Salehpour also raised flags about the 777, saying in his complaint that a redesign of the jet's assembly process to speed up production used "unmeasured and unlimited" force to get the fuselage to fit together.

Boeing has backed its widebodies despite the whistleblower complaint, telling BI in an email statement on Tuesday that Salehpour's allegations are not representative of the work it has done to "ensure the quality and long-term safety of the aircraft."

Boeing said the 787 can fly for more than 30 years before it needs heavy maintenance to extend its life and that it is fully confident in the safety of its in-production and in-service Dreamliners.

The Boeing 787 is the company's best-selling widebody jetliner and is favorable for its different variants that come in three sizes — small, medium, and large — all with varying ranges and capacities.

The allegations will also likely not help Boeing escape heightened scrutiny about its quality control after a door plug on an Alaska Airlines 737 Max 9 fell off mid-flight.

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