The investigation into a Jeju Air crash in South Korea has found both engines on the plane sustained bird strikes but the pilots turned off a less-damaged one just before its crash-landing.

The South Korea-led investigation into Jeju Air's fatal plane crash in December has "clear evidence" that pilots shut off the less-damaged engine after a bird strike, a source with knowledge of the probe said on Monday.

South Korean investigators have uncovered substantial evidence indicating that pilots of the Jeju Air flight that crashed in December mistakenly shut down the less-damaged engine following a bird strike,