlikely to be fulfilled.
That brings the total of 737 MAXs either cancelled outright or removed from the official backlog to 955 aircraft so far this year.
August activity consisted of 17 outright cancellations of the MAX, 13 by major lessors Aercap, Aviation Capital and GECAS, two by Icelandair and three by unidentified buyers.
Boeing also removed an additional 74 MAXs from its official backlog.
Although the order contracts for these aircraft are not formally cancelled and are still under negotiation between Boeing and the buyers, the jetmaker considers the orders unlikely to be fulfilled at this point and so accounting rules require that they no longer be counted in the backlog.