Tegan Jovanka
Tegan first appears in the Fourth Doctor's last serial, Logopolis. On her way to Heathrow Airport to start her new job with Air Australia, her car suffers a flat tyre. She enters a roadside police box to seek help, but she enters and does not realise that it is the Doctor's Tardis. She is present when the Fourth Doctor falls from the Pharos Project radio telescope and regenerates into his fifth incarnation, and continues to travel with the doctor