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.

A United Airlines flight bound for Puerto Rico made an emergency landing at Newark Liberty International Airport on Saturday morning, according to the FAA. The flight returned to Newark around 10 a.m.

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

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,

A United Airlines flight from Nigeria was forced to make an emergency landing after six people were injured following an unexpected mid-air jolt.

A United Airlines flight to Washington, DC, was forced to make an emergency landing after the Boeing plane abruptly plunged in midair, hurting nearly 40 people onboard, including six hospitalized with serious injuries,