The Chilean Hercules C-130 plane that crashed on its way to Antarctica this week killing all 38 people on board suffered an emergency three years ago on the same route, the air force said on Saturday.
Following the plane's disappearance after taking off from the southern city of Punta Arenas, local media broadcast a video showing emergency equipment including firefighters and ambulances waiting on the runway in the city's airport in April 2016.
In a statement, the Chilean Air Force said the plane shown in the footage is the same one that crashed as it was crossing the Drake Passage connecting the Atlantic and Pacific en route to a Chilean airbase.
As it came to land at the base in Antarctica in 2016 "the crew realized that the left main gear of the aircraft did not travel to the down position and secure when activating the landing gear," the statement said.
The pilot decided to turn back to Punta Arenas, using an alternate method to lower the landing gear and touching down uneventfully, the statement added.
The air force has previously said the crashed plane's maintenance record was in order, but that it would investigate a WhatsApp audio message sent by a passenger to relatives that allegedly said the plane was having electrical problems.
Authorities say they have not ruled out anything as to the cause of the crash, which killed all 21 passengers and 17 crew aboard.
Debris from the plane was located in a 12 square mile (30 square kilometer) area in the Drake Passage, a storm-tossed body of water south of Cape Horn.
On Friday, remains of people killed in the crash were turned over to a coroner for identification.