Scarce quality data on 787 skins as FAA peels back onion on Boeing

On the evening of August 24, an 18-month old United Airlines Boeing 787-10 touched down at Newark Airport after a 7-hour and 39-minute journey from Frankfurt. It was to be the young jet’s last flight for a while. 

The aircraft was yanked from service the following day, after Boeing engineers concluded an analysis of manufacturing data that indicated a key structure in the rear of the aircraft’s fuselage was compromised by two separate manufacturing issues. The analysis determined the jet would be unable to withstand the required maximum expected stresses of normal operation.

The circumstances that led up to the abrupt grounding of the N16008, United’s jet, and seven other 787s around the world at airlines like Singapore Airlines and Air Canada are becoming clear. The new facts — gathered since The Air Current’s first reporting on the grounding on Aug. 27 according to several people briefed on the situation — still leave significant questions unanswered for the 787 fleet and the manufacturing system that builds Dreamliners.

Related: Boeing yanks eight 787s from service over structural issue

On Monday, following a report by The Wall Street Journal, the FAA confirmed it had opened an official investigation into the manufacturing flaws on the 787. The U.S. aviation regulator said that it “continues to engage with Boeing. It is too early to speculate about the nature or extent of any proposed Airworthiness Directives that might arise from the agency’s investigation.”

Principally, the reason it is too early to speculate, in the words of the FAA, is because those eight airplanes have not yet been inspected, and the extent of the manufacturing issues will not be fully understood and how they may impact the rest of the fleet, according to interviews with several familiar with the concerns.

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A Boeing spokeswoman said that the company “continues to assess the in-service fleet” and based on its assessment it may need to conduct additional rework, inspections or no action at all.

The eight grounded airplanes, all built in 2019, though not sequentially, have been cleared for a ferry flight as Boeing conduct its Airplane On Ground (AOG) operations at three sites, Newark, N.J., Abu Dhabi and Victorville, Calif. according to two people familiar with the company’s plans. A Boeing spokeswoman said “it continues to work closely with our customers and to facilitate repair of all eight airplanes.”

Airplanes from Etihad Airways, Air Europa, Norwegian Air Shuttle and All Nippon Airways are also impacted by the grounding, according to one of the people familiar with the affected fleet. One airline has two grounded 787s. The four additional airlines were first reported by WSJ on Monday.

Why inspections may eventually cover nearly the entire 787 fleet is now clear to TAC, and more importantly opens a fresh can of worms around Boeing’s quality processes at its North Charleston, S.C. plant fabricates the jet’s carbon fiber aft fuselage sections that have frequently been examined by the FAA.

Related: Boeing’s long and inevitable road to South Carolina

The latest investigation comes at a time where the relationship between Boeing and the FAA has been badly damaged by the 737 Max crashes and the single-aisle jet’s subsequent grounding. Boeing is already on a short leash with the Max, and that seems likely to spill over to the 787 and any additional findings the FAA may uncover. All of this comes amid a market for long-range airplanes where airlines and lessors are seeking any reason to get out of taking delivery of new jets.

Boeing is confident the population is limited to the eight affected aircraft with the combination of both the shimming and skin surface smoothness problems in the jet’s aft fuselage, first reported by TAC.

The two issues together undermine the structural integrity of the 787’s aft fuselage join, making it unable to withstand the limit load or maximum forces the airplane could experience in service, according to a Boeing engineering analysis. 

Officially, both issues in combination are unlikely to crop up on the rest of the fleet. The company said an additional small number of in-service 2019 aircraft, which it declined to disclose, has the shim issue, which it first found in August 2019. The Boeing spokeswoman could not say if any undelivered 787s were reworked because of the shim issues, but said any aircraft “would’ve been corrected before delivery.” 

Separately, Boeing said, the issues do not compromise the strength of the structure to a point where it does not meet the limit load requirement.

On Tuesday, in a short statement, Boeing also acknowledged an additional quality issue on the 787 related to the jet’s horizontal stabilizer. The company has slowed deliveries of 787s to undertake inspections on the stabilizer and the skin smoothness issue inside the aircraft’s aft fuselage.

A Boeing spokeswoman said that a regular audit of its production system last month uncovered the skin smoothness issue and “because of the location of both” manufacturing issues in the aft fuselage Boeing “went back to look at the early 2019 batch of airplanes” with the shim issue and decided to recommend pulling the eight 787s from service immediately.

Crucially, Boeing has extensive manufacturing data on the shims, but little on the quality of the composite skin surface issue, which is now driving the FAA toward recommending an examination of potentially the entire 787 fleet, which numbers nearly 1,000 since the first delivery in 2011. Only its findings on the eight grounded airplanes will determine what comes next.

“Best case the surface quality on these eight airplanes is good and then Boeing can put together a defendable argument that taking the things apart [across the fleet] isn’t needed,” said one of the people familiar with the issue. “Worst case these eight have poor surface quality and then the above argument is very difficult to make.”

Quality system under scrutiny

While the spotlight is on the eight grounded jets, the concern, however, is more about each issue separately and its reflection on Boeing’s Quality Manufacturing System (QMS). Principally that the QMS didn’t catch the errors as the company has sought to justify reduced inspections in areas of the assembly process that have a history of “accuracy and stability,” according to the people familiar with the issues.

In the case of the aft fuselage join now under scrutiny by the FAA, the quality issues have revealed that the process was neither accurate nor stable with both the shim and skin surface issues cropping up.

In the five months between the 737 Max crashes of Lion Air 610 and Ethiopian 302, Boeing made the case to publications like The Seattle Times that it was ready to cut back 450 quality inspector positions in 2019 and another 450 in 2020 because of high tech tools it believed it had fielded successfully to create “proven processes” that only needed occasional and infrequent checks.

The process of using more automated and time-saving technologies to develop shims for the 787’s structure was one at the center of its argument that it didn’t require as much oversight from quality assurance staff. Boeing specifically cited a new tool designed to speed up shimming on the 787. The eight grounded 787s were manufactured by Boeing in 2019.

Those familiar with the FAA investigation into the 787’s quality concerns say that the assembly of the Section 47/48 and aft pressure bulkhead at the company’s North Charleston, S.C. facility has been considered to be one of those stable processes that the company can complete consistently.

Write to Jon Ostrower at jon@theaircurrent.com