Dwight Yoakam -- Pilot's Mayday Call ... OUR PLANE'S ON FIRE!!!

Dwight Yoakam's plane was on fire ... IN THE AIR! That mayday call from the pilot triggered an emergency at Van Nuys Airport, where the runway was cleared and the fire department nervously waited.

Yoakam and 9 others were on board the twin-engine Hawker 800 jet over the weekend ... when the pilot called the tower to report an engine fire.

The plane landed safely ... turns out there was a lot of smoke but no fire.

Yoakam was on his way home after playing a small, private gig in a tiny village in Canada's Northwest Territories -- about 1,300 miles due North of Great Falls, MT.

The event was a 50th birthday party ... thrown by a woman who had more than enough to pay the country singer ... because she just won a $7.6 million dollar lottery jackpot.