A TUI plane with 193 people onboard was forced to make an emergency landing to avoid passengers and crew passing out from a lack of oxygen.
It was discovered after the Boeing 737 took off from Manchester to Kos in Greece that switches to pressurise the plan had been accidentally left turned off during maintenance.
The pilot spotted the error only after the plane had started its ascent and though he immediately turned the engine bleed air system on, a further alert forced the aircraft to return to Manchester, where it landed safely with no injuries.
A report into the incident by the Air Accident Investigation Bureau (AAIB), published last week, found that pilot fatigue might have been a contributing factor.
Neither of the pilots was originally due to operate the flight on 17 October last year but the captain was woken by a call at 1am and the co-pilot was called at 2.30am, both being told to report for duty at 4.30am.
While neither the 53-year-old captain or his co-pilot reported feeling tired, the report by the AAIB said both had been working ‘harder than usual’.
It added: “In terms of acute fatigue, the duty itself was not particularly fatiguing, but the commander’s pre-duty rest was disturbed with just three hours sleep achieved.
“There were several indicators from the analysis of the previous eight weeks that suggested chronic fatigue was a possible factor for the commander.
“He had carried out a significant number of overtime duties and, although they were not necessarily individually fatiguing, the cumulative disruption may have been a factor.”
The AAIB fond the captain’s exposure to fatiguing duties was the joint highest among TUI’s captains at Manchester.
The report added: “It should be noted that fatigue, particularly chronic fatigue, can be insidious such that an individual may not recognise the symptoms in themselves.”
Three days later, the same plane veered off the runway while landing in bad weather at Leeds Bradford Airport. An AAIB investigation revealed that one of the aircraft’s nosewheel bearings had ‘suffered a catastrophic failure’ during Storm Babet.
The incident resulted in minor damage to the aircraft, but no injuries were reported.
