That's after a panel tore off a 737 MAX 9 in midair.
The Alaska Airlines flight landed without major injuries, but the drama has revived concern over Boeing's top-selling plane.
On Tuesday, the firm named retired admiral Kirkland Donald as its new quality adviser.
He will lead a team of outside experts in evaluating quality controls at the firm.
Some analysts welcomed the news.
But aviation consultant Richard Aboulafia told Reuters it was odd to choose an adviser with no background in the industry.
The news certainly wasn't enough to save Boeing shares, which sank another 8% or so on Tuesday.
They are now down more than a fifth since the start of the year.
The U.S. Federal Aviation Administration has grounded 171 MAX jets until further notice.
Besides Alaska, the affected variant is also operated by United Airlines.
Boeing has already set out other steps, including allowing airlines to conduct their own checks on the production process.
But the incident has ramped up calls for management changes.
Ryanair boss Michael O'Leary - one of Boeing's biggest customers - said the firm needed someone "cracking heads, ensuring quality".
