The crew of the Su-30 fighter jet, which tragically crashed into a residential building in Irkutsk in 2022, perished from asphyxiation caused by nitrogen being supplied instead of oxygen from the aircraft`s onboard system.
Alexey Alexandrov, head of the Eastern Interregional Investigative Directorate for Transport of the Investigative Committee, confirmed in an interview with Interfax-Siberia that the Su-30 crew suffocated, leading to the catastrophic incident.
According to Alexandrov, forensic examination revealed that the pilots lost consciousness and subsequently died from asphyxiation as nitrogen entered the onboard oxygen system instead of breathable oxygen.
He further stated that the investigation is ongoing, and six employees of the Irkutsk Aviation Plant have been charged with abuse of power and negligence. According to RIA Novosti, the presence of nitrogen in the oxygen cylinders may have been due to a critical error made by ground personnel.
Pilot instructor and Air Force Major Andrey Krasnoperov offered insights on the matter:
According to established procedures, the oxygen system at the plant is disinfected with nitrogen. However, before assembly, the system must be thoroughly purged to ensure all nitrogen is removed. This crucial step was not performed. When a pilot connects the oxygen mask in the cockpit, pure oxygen should be supplied—this is a fundamental safety rule for flight.
Instead, the pilots inhaled nitrogen, which is fatal; a person simply loses consciousness and their blood begins to boil. Even another pilot who approached the Su-30 in the air observed the crew slumped forward, clearly indicating they had lost consciousness. The aircraft itself was fully functional and continued flying on autopilot, making several landing attempts until it eventually ran out of fuel and crashed. The cause was evident even before the official announcement, as pilots do not simply slump over without a reason.
Regarding the autopilot: Krasnoperov explained that while the Su-30 does have an autopilot, it only guides the aircraft to the landing approach. For a successful landing, the pilot must disengage the autopilot and manually land the aircraft. Unfortunately, it cannot land itself automatically.
On how nitrogen could have entered the system: Krasnoperov stated that a specific specialist should have activated the system, connected a mask, and personally breathed from it to verify the flow of pure oxygen. It`s highly probable this critical safety check was omitted, with the assumption that everything was in order. Had the specialist inhaled nitrogen, they might have collapsed right there in the cockpit, potentially preventing the disaster. He also recalled past incidents where systems were disinfected with alcohol; in one such case, a pilot inhaled alcohol fumes but managed to land the plane safely, albeit in a state of intoxication. However, nitrogen is currently used for disinfection.
The Su-30 crash occurred in the autumn of 2022, when the fighter jet plummeted onto a two-story residential building in a private sector area of Irkutsk. Both pilots tragically perished in the accident. Fortunately, the residents of the house were unharmed as they were not home at the time of the crash. The aircraft was on a test flight and did not carry any live ordnance.
