Depressurization is unlikely to cause this. There is no subtle way it happens. The first steps are for the pilots to don oxygen masks at forced 100% flow, then use the autopilot to descend to an altitude no lower than 10,000 feet.
This event had a trigger event at 38,000. A controlled descent means that the pilots were conscious. An Airbus is one of the few modern aircraft that will NOT begin a descent without direct crew initiation. A little known fact for all the Airbus-bashes out there. You cannot program an Airbus to fly a descent profile and have the aircraft automatically initiate it. It always takes a pilot to execute a descent. Period.
The possible trigger events point to either an airframe structural failure at altitude or fire/smoke. It had to be something to disable BOTH the crew and the automation.
What kind of structural failure might occur?
This happened to a United flight I was on in 1987. Chicago to Spokane. We were cruising at 35m’ over ND. We felt a pop in our ears. The captain put the jet in a nose drive for 15 minutes. We leveled out at 10m’. The O2 masks worked in the cockpit, but did not deploy in the main cabin. We made an unscheduled landing in Billings, MT. Myself and 4 others got flights out that same day through Denver and Salt Lake to end up Spokane. The remainder of the passengers spent the night in Billings. They grounded the aircraft, a Boeing 737.
When we came to a halt in front of the terminal in Billings, the pilot came out of the cockpit and we gave him a standing ovation. It made the national news.
Comforting if true.
I believe that you, as a highly skilled A320 pilot, firmly believe that.
I wonder if a highly skilled programer would always have the same belief.