Air Baltic Writes Off A220-300 Following APU Ground Fire Incident

Air Baltic has confirmed it will write off an Airbus A220-300, registered as YL-AAO, following significant damage from a fire during ground maintenance. The decision marks the first confirmed hull loss for the A220 program since its commercial introduction in 2016. The incident, which involved an APU ground fire, occurred at Riga Airport on June 14, 2025, while the aircraft was undergoing reactivation procedures after a period of prolonged storage.

The event raises new questions regarding maintenance protocols for new-generation aircraft, particularly those returning to service after extended groundings. According to Air Baltic's financial disclosures, the write-off will result in a net negative financial impact of €6.2 million, even after a $33.4 million insurance settlement was paid for the aircraft.

Incident Details and Investigation

The fire started during a ground run of the aircraft's Honeywell 131-9C Auxiliary Power Unit (APU), a standard procedure following heavy maintenance. The investigation traced the origin of the fire to the ozone filter within the Environmental Control System (ECS). An uncontained failure within the APU reportedly led to the subsequent fire, which caused substantial thermal and structural damage to the aft fuselage of the aircraft.

At the time of the incident, the six-year-old aircraft, delivered in March 2019, was being prepared to re-enter service. It had been in storage since September 2024 due to the widespread Pratt & Whitney PW1500G engine availability issues that have affected A220 operators globally. Air Baltic has stated that the Maintenance, Repair, and Overhaul (MRO) work was performed strictly in accordance with all applicable regulations and that its investigation found no evidence of human error by its technicians.

Following a detailed assessment, Airbus Engineering concluded in December 2025 that restoring the aircraft was not economically viable, leading to the hull loss declaration. The Latvian Civil Aviation Agency is conducting a standard occurrence investigation to determine the root cause, which will clarify whether the fire resulted from a maintenance error or a component design flaw.

Financial and Industry Impact

The loss of YL-AAO has direct consequences for several key stakeholders. For Air Baltic, the primary operator of the A220-300, it represents the permanent loss of a key fleet asset and a financial hit of €6.2 million. Aviation insurance underwriters are also significantly affected, having paid out a $33.4 million settlement. For the Airbus A220 program, the incident is a notable blemish on an otherwise strong safety and operational record, requiring engineering resources to analyze potential risks associated with the ECS and APU components.

This ground-based hull loss of a modern composite-rich aircraft draws comparisons to previous events. In July 2013, an Ethiopian Airlines Boeing 787-8 suffered a severe ground fire at London Heathrow due to a faulty emergency locator transmitter battery. However, that aircraft was ultimately repaired and returned to service. In contrast, this A220 incident more closely mirrors the outcome of a hangar fire in April 2007 that destroyed a Qatar Airways Airbus A300-600 during heavy maintenance, which was also written off.

Technical Analysis

The write-off of YL-AAO underscores a growing industry focus on the complexities of maintaining next-generation aircraft. The fact that the first hull loss for the A220 program occurred on the ground during MRO activities, rather than in flight, shifts scrutiny toward ground procedures, component reliability, and the potential for unforeseen risks during reactivation after long-term storage. The aircraft's preceding grounding due to engine supply chain issues introduces a critical variable; industry safety analysts have suggested that prolonged inactivity and the subsequent intensive reactivation process may introduce stresses or conditions not typically encountered in routine operations. This event may accelerate a trend toward more prescriptive MRO guidelines from manufacturers and regulators, especially for systems like the APU and ECS that are heavily used during ground checks.

What Comes Next

The industry now awaits the final investigation report from the Latvian Civil Aviation Agency, which is expected to be released in late 2026. The findings will be crucial in determining if any airworthiness directives or changes to maintenance procedures are required for the global A220 fleet. The report will likely focus on the Honeywell APU's performance and the specific failure mode of the ECS ozone filter.

Why This Matters

This incident is significant as it represents the first hull loss of a highly successful and modern aircraft program, the Airbus A220. It places a spotlight on the potential vulnerabilities associated with ground maintenance procedures, particularly when reactivating aircraft after extended storage. For operators, manufacturers, and MRO providers, this event serves as a critical case study on the unforeseen risks of complex, integrated systems on new-generation airliners.

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