Boeing allegedly took shortcuts to ease production bottlenecks for its 787 Dreamliner aircraft that could eventually impair the structural integrity of more than 1,000 of the widebody jets in service, according to a quality engineer who worked on the planes.

The embattled plane-maker wrongly measured and filled gaps that can occur when airframe segments are joined together, according to Sam Salehpour, a long-time Boeing employee who made his concerns public on Tuesday.

Over time, the issue could lead to "significant fatigue,” according to a Jan. 19 letter to U.S. aviation safety regulators by the law firm Katz Banks Kumin in Washington, which is representing Salehpour as a whistleblower.