Problem 1: Which weather phenomenon signals the beginning of the mature stage of a thunderstorm?
Problem 2: What feature is normally associated with the cumulus stage of a thunderstorm?
Problem 3: What visible signs indicate extreme turbulence in thunderstorms?
Problem 4: Each required flight crewmember is required to keep his or her shoulder harness fastened.
Problem 5: Required flight crewmembers' seatbelts must be fastened.