The U.S. National Transportation Safety Board said on Monday it is investigating a United Airlines flight on Friday from Lagos, Nigeria to Washington D.C., in which a sudden aircraft movement led to injuries of passengers and cabin crew.

Nearly 40 people were injured, with six seriously injured, when a Boeing aircraft operated by United Airlines suddenly plunged in mid-air, forcing the fight to make an emergency landing.

A United Airlines flight from Africa to Washington D.C. had to turn around on Thursday after a "technical issue" caused "unexpected aircraft movement," the airline said.

New video shows frightening moments onboard a United Airlines flight bound for Washington, D.C., after what officials are calling a “technical issue” occurred.

The plane experienced an “unexpected aircraft movement” during flight, and aviation authorities in the United States and Nigeria are investigating the cause, the spokesperson said. Four passengers and two crew members aboard flight 613 were seriously injured,

Image via Shutterstock It was a chaotic scene after a United Airlines flight touched down in Africa. The Boeing plane had to make an emergency landing at the airport. This comes after the flight suddenly plunged downward in mid-air.

Nearly 40 people were injured, with six seriously injured, when a Boeing aircraft operated by United Airlines suddenly plunged in mid-air, forcing the fight to make an emergency landing. According to CNN,