Don Coryell, the architect of one of the greatest passing offenses in NFL history, passed away on Thursday afternoon. His cause of death is unknown.

Best known for his run with the San Diego Chargers as head coach, Coryell was guiding force behind “Air Coryell,” the offensive supernova that helped redefine the passing game.

During his run as Chargers head coach, San Diego amassed a record of 69-56. Combined with his totals as head coach of the St. Louis Cardinals, Coryell’s record finished at 111-83-1.

He led his teams to six playoff appearances but never reached the Super Bowl. His Chargers made it to the AFC Championship game in ’80 and ’81 but came up short against Oakland and Cincinnati respectively.

Coryell’s true calling card became his work in San Diego with Hall of Fame quarterback Dan Fouts and his vast array of offensive weaponry. Over the course of four straight seasons, the Chargers finished tops in offense; while San Diego’s tremendous passing attack ranked first in six straight seasons from 1978-85.