Over time, users may encounter pre-arm errors that will prevent takeoff. Usually the user will take note of pre-arm errors in the bottom center of the screen, displayed with a yellow dialog box. The user can also view a log of errors via the megaphone icon on the icon bar at the top of the screen. The icon has two states: no alerts and unread alerts. If there are no alerts it will be displayed as a megaphone icon, and unread alerts will display as a triangular warning icon.
...
Below, a list of pre-arm errors that the user may encounter during general operations has been compiled, along with actions the user can take to resolve them.
...