Boeing CEO David Calhoun on Tuesday said the aviation giant had erred leading up to the Alaska Airlines incident last week, promising that company leadership is working with regulators to ensure the terrifying mid-air panel blowout won’t be repeated. Speaking at a staff-wide safety meeting, Calhoun said, “We are gonna approach this—number one—acknowledging our mistake,” according to audio of the meeting reviewed by The Wall Street Journal. “We’re going to approach it with 100 percent and complete transparency every step of the way. We are going to work with the [National Transportation Safety Board], who is investigating the accident itself, to find out what the cause is.” It was unclear whether Calhoun elaborated on the exact nature of the mistake in the meeting, but a company source told CNN that Boeing believes “the mistake in question” was introduced in the plane’s manufacturing supply chain. Calhoun admitted that the incident, in which one of the aircraft’s door plugs detached at 16,000 feet, had left airlines spooked. “Moments like this shake them to the bone, just like it shook me,” he said. “They have confidence in all of us—they do—and they will again.”