Doomed Ethiopian Airlines Flight 302 was seen “swerving and dipping” as smoke billowed from the massive aircraft just moments before it crashed, a witness said Monday — as officials revealed they’ve recovered the damaged black box and a cockpit voice recorder.

“Before it crashed the plane was swerving and dipping with a lot of smoke coming from the back and also making a very loud unpleasant sound before hitting the ground,” Gebeyehu Fikadu, 25, told CNN.

Flight data suggested the Boeing 737 MAX 8 wildly gained and lost altitude, but Fikadu’s recounting was one of the first eyewitness accounts of the crash. All 157 people aboard, including at least eight Americans who have not yet been publicly identified, were killed.

Another witness, Tamrat Abera, said smoke was pouring out of the back of the plane before it crashed.

“Before falling down, the plane rotated two times in the air and it had some smoke coming from the back, then it hit the ground and exploded,” Abera said. “When the villagers and I arrived at the site, there was nothing except some burning and flesh.”

Ethiopian Airlines tweeted that it recovered the flight data recorder from the wreckage — but did not appear any closer to determining a cause. A cockpit voice recorder was also recovered.

The airline said it decided to ground its fleet of MAX 8s beginning Sunday.

“Although we don’t yet know the cause of the accident, we had to decide to ground the particular fleet as extra safety precaution,” it said.

Flight 302 crashed shortly after taking off from Bole International Airport in Addis Ababa, Ethiopia, just after 8:30 a.m. local time Sunday. It was headed for Nairobi, Kenya, in what is usually a routine two-hour jaunt.

The crash was the second in five months involving a MAX 8 — a single-aisle model that was introduced in 1967.

The only two US airlines that fly MAX 8s are American Airlines, which has a fleet of 24, and Southwest, which has 34, according to their spokesmen.

Neither have plans on grounding their fleet.

“We will closely monitor the investigation via Boeing and the NTSB. Any changes at this time may have an added cost,” American said on Twitter.

Southwest said, “We remain confident in the safety and airworthiness of our entire fleet of more than 750 Boeing 737 aircraft, and we don’t have any changes planned to 737 MAX operations.”

United Airlines flies 14 MAX 9s. Both the MAX 8 and 9 utilize the same navigation system, aviation expert Ross Aimer told The Post.

A glitchy navigation system is suspected in the other fatal MAX 8 crash, in Indonesia, which killed all 189 aboard the Lion Air flight last October.

Boeing stocks took a nosedive Monday. Company shares fell more than 5 percent, closing at $400.01.

With Wires