Boeing 787 Dreamliner mishap brings safety concerns back front and center.

It's one of the company's most crucial aircraft, but the 787 has been plagued with design and production delays and now, test flights are revealing new problems - and raising new questions.

Some engine parts fell off during a ground test at the Charleston, S.C. airport over the weekend, forcing officials to close the airport for more than an hour.

The Dreamliner is supposed to be the leading edge of commercial aviation - one of the most advanced jetliners ever built. But the mishap during Saturday's test once again has raised concerns.

"This is extremely unusual to have parts coming off an engine, particularly a brand new engine," observes CBS News aviation and transportation safety analyst Mark Rosenker.

No one was hurt, but some flights were diverted after the metal debris sparked a grass fire at the airport.

And because the engine is already used on other commercial aircraft, the National Transportation Safety Board wants to know what went wrong.

"Clearly, if there are issues of design or materials, they'll understand that a lot better when they begin to tear that engine down piece by piece," Rosenker notes.

Analysts say the 787 is the future of the industry. And with more than 800 aircraft still on order, costing about $200 million each, the Dreamliner is enormously important to Boeing's bottom line.

In a statement, the company said, "While the investigation is in its early stages, we are unaware of any operational issue that would present concerns about the continued safe operation of in-service 787s powered by GE engines."

But earlier this month, the Japanese airline ANA grounded its Dreamliners when problems were found with those planes' engines, which are manufactured by Rolls Royce.

And in February, Boeing ordered inspections of all 787s after defects in the fuselage were discovered.

In fact, a myriad of production problems delayed delivery of the first Dreamliner by three years.

Still, Rosenker, a former chair of the NTSB, says the testing process is supposed to reveal problems like these, so the flying public shouldn't be too worried.

"Despite all the problems that may have been reported over the past year, this aircraft is an extremely efficient, extremely safe aircraft," he says.