Introduction
In April 2025, the European Union Aviation Safety Agency (EASA) released SIB 2025-02 addressing a growing concern in the aviation sector: nuisance alerts from Emergency Locator Transmitters with Distress Tracking capabilities (ELT(DT)). These false alerts are not just operational disruptions—they now require mandatory occurrence reporting (MOR). This article explores the implications of EASA’s guidance, necessary actions for CAMOs, MOs, and operators, and how to align documentation like the CAME and MOE to ensure compliance.
Understanding SIB 2025-02 Context
ELT(DT) systems were introduced to enhance aircraft tracking in distress situations, specifically to comply with ICAO Annex 6, Part I, Section 6.18 and Commission Regulation (EU) 965/2012, Annex IV, CAT.GEN.MPA.210. These systems are designed to transmit aircraft location data immediately before impact, using automated sensors and flight parameters.
However, a surge in nuisance alerts—unintentional activations—has prompted EASA to act. These alerts often occur due to inappropriate handling during maintenance or system design flaws. Unlike traditional ELT(AF) devices, ELT(DT)s transmit distress signals almost instantly upon activation, amplifying the risk of false alerts.
One of the most significant takeaways from the SIB is that all ELT(DT) nuisance activations must now be reported as if they were Mandatory Occurrence Reports (MORs).
Implications for CAMOs, AMOs and Operators
The implications are wide-ranging. Organisations must:
- Update the CAME and MOE to include guidance on ELT(DT) testing, activation, and reporting.
- Educate staff on the ELT(DT)’s sensitivity, particularly during power-on, airborne simulation, or configuration changes.
- Ensure that testing procedures only involve designated test switches and include electromagnetic shielding when necessary.
Design Approval Holders (DAHs) are now obliged to provide post-flight data logs to identify what triggered ELT activations, supporting accurate root cause analysis.
Case Examples and Technical Triggers
Nuisance activations may occur during:
- Aircraft placed on jacks for maintenance
- Airspeed/altitude simulations
- Power shutdowns of key avionics
- Manual ELT switch toggling, even for a few seconds
Each incident diverts Search and Rescue (SAR) resources, causes ATC disruptions, and burdens operations unnecessarily. Immediate reset and notification to Mission Control Centres and RCCs is essential.
Recommended Actions for Compliance
To align with SIB 2025-02, Operators, production organisations and approved maintenance organisations should take measures so that their personnel are aware that:
- Setting the ELT in manual mode even for a few seconds (most often labelled “ON”) position from the cockpit ELT control panel result in immediate transmission for ELT(DT);
- Should a nuisance alert be transmitted, the nearest Mission Control Centre, Rescue Coordination Centre and Air Traffic Services unit for the location of the alert transmission should be advised so that no SAR resources will be deployed. This can be done through the contact identified in the following page of COSPAS-SARSAT website: Inadvertent Alerts - International COSPAS-SARSAT
- Any unintended ELT alert should be stopped as early as possible, either by resetting the ELT (for alerts resulting from the distress logics) or by using the ELT switch (for alerts generated by the manual activation switch or by the crash acceleration sensor). In all cases, all ELT activations should be terminated before the aircraft takes off;
- Testing should be undertaken only by using the test-switch position intended for that purpose. If activation of the distress-switch function is required, electromagnetic shielding of the beacon antenna should be considered prior to the “live” distress-switch-activated test;
- Aircraft maintenance and production activities (e.g., troubleshooting stimulating aircraft systems) should follow the DAH instructions to avoid nuisance activations. Furthermore, the absence of ELT activation should be checked (e.g., through the dedicated cockpit indication or a 406 MHz monitoring device) regularly during and after production and maintenance tests during which the avionics equipment is powered on.
Conclusion
SIB 2025-02 represents a pivotal shift in how the aviation industry addresses ELT(DT) alerts. These systems, vital for safety, require disciplined handling and robust reporting. With nuisance alerts now considered as if they were MORs, updating internal documentation and procedures is not just best practice—it's essential for regulatory compliance and operational integrity.
The referenced EASA-published Safety Information Bulletin 2025-02 can be downloaded from EASA’s Safety Publications Tool : https://ad.easa.europa.eu/blob/EASA_SIB_2025_02.pdf/SIB_2025-02_1
