Lessons Learned: Ditching Pushbutton Leads to Lack of Pressurization
A flight crew was alerted to a lack of pressurization due to the engagement of the ditching pushbutton.
The crew left the ditching pushbutton selected when reconfiguring the aircraft from the de-icing checklist. With the ditching pushbutton selected, the aircraft did not pressurize and the cabin altitude slowly increased as the aircraft climbed to its cruise altitude of FL390. The crew was alerted to the increasing cabin altitude, and an emergency descent was performed.
During this procedure, the commander noticed the ditching pushbutton was on; once the ditching pushbutton was deselected, the aircraft pressurization returned to normal. The aircraft was leveled at FL200 and, after some analysis, the crew determined that they could continue with the flight to their destination. The aircraft climbed up to FL370 and the rest of the flight was completed without further incident.
The operator and the manufacturer have taken safety action to raise awareness of the event and to amend the de-icing checklist.
History of the flight
The flight crew was operating an early morning scheduled service from Belfast Aldergrove airport (Belfast) to Palma de Mallorca airport, Spain (Palma). The flight was a training flight for the co-pilot, who had completed 36 of the planned 50 training sectors. The aircraft had arrived late from its previous flight that morning. A
s the flight crew walked toward the aircraft, the commander noticed what appeared to be ice on the upper surfaces of the wings, fuselage, and stabilizer. Once the crew was seated, the commander took a few minutes to settle the co-pilot. He explained the aircraft would probably need to be de-iced; a process which the co-pilot had not experienced before. In addition to completing the regular pre-flight procedures, the flight crew needed to configure the aircraft for de-icing before the de-icing crew arrived. The commander used the relevant checklist in the Quick Reference Handbook (QRH), which was available to both crew members on their electronic tablet devices, to configure the aircraft. The de-icing crew arrived and performed a tactile check, reporting to the commander there was no longer any requirement to de-ice.
Therefore, the flight crew began to reinstate the configuration of the aircraft referencing the checklist but, in doing so, omitted to return the ditching pushbutton to off.
Content/image source/credit: AAIB (Air Accidents Investigation Branch), “AAIB investigation to Airbus A320-251N, G-UZEF,” published January 8, 2026.
