### Tui Airways Flight Aborted Due to Pressurization Error

A Tui Airways flight carrying 193 passengers from Manchester Airport in the United Kingdom to Kos, Greece, was forced to abort midair due to a technical oversight that caused the aircraft to fail to pressurize. An investigation by the Air Accidents Investigation Branch (AAIB) revealed that the passengers and crew were at risk of hypoxia, a condition caused by low oxygen levels.

The flight, which originated from Manchester, returned to the airport without any injuries reported. According to the AAIB report, the issue stemmed from bleed air switches that control air pressure within the aircraft. These switches had been turned off during maintenance on the air conditioning system and were not switched back on before takeoff. The maintenance engineers claimed that they believed they had returned the switches to their original positions, but a second engineer failed to verify this.

Neither the maintenance crew nor the pilots detected the error prior to departure or during the initial after-takeoff checks. When the problem was finally noticed during flight, the pilots switched the bleed air switches back on. However, they did not follow the complete procedures outlined in the Quick Reaction Handbook (QRH), such as donning oxygen masks, which would have protected them from hypoxia risk while they assessed the situation.

The report indicated that the pilots may have considered putting on oxygen masks and following other QRH procedures to be unnecessary after reactivating the switches. The aircraft continued to climb despite the warning light remaining on for 43 minutes. The decision to halt the climb and consult with Tui's maintenance team at Manchester came later, prompting the captain to decide to turn back.

Cerebral hypoxia, which occurs when the brain is deprived of oxygen, can be triggered by high altitudes or loss of cabin pressure. It can also result from situations like carbon monoxide poisoning or inhaling smoke. The Federal Aviation Administration notes that hypoxia symptoms can be deceptive and vary greatly among individuals, making it difficult to self-diagnose.

The AAIB report underscored the critical nature of adhering to safety protocols and the necessity of thorough checks in maintaining aircraft safety.