A Boeing quality engineer called on the company to ground its "entire fleet" of model 787 airliners during an interview Tuesday, one day before he's set to testify before Congress about his concerns they could come apart mid-flight.

"I would say they need to," Sam Salehpour told NBC News after being asked if Boeing should ground the planes. "The entire fleet, worldwide."

Salehpour previously told the New York Times for a report last week that sections of the 787's fuselage were improperly assembled, with gaps that don't meet company specifications.

He said the situation could cause the plane, known as the Dreamliner, to break apart midflight after thousands of trips.

Salehpour also shared his allegations about the 787 with the Federal Aviation Administration, which told the Times it was investigating.

In the NBC interview, Salehpour said, "The entire fleet worldwide, as far as I'm concerned, right now needs attention."

"And the attention is, you need to check your gaps, make sure that you don't have potential for premature failure."

Salehpour went public with his allegations about the 787 following a January 5 incident in which a door panel blew off a Boeing 737 Max 9 midflight, prompting a corporate shakeup and a criminal probe by the Justice Department.

Salehpour is scheduled to appear Wednesday before the Senate Permanent Subcommittee on Investigations, which has asked outgoing Boeing CEO David Calhoun to also testify.

Boeing has called Salehpour's allegations "inaccurate" and said they don't "represent the comprehensive work Boeing has done to ensure the quality and long-term safety of the aircraft."

On Monday, the company also held a briefing for reporters at the factory in North Charleston, South Carolina, where the 787 is assembled.

Boeing engineers said the plane, built with large amounts of lightweight composite materials instead of metal, has undergone extensive testing that showed the gaps met specifications in about 99% of all cases, according to the Times.

The engineers also said the plane's structural integrity wouldn't be compromised even if the gaps exceeded specifications by a reasonable amount.