What happened
On February 24, 2022, an Embraer E190AR, registration LV-GIQ, operated by Aerolíneas Argentinas, was performing a scheduled commercial flight from Aeroparque Jorge Newbery to Río Gallegos. During the climb, the aircraft entered icing conditions, which triggered the automatic anti-ice system.
As the aircraft reached flight level 260, the crew received a "Bleed #1 Fail" alert. Shortly after, near flight level 280, a second alert, "Bleed #2 Fail," appeared on the Engine Indicating and Crew Alerting System (EICAS). In response to these failures, the crew began a descent to flight level 100. However, while passing through flight level 210, a "Cabin Altitude Hi" alarm activated. This prompted the crew to execute an emergency descent and divert the aircraft to Ministro Pistarini International Airport (Ezeiza). The aircraft landed safely at 12:56 UTC, with no injuries reported among the 105 occupants.
The investigation
The investigation focused on the pneumatic system and the reliability of its components. Investigators examined the condition of the High Pressure Shutoff Valves (HPSOV) and the Fan Air Valve (FAV). The analysis revealed that the left-side pneumatic failure was caused by extreme wear, corrosion, and electrical overdemand within the left engine's HPSOV. Additionally, the right-side system's failure was linked to the condition of the Fan Air Valve, which showed mechanical play due to a worn carbon bushing.
Findings
- The primary cause of the incident was a dual failure of the pneumatic bleed air systems.
- The left-side failure originated from severe corrosion and electrical overdemand in the HPSOV.
- The right-side failure was likely caused by a malfunctioning Fan Air Valve.
- The simultaneous loss of both bleed systems led to the cabin altitude warning.
- The investigation identified a broader reliability concern, noting that the specific component (P/N 1001246-3) used in these valves has a high rate of unscheduled removals globally.
- The operator and other global operators have experienced similar dual-failure events in this aircraft model.
Safety action
- ASO AE-172-24: Emphasized the need for proactive maintenance programs based on real-world reliability data to mitigate risks from components that may face operational demands beyond their original design intent.
- ASO AE-173-24: Highlighted the necessity of proper cockpit voice recorder management to prevent data overwriting, which can hinder the accuracy of accident investigations.