NORTH CHARLESTON, South Carolina — At its 787 Dreamliner manufacturing complex in South Carolina on Monday, Boeing detailed an immense amount of analysis and testing it has done since the discovery in 2020 of small gaps at the fuselage joins on the jet.
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 importantly, Boeing insists that extensive testing overseen by the Federal Aviation Administration and inspections of the current in-service fleet shows 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 press briefing and tour of the 787 fabrication and final assembly facility in North Charleston, S.C., Boeing scrambled to respond to damaging allegations last week 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 this 40,000 times. It 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 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 or deteriorate.
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 and 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 from 2010 was cycled through the loads and pressurization of 165,000 simulated flights — three-and-a-half 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 on a press conference call 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.
On Wednesday, Salehpour is due to speak at a U.S. Senate hearing. Boeing did what it could Monday to contradict his account.
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