Australian authorities tight-lipped on Qantas pilot death

Paul Whyte, a first officer on the Australian airline's international flights, was the only person aboard a rented Cessna 172 when it vanished from radar late Monday over the Pacific Ocean 11 kilometers (seven miles) northeast of Byron Bay, near Australia's most easterly point, Northern Rivers Aero Club president Wally Soward said.

Pilot suicide is also a theory behind the mysterious disappearance of Malaysia Airlines Flight 370 after it flew far off course during a flight from Kuala Lumpur, Malaysia, to Beijing on March 8, 2014.

Since the Germanwings disaster, Qantas joined with many international airlines in ensuring that at least two crew members remain in cockpits if a pilot leaves for any reason.