Passengers were left in fear for their lives when a pilot encountered landing difficulties while operating a Frontier Airlines flight bound for Puerto Rico. Frontier Flight 5306 from Orlando was carrying 228 passengers and approaching Luis Marín Muñoz International Airport in San Juan on Monday when its landing was aborted at the last second. The Airbus A321 encountered a 'mechanical problem' when one of the wheels broke off the front landing gear, the airline told El Nuevo Día newspaper. FlightAware - the flight tracking company - showed that aircraft flew around the airport four times and made a second landing...