NORTH CHARLESTON, S.C. — At its 787 Dreamliner manufacturing complex on Monday, Boeing responded to damaging new whistleblower allegations by detailing the results of testing it has done since small gaps between fuselage pieces on the jets were discovered four years ago.
Boeing has made meticulous, time-consuming changes to the way it manufactures the 787’s carbon composite airframe to eliminate the gaps. It must do so to meet the specification.
More important, Boeing insists that extensive testing overseen by the Federal Aviation Administration and inspections of the current 787 fleet show definitively that the gaps, which exist in nearly 1,000 Dreamliners flying today, pose zero safety risk.
“We haven’t identified any safety issues,” said Steve Chisholm, chief engineer for Boeing Mechanical and Structural Engineering. “We have not seen anything in service related to [the gaps] that would indicate that there is an issue with the in-service fleet.”
In a news briefing and tour of the 787 fabrication and final assembly facility in North Charleston, S.C., Boeing scrambled to respond to the allegations by Sam Salehpour — an Everett engineer who worked on the 787 and 777 programs, now a public whistleblower — that it has not eliminated the gaps and that they pose a risk of “catastrophic failure.”
Salehpour’s allegations come as Boeing continues to face fallout from a Jan. 5 midair blowout that saw a panel pop out of a 737 MAX 9. That incident prompted ongoing inquiries into the 737 program and raised fresh questions about Boeing’s broader safety culture.
In response to Salehpour’s claims, Boeing described its testing and manufacturing changes to journalists during a visit to its North Charleston facility.
Engineers smashed 300-pound spheres swinging on a pendulum into a fuselage section to deliberately damage it, causing one of the stiffening rods to break. They then applied loads 15% greater than those typical in flight and repeated the load tests 40,000 times. Boeing found “there was no growth in the damage,” Chisholm said.
He contrasted this with what happens on a metal airframe, such as the 737 or the 747. If a crack develops in the thin metal skin, it can propagate and tear through the structure as if it were unzipping.
While metal fatigue might result in such cracks, Chisholm said fatigue damage to a composite material would take the form of delamination, when the plies of carbon fiber separate.
But no delamination was observed. The localized damage Boeing deliberately inflicted did not spread.
The engineers also cut through a pressurized fuselage with a guillotine blade, slicing a 4-foot section and severing one of the circumferential frames.
The fuselage didn’t even lose pressure, and testing showed the tear did not propagate. The fuselage was able to maintain its structural integrity well above the loads expected in normal operation.
Boeing said the gaps were present in the first Dreamliners ever built, including the ground-test airplane that over five years starting in 2010 was cycled through the loads and pressurization of 165,000 simulated flights — 3½ lifetimes — without showing any structural damage.
Salehpour, the whistleblower, claimed last week that Boeing’s own data from detailed inspections of 26 airplanes showed nearly 99% had gaps larger than the specification of 5 thousandths of an inch, about the thickness of two sheets of paper, and the small filler pieces of glass fiber material used to fill such gaps — known as shims — were not inserted.
At two of the main circumferential joins on those 26 airplanes, “98.7% of the time, the gaps exceeding 5 thou are not shimmed,” Salehpour said at a virtual news conference last week with his lawyers. “Nearly 8,000 gaps exceeding 5 thou were not shimmed.”
Chisholm said the result was “exactly opposite.”
He said Boeing removed every fastener on each of the five circumferential joins on all of those airplanes, about 2,000 fasteners for each join, and measured the gap at each hole — a so-called through-hole inspection.
“Close to 99% were fully conforming and met the 0.005 inch requirement,” Chisholm said.
Boeing also addressed a second claim by Salehpour: that Boeing’s use of a technique to join the airplane sections called “One Up Assembly” left drilling debris in the gaps.
Historically, Boeing would mate two sections together and drill holes, then separate them to clean the holes and smooth out any metal edges on the holes, and only then put the sections back together and insert fasteners.
Most Read Business Stories
One Up Assembly, used for some 787 joins, means drilling and fastening the sections together precisely in a single pass, without separating them to clean the drilled holes.
Salehpour said drilling debris was found “80% of the time” on those 26 airplanes Boeing studied in detail.
But Chisholm said the technique is used only when it can be demonstrated that it doesn’t cause debris in the gaps. Furthermore, he said Boeing did tests deliberately inserting both composite and metal drilling debris into the gaps at the interface to assess the impact.
Sponsored
Those tests “show that it’s not detrimental,” Chisholm said.
On a tour of the building where the two aft fuselage sections are fabricated and joined, Lisa Fahl, Boeing’s vice president of airplane programs engineering, described the steps Boeing has taken to eliminate any gaps above the 5 thousandths of an inch specification, adding considerable work and delay to the assembly process.
New laser measuring devices are used to detect surface unevenness at the edges of the fuselage sections where they are joined, which can result in gaps.
And since 2020, as part of what it calls the “Join Verification Process,” Boeing has inserted a time-consuming extra step at certain difficult joins.
In the normal process, after pulling the sections together, temporary fasteners are inserted and the gaps are measured. After any necessary shims are inserted, permanent fasteners are then tightened.
Since 2020, there’s now an extra step for certain joins with complex contours such as the join of the two aft body sections: a “through-hole” inspection. Each of the 2,000 fasteners at each join is removed by hand and a small tool is inserted to measure the gap. When it is within specification, a new permanent fastener is inserted.
All the 787s previously built and still parked now have to go through this process before they can be cleared for delivery.
A Boeing engineer on the tour said the hope is that as control of the gaps is tightened in the build process for new 787s, this extra check can eventually be dropped.
Chisholm said Boeing is heartened by the data from the 787s in service.
He said 671 have completed their heavy maintenance check required after flying for six years. Another eight have completed their 12-year check.
Boeing sent teams of engineers to take a close look at 10 of those maintenance inspections.
“Through all of this, there’s been zero airframe fatigue findings on the 787 fleet,” Chisholm said.
Boeing said it is up to the FAA, once it has all the data from Boeing’s tests and from the in-service fleet, to decide if anything needs to be done about the fuselage gaps on the 787s flying today.
“It’s a long, very deliberate process,” Chisholm said. “We do expect to complete it this year.”
In addition to discussing the 787 in detail, Boeing also responded to Salehpour’s critique of a new 777 build process that was introduced in 2015.
Salehpour said the 777’s metal fuselage panels that are fastened together into fuselage sections in Everett don’t come together easily and that machinists sometimes jump on the panels to force them into position.
“That’s not part of our process,” said Boeing’s Fahl.
And Chisholm said: “I would expect any employees who are seeing other employees jumping up and down on panels to let us know.”
He added that 27 airplanes built in the new process have completed their eight-year heavy maintenance checks with no issues found.
On Wednesday, Salehpour is due to speak at a U.S. Senate hearing.
After the Boeing briefings finished, his lawyer, Debra Katz, issued a statement saying that Salehpour had tried for years inside Boeing to see data that would allay his concerns but was rebuffed and managers retaliated against him for raising the issue.
“Boeing has always said ‘just trust us,’ when it comes to safety,” Katz wrote. “It’s clear that standard is no longer sufficient, and any data provided by Boeing should be validated by independent experts and the FAA before it is taken at face value.”
Dominic Gates: 206-464-2963 or [email protected]; Dominic Gates is a Pulitzer Prize-winning aerospace journalist for The Seattle Times.