The US Federal Aviation Authority has ordered inspections of Boeing 737-700, 800, 900ER and Max aircraft which are in common use in North America, particularly for domestic services.
More than 2,600 aircraft are affected by an issue whereby oxygen generator units can shift in flight, potentially cutting off supplies if they are needed.
UK carriers including Ryanair and Tui use some of the 737 types affected, but there has so far been no edict from Europe’s safety regulators.
The FAA said its order “was prompted by multiple reports of passenger service unit oxygen generators shifting out of position because of a retention failure”.
Boeing’s 737 is already under the spotlight after a door plug blew out on an Alaska Airlines flight in January, prompting regulators to order a safety overhaul.
In April, a whistleblower raised concerns about Boeing’s long-haul aircraft, claiming shortcuts were compromising build quality of its 777 and 787s.
