Flight aborted in midair after pilots missed cabin pressure error, investigation finds | CNN
A plane full of holiday travelers had to turn back mid-flight due to a technical error that caused the cabin to lose pressure.
An official investigation into the event that occurred last year revealed that the 193 passengers aboard the Tui Airways flight from Manchester Airport in the UK to Kos, Greece, "faced the danger of hypoxia."
On October 17, 2023, a cabin altitude alert went off on the Boeing 737-8K5 while the aircraft was flying over Lincolnshire in eastern England.
The aircraft flew back to Manchester without any injuries reported. However, a report from the Air Accidents Investigation Branch (AAIB) indicated that the passengers on board may have faced a danger of declining oxygen levels during the situation.
The investigation found that the bleed air switches, which control the air pressure in the aircraft, were switched off during maintenance on the air conditioning system before the flight. This mistake went unnoticed by the crew during their pre-flight safety checks.
An engineer involved in the maintenance of the aircraft informed investigators that he thought the switches had been "put back in their original place" after inspecting the jet's air conditioning system. However, another engineer did not notice that the switches were actually turned off.
The pilots also failed to notice the oversight, both prior to departure and during the checks conducted after takeoff, according to the report.
After the error occurred, the pilots switched the systems back on. However, the report indicated that the crew did not follow additional steps outlined in the Quick Reaction Handbook (QRH) to address the alert. One of those steps included putting on oxygen masks.
The report indicated that the pilots believed simply flipping the switches would fix the problem and that taking additional actions would be overly excessive.
The report stated that putting on the oxygen masks right away would have shielded both pilots from the danger of hypoxia and enabled them to assess the situation more clearly once that major risk was eliminated.
After the switches were switched back on, the plane kept ascending. However, the warning light stayed illuminated for 43 minutes before the crew decided to pause and reach out to the Tui maintenance team at Manchester Airport, according to the report. The captain ultimately chose to head back to Manchester.
Cerebral hypoxia occurs when the brain does not get enough oxygen. This can happen if an aircraft flies at too high an altitude or if the cabin pressure drops. It can also be caused by inhaling carbon monoxide or excessive smoke from a fire.
The Federal Aviation Administration notes that each pilot experiences hypoxia in their own way. However, recognizing when it occurs can be quite challenging, as the initial signs are often very subtle.
CNN contacted Tui for a response.
This report includes contributions from Jen Christensen at CNN.
