Pilot began emergency descent on Edinburgh-bound flight after warning sounded in cabin

A flight bound for Edinburgh was forced to begin an emergency descent after a loss of cabin pressure, an investigation has found.

The cargo service left East Midlands airport (EMA) on May 17 this year heading for Edinburgh with two crew members on board.

The Boeing 737 aircraft’s cabin altitude warning sounded, prompting the flight crew to don oxygen masks and execute an emergency descent.

The Air Accidents Investigation Branch (AAIB) concluded that a quantity of dry ice formed part of the cargo load.

The aircraft’s air conditioning pack control switched to the high position, which the commander described as “an unusual [pack] configuration.”

After levelling off, the commander checked the overhead panel and found both pack switches were selected off.

Switching them back on restored pressurisation and the flight continued towards Edinburgh.

The AAIB described the incident as “serious”.

The report stated: “The commander was convinced they left EMA with the packs operating and had not noticed any switches out of place when conducting a scan of the overhead panel at the top of climb.

“He concluded the switches must have been selected off during flight; however, neither he nor the co-pilot recalled doing so.

“The commander considered it possible the switches had initially been in the normal on position and that the wrong ‘unusual configuration’ (ie off rather than high) had been selected to ‘correct what [they] perceived as a mistake’.”