A KEY clue that was found six miles from where the Boeing 737 crashed could unlock the mystery of the doomed flight.

       It comes after a black box that was found near the disaster site in Guangxi, China, was "severely damaged" and it's not known whether investigators would be able to retrieve any data.

       5

       The passenger jet was seen plunging at 700mph 5

       Rescue teams have been scouring the area near the city of Wuzhou Credit: Getty 5

       Investigators have found hundreds of pieces of debris Credit: Alamy

       Shocking footage showed the China Eastern Airlines passenger jet crashing into a mountain at 350mph near the city of Wuzhou on Monday.

       The jet was heading to Guangzhou from Kunming and was carrying nine crew members and 123 passengers.

       According to FlightRadar24 data it plunged 29,100ft in around minute and a half.

       And while investigators are still searching for the second black box in the debris another piece of evidence might be able to shed some light to the flight's final moments.

       READ MORE ON CHINA

       FLYING DRAGON Supersonic jet could bring passengers from New York to China in an HOUR

       RED ALERT UK 'will slap China with hard-hitting sanctions if it supports Russian invasion'

       Only six miles from the site a farmer has found a long metal strip, suspected to be a piece of the aircraft, reports South China Morning Post.

       Huang Jianyi, 80, said he found the piece of metal while working in a paddy field in the village of Siwang on Tusday after the crash.

       “I saw a piece of metal. It was white,” he said.

       The finding indicates that there might have been some kind of mid-air malfunction that led to the deadly crash.

       Most read in The Sun

       TAXING TIMES Council tax rebate worth ￡150 to start hitting bank accounts within DAYS

       SCUMBAG Brother of thug who kidnapped Angel Lynn & left her brain-damaged mocks her online

       'yes it's a fix!' DOI star Brendan Cole stuns Holly and Phil by saying the show IS fixed

       'IT'S A SHOCK' This Morning in Covid shock as Vanessa Feltz tests positive after filming

       Jeff Guzzetti, the former chief of accident investigations at the US Federal Aviation Administration said: “The questions are: exactly what piece was it and when did it come off?”

       While it's currently not known the reason the piece of the plane broke Guzzetti said it most likely happened as the plane plummeted to the ground.

       “In my view, that’s the aircraft shedding parts as it’s coming down,” he added.

       The piece of debris also suggests the investigators must expand the area of search as they're looking for answers.

       Zheng Xi, head of the Guangxi regional fire and rescue office, said the piece of suspected wreckage was about 4.3ft.

       He added that the search team have expanded the area they cover by half.

       Investigators have so far have searched over 14 acres and recovered 1,800 pieces of debris, state broadcaster CCTV reported.

       The China Eastern flight departed at 1:11 pm (0511 GMT), FlightRadar24 data showed and had been due to land at 3:05 p.m. (0705 GMT).

       Flight-tracking says the descent started between 06:20:43 and 06:20:59 from an altitude of 30,000 feet.

       The plane is understood to have then dropped to just 7400 feet in a matter of minutes before pulling up - climbing 1,200 feet.

       It then nosedived and smashed into the ground.

       Read More on The Sun

       SICK THREAT 'Butcher of Mariupol' asks why soldier hasn’t been MUTILATED for wrong uniform

       ROYAL RIBBING My pal Prince Harry BLACKLISTED me over very cheeky joke, says Jack Whitehall

       Experts are baffled by the crash - and investigators said it is too early to speculate on the cause.

       An air-traffic controller tried to contact the pilots several times after seeing the planes altitude drop sharply, but didn't get any reply, Zhu Tao, director of the Office of Aviation Safety at the Civil Aviation Authority of China, said.

       5

       Debris was seen scattered on the ground Credit: AFP 5

       The crash sparked a fire on the mountain on Monday We pay for your stories!

       Do you have a story for The Sun news desk?

       Email us at exclusive@the-sun.co.uk or call 0207 782 4104. You can WhatsApp us on 07423 720 250. We pay for videos too. Click here to upload yours

       Click here to get The Sun newspaper delivered for FREE for the next six weeks.