NEWARK, NJ. — An investigation is underway after sparks and debris were spotted streaming out of a United Airlines flight.

>>> STREAM CHANNEL 9 EYEWITNESS NEWS LIVE <<<

A frightening video shows the incident that happened Wednesday night, shortly after the airliner took off.

Flight number 149 took off from Newark, New Jersey and was headed to Brazil.

Watch: Video shows passenger attacking American Airlines flight attendant

The sparks and debris from the aircraft fell onto parked cars below.

The pilot circled over the Atlantic Ocean for nearly two hours to burn off fuel and lighten the plane, before returning to Newark.

Watch: Battle lines forming over Orange County transportation tax vote

“Precautionary methodology would be to say, ‘if we’ve got sparks coming off the back maybe we better not dump fuel,’ flying around a little bit to burn the fuel off is the best methodology,” said aviation analyst John Nance.

The plane was carrying 256 passengers and landed safely.

Watch: Hurricane Fiona to bring rough surf, strong rip currents to Volusia County beaches

United Airlines said the jet experienced a mechanical issue with its hydraulics system.

Click here to download the free WFTV news and weather apps, click here to download the WFTV Now app for your smart TV and click here to stream Channel 9 Eyewitness News live.