A flight packed with vacationers had to be aborted in midair because a technical mistake meant the aircraft failed to pressurize . An official report into the incident last year found that the 193 people on board the Tui Airways flight from Manchester Airport in the United Kingdom to Kos in Greece “were exposed to the risk of hypoxia.” A cabin altitude warning was activated in the Boeing 737-8K5 on October 17, 2023 as the plane flew over Lincolnshire in eastern England.
The plane returned to Manchester and there were no injuries but the report from the Air Accidents Investigation Branch (AAIB) said that those on board were likely to have been at risk of dropping oxygen levels during the incident. The investigation revealed that switches that regulate the air pressure inside the plane, known as bleed air switches, were turned off during maintenance work carried out on the air conditioning system before takeoff. This error was not picked up by the crew in their pre-flight safety measures.
One of the engineers who carried out the maintenance work on the plane told investigators that he believed the switches had been “returned to their original position” after checks on the jet’s air conditioning system. A second engineer failed to spot that they were, in fact, in the off position. The oversight was also not detected by the pilots, either before takeoff or during “after takeoff checks,” the report found.
Once the error emerged, the pilots turned the switches back on.