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 when a Boeing 787-800 plane suddenly lost altitude during a United Airlines flight from Lagos, Nigeria, to Washington, D.C., early Friday, officials said.

The same United Airlines aircraft had a similar issue earlier this week, with a rapid altitude drop prompting a diversion.

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.

The US National Transportation Safety Board is investigating a United Airlines Holdings Inc. flight that turned back to Nigeria after a “sudden aircraft movement” occurred, injuring passengers and crew.

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

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,