JetBlue Flight 1230 was flying from Cancun, Mexico, to Newark, New Jersey, on Thursday.
Around 1:48 p.m., the Airbus A320 fell about 30 meters in only seven seconds.
The pilots asked for an emergency landing and turned the plane toward Tampa International Airport.
Medical teams were waiting at the airport.
Fifteen people, including two children, had minor injuries and went to the hospital.
All of them were released the same day.
The pilots told air traffic control that the plane had a flight control issue.
The Federal Aviation Administration is looking into the problem.
The National Transportation Safety Board is also watching the case but has not opened its own investigation yet.
A cold front had just passed over Florida, bringing wind and light rain, but experts do not know if the weather caused the drop.
JetBlue has taken the plane out of service for a full inspection.
The airline said that the safety of customers and crew is its first priority.