It was only after a second MAX accident in Ethiopia nearly five months later, these officials said, that Boeing became more forthcoming with airlines about the problem. And the company didn’t publicly disclose the software error behind the problem for another six weeks, in the interim leaving the flying public and, according to a Federal Aviation Administration spokesman, the agency’s acting chief unaware.

The length of time between when Boeing realized the problem and when it shared that information hasn’t been previously reported. The problem kept a safety feature found on earlier models from functioning on the MAX, though it isn’t clear if the feature would have prevented either crash.

Senior FAA and airline officials increasingly are raising questions about how transparent the Chicago aerospace giant has been regarding problems with the cockpit warnings, according to people familiar with their thinking.