'Serious incident' on TUI plane leaving Manchester Airport with 187 people bound for Greece, report finds

Crew and passengers were put at risk when TUI plane suffered a serious mid-air cabin pressure incident over the UK, accident investigators said. At the time, 187 passengers were on board as it flew from Manchester Airport to Greece.

After taking off from Manchester, the aircraft failed to pressurise and those on board were exposed to the risk of hypoxia - low levels of tissue oxygen, a report found. The incident happened three days before the same plane suffered an unrelated “catastrophic failure” while landing at Leeds Bradford Airport during a storm.

The Manchester flight was en route to Kos Airport after taking off at 6.06am on October 17 last year, Hull Live reports. After just six minutes, a cabin altitude warning went off in the Boeing 737-8K5 above the Humber area.

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This alerted crew to a “serious incident”, the Air Accidents Investigation Branch (AAIB) said in report published this month. The report stated: “A cabin altitude warning was activated as the aircraft passed FL130 (13,000ft). Both engine bleed air systems had been inadvertently left off for the departure, so the aircraft failed to pressurise.”

Investigators found the plane’s air systems had been turned off by engineers during routine maintenance work - they said “it appears” the systems had not been switched back on. After the crew then turned both systems on, the aircraft continued its climb. However the plane generated a further caution and it stopped climbing at 20,000ft.

Following consultations with the operator’s maintenance control, the plane’s commander decided to return to Manchester Airport. As the plane was above the maximum landing weight, it had to go into a holding pattern to burn fuel before it could land. The situation was explained to the passengers over the public address system.

The AAIB report said: “The recorded data indicated that the cabin altitude warning remained on for 43 minutes. During that time the associated red warning light should have been illuminated, though neither pilot recalls seeing it.

“As the passenger oxygen masks did not deploy, the cabin altitude did not exceed 14,000ft. Nevertheless, it was likely that the crew and passengers were exposed to a progressive hypoxia risk. While any loss of consciousness was highly unlikely, a negative impact on the ability of the crew to process information and make decisions was probable.” Join the North Wales Live WhatsApp community group where you can get the latest stories delivered straight to your phone

The report continued: “As the aircraft did not pressurise, the crew and passengers were exposed to the risk of hypoxia. At cabin altitudes above 10,000ft but below 14,000ft, without the pre-existence of significant medical issues, the likelihood of loss of consciousness is very small.

“However, in this altitude window, the hypoxic exposure can be sufficient to affect cognitive performance and decision-making to the point where the decline would be observable in cognitive tests. In this range of altitudes there are many variables that affect the severity and impact of hypoxia, including duration of exposure, rate of hypoxia onset (eg rate of climb if no pressurisation), physical workload, fatigue, individual responses and type of task being performed.

“In this range of altitudes it is also difficult to separate the relative contribution of hypoxia versus other performance degraders such as fatigue, distraction or other human performance issues.” The plane landed safely at Manchester Airport at 8.10am with no injuries.

Neither of the pilots were originally scheduled to operate the service and both were rostered for a standby duty starting at 3am, according to the report. The commander was awoken by a notification on his smartphone roster app at 1am indicating he had been assigned the Manchester-to-Kos flight. The co-pilot was notified by a phone call from crewing at 2.30am. Both pilots were given a report time of 4.30am.

The AAIB report notes that while the commander did not believe fatigue was a factor in this event, analysis of his roster over the previous eight weeks suggested fatigue could have been a contributory factor. This showed that the commander’s exposure to ‘fatiguing duties’ was among the highest across the operator’s B737 fleet and joint highest amongst its commanders at Manchester.

In an unrelated incident, three days later the plane came off the runway at Leeds Bradford Airport during Storm Babet. An AAIB investigation into this event found that one of the aircraft’s nosewheel bearings had “suffered a catastrophic failure”. The aircraft sustained minor damage and there were no injuries. TUI was approached for comment. Sign up for the North Wales Live newsletter sent twice daily to your inbox