MELBOURNE, Australia — A commercial pilot is under investigation after falling asleep in the cockpit of a freight plane and overflying his Australian island destination by 29 miles, officials said Tuesday.

The pilot, who has not been identified, was the only person aboard the twin-propeller Piper PA-31 Navajo Chieftain and was flying on autopilot during the early morning flight on Nov. 8 from Devonport city on Tasmania 155 miles northwest to King Island in Bass Strait, his employer, Vortex Air, said in a statement.

The pilot "unintentionally fell asleep while in command of the aircraft," the Melbourne-based airline said.

"The issue became apparent when air traffic control was unable to contact the pilot in-flight, and the aircraft traveled past the intended destination point while operating on autopilot," the statement said.

Air traffic control recordings showed several radio calls were made to the unresponsive pilot, The Australian newspaper reported.

The pilot landed safely on King Island, Vortex Air said.

The Australian Transport Safety Bureau, a crash and risk investigator, and the Civil Aviation Safety Authority, the aviation industry regulator, are investigating the incident and the company's management of pilot fatigue.

The bureau confirmed that the plane had overflown the King Island Airport by 29 miles due to the pilot sleeping. It said it would interview the pilot and review Vortex Air's operational procedures before a report on the incident is made public.

Vortex Air said the 6:20 a.m. flight had been the first on the pilot's first day back at work after taking leave. He continued flying that day.

The newspaper said the pilot reported for duty despite having had little or no sleep the previous night due to a personal crisis.

"Vortex Air takes the safety of our passengers, crew and pilots extremely seriously and always abide by all safety procedures," the airline said.

"This is an extremely rare occurrence, as demonstrated by the company's excellent safety track record," it added.

The company said it was assisting the pilot to "safely return to full duties."