INCREASED MAINTENANCE INTERVALS FOR ATR DE-ICING

COMPONENTS FOLLOWING EASA DIRECTIVE:

A BROADER LOOK AT INSPECTION REQUIREMENTS IN AVIATION SAFETY

The European Union Aviation Safety Agency (EASA) has mandated more frequent inspections of the pressure regulator and shut-off valves (PRSOV) in ATR turboprops, following a design review conducted with ATR. These valves play a crucial role in regulating engine bleed air for airframe and engine de-icing, ensuring safe operations in icing conditions. The directive, effective as of January 24, 2025, reduces the intervals between functional tests to mitigate the risk of losing anti-icing protection for the engines’ air intakes.

According to the directive, functional checks must now be performed at intervals ranging from 650 to 1,050 flight hours, depending on the ATR model. All ATR aircraft are required to undergo their first inspection within the next six months. ATR has proactively communicated updated maintenance procedures to all operators, ensuring that the functional testing of affected components is performed in accordance with regulatory guidelines. The manufacturer has also stated that there have been no reported in-service failures related to this issue.

Lessons from the Voepass Linhas Aéreas Flight 2283 Incident

The push for increased inspection intervals and enhanced maintenance protocols has been reinforced by the fatal accident of Voepass Linhas Aéreas Flight 2283 in August 2024, which involved an ATR 72-500. The aircraft was operating in severe icing conditions, and preliminary investigations by Brazil’s Center for Research and Prevention of Aeronautical Accidents (CENIPA) indicated that its ice detection system had been triggered multiple times before the crash. Cockpit voice recordings captured crew discussions about significant ice accumulation shortly before the aircraft lost control.

While the final report on the accident has not been issued yet, the incident has highlighted the critical importance of de-icing system functionality in ATR aircraft and turboprops in general. It has also reignited discussions on whether current de-icing protocols and maintenance schedules are sufficient in the face of extreme weather conditions.

Expanding Inspection Frequency to Other Critical Systems

The increased inspection requirements for ATR de-icing components reflect a broader trend in aviation safety regulations, where frequent and proactive maintenance practices help prevent catastrophic failures. Several other aircraft components and systems have also been subject to revised maintenance schedules due to safety concerns, including:

Flight Control Systems – Issues with stabilizer trim, rudder movement, and aileron actuators have led to the need for closer monitoring of hydraulic and electrical components in recent years.

Engine Components and Oil Systems

Uncontained engine failures and oil degradation risks have prompted regulatory bodies to mandate more frequent borescope inspections and engine oil analysis to prevent failures.

Landing Gear and Brake Systems Extended wear-and-tear from frequent operations has resulted in new requirements for shock absorber inspections, hydraulic line checks, and brake wear monitoring.

Electrical and Avionics Systems – As modern aircraft become increasingly dependent on automated flight control and electronic systems, regular software updates and functional tests have become necessary to prevent failures in navigation and communication systems.

The Importance of Proactive Maintenance in Aviation Safety

EASA’s latest directive underscores a fundamental principle in aviation safety: maintenance should be preventive rather than reactive. By implementing shorter inspection intervals and more rigorous testing of critical components, aviation authorities can detect early signs of component failure before they become safety risks.

With increasingly unpredictable weather conditions due to climate change, it is expected that aircraft will encounter more severe icing conditions, turbulence, and temperature fluctuations in the coming years. Airlines and operators must remain adaptable and prioritize compliance with updated maintenance directives to ensure the safety and airworthiness of their fleets.

The ATR PRSOV inspections serve as a crucial reminder of how seemingly minor component failures can have severe consequences. By addressing potential issues before they escalate, aviation regulators and manufacturers continue to uphold the highest standards of safety in global air transport.

References

Centro de Investigação e Prevenção de Acidentes Aeronáuticos (CENIPA). (2024, September 6). Preliminary Report on the Accident Involving Voepass Linhas Aéreas Flight 2283. Retrieved from dedalo.sti.fab.mil.br

European Union Aviation Safety Agency (EASA). (2025). Airworthiness Directives & Maintenance Bulletins. Retrieved from easa.europa.eu