“Michaelis asked if any alert would tell them when the sensors had failed. “On your airplane, yes,” Sinnett answered. Without mentioning that Boeing had botched the software implementation on other planes, he explained that American had purchased the optional angle-of-attack indicator, which Lion Air had not. Had it been Michaelis’s plane, a little flag notice would have popped up alerting him to disagreement between the AoA vanes, and mechanics would have fixed the sensor on the ground. “So you would not have taken the airplane,” he said.”