The accident puts more scrutiny on Boeing and its CEO. The company has struggled with a string of defects on its planes over the past few years, while it tried to ramp up production and improve its reputation after fatal crashes in 2018 and 2019.
The company is also awaiting certification of its smaller Max 7 and largest Max 10 models. Calhoun told CNBC on Wednesday the Max 9 grounding shouldn't affect those approvals.
"This issue is on a discrete set of airplane," he said. "They're very much unrelated."
The FAA grounding does not affect the more common 737 Max 8, which is also in commercial use.
Calhoun said Tuesday that the company will work with the National Transportation Safety Board in its investigation and that the FAA is overseeing inspections "to ensure every next airplane that moves into the sky is in fact safe and that this event can never happen again."
— CNBC's Sara Salinas contributed to this report.
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