Dutch investigators say they were unable to conclusively identify the cause of a 2018 serious incident in which 23 passengers and cabin crewmembers became ill, causing the pilots of their United Airlines Boeing 767-300ER to return to Amsterdam about an hour after departure on a flight to Newark, New Jersey.
No Cause Found for Ailing Passengers, Crew on United Transatlantic Flight
Boeing concluded the problem likely was a result of ‘degraded and uneven airflow and/or temperature control issues in the cabin.’