Electronic warfare training and spectrum testing are critical for military readiness. At the same time these activities present clear and quantifiable risks to civil aviation when they affect Global Navigation Satellite Systems and other aeronautical radio services. ICAO already frames the problem: Member States are urged to refrain from jamming or spoofing that affects civil aviation and to coordinate defence-related operations that could cause interference.

ICAO guidance and Assembly resolutions emphasize two principles that must govern any policy on EW exercises. First, safety of civil aviation is paramount. Second, military and State activities that might affect air navigation must be coordinated with civil authorities and ANSPs to the maximum extent practicable. These are not optional recommendations in practice, they are the operational baseline.

What States have done so far shows pragmatic mitigations that should be captured in formal ICAO policy. National Aeronautical Information Circulars and NOTAMs routinely notify airspace users when GNSS jamming trials will occur, give geographic and altitude exposure estimates, set daily time windows, and publish emergency contact numbers to request a cease of jamming if safety-critical operations require it. The UK examples around Sennybridge provide concrete templates for what responsible notification looks like.

Similarly, when exercises include GNSS disruption the military often schedules limited daily windows, restricts the duration of individual jamming serials, and issues repeated NOTAM updates so operators can plan reversion to conventional navigation. France published such restrictions during its large Black Crow exercise in 2024 and accompanied the activity with repeated NOTAMs and stakeholder briefings. These practical measures materially reduce risk when properly executed.

Policy gaps still remain at the international level. ICAO can close those gaps by converting good national practice into harmonized, prescriptive guidance and templates. Below I list a concise set of policy requirements that would be practical to adopt, and that map to observable practices already in the field.

Mandatory pre-exercise coordination and notification

  • Require a formal notification package to be published as an Aeronautical Information Circular at least 30 days before any EW activity that could affect civil aviation. The package should include the purpose of the activity, geographic coordinates, worst case impact footprint by altitude, frequencies and bands affected, maximum transmit power, daily windows and expected serial durations, and the name and 24/7 contact point for an emergency cease. This mirrors the effective elements used in published national AICs and NOTAMs.

  • Require parallel coordination with the national spectrum regulator and law enforcement so that any unauthorized or accidental broader interference can be tracked and mitigated quickly. ICAO has already called for stronger civil military and spectrum authority collaboration and this formalizes that requirement.

Operational constraints and safety controls

  • Limit jamming/spoofing serials in civil airspace to short predefined bursts, with maximum numbers of serials per hour and mandatory quiet periods. Where national practice exists, states already limit serial duration and number to keep cumulative exposure predictable. Those numerical limits should be standardized and based on technical modelling of worst case coverage.

  • Require exclusion of dense terminal airspace and major IFR corridors except under tightly controlled and negotiated conditions. When testing must occur near busy airspace, require ANSPs to provide temporary contingency procedures and additional controller staffing. ICAO manuals on civil military coordination already recommend that military activities be scheduled to avoid peak civil traffic.

Monitoring, real time mitigation and emergency response

  • Mandate that exercises with GNSS or C2 jamming be accompanied by real time spectrum monitoring that is visible to a designated civil authority. Monitoring should include on site spectrum sensors and a public or semi-public feed to ANSPs to show when and where interference is active. National exercise notices in the UK and France show the value of linking exercise windows to real time NOTAM updates.

  • Require a clearly published emergency cease procedure and a 24/7 operational phone line or data channel managed jointly by the exercise commander and the ANSP. The UK trials provide a model where a formal cease contact is published for safety of life callouts.

Redundancy, contingency planning and reporting

  • States should demonstrate that a Minimum Operational Network of conventional navaids will be available to support reversion should GNSS become unavailable. ICAO and EASA have both urged maintenance of conventional navigation infrastructure as part of GNSS resilience planning.

  • Require operators and ANSPs to include GNSS interference contingencies in their Safety Management System. Exercises should include scenario-based validation of ATC contingency procedures and airline SOPs for GNSS loss so that real world disruptions are manageable. The industry push for harmonized SOPs highlights the operational necessity of this element.

  • Standardize an incident reporting format so that all GNSS interference events during exercises are logged in a way that allows aggregated analysis and rapid feedback to the civil aviation community. Better data drives better mitigation and regulatory adjustments.

Legal, enforcement and export controls

  • ICAO should work with ITU and national regulators to tighten controls on the export, sale and illicit use of jammers and spoofers that are likely to appear in exercises and then leak into the civilian market. The joint ICAO, ITU and IMO statement of 2025 flagged the need for strengthened protections for RNSS bands. Aligning aviation requirements with spectrum enforcement reduces accidental and malicious incidents.

Templates, training and certification

  • Publish ICAO templates for AICs and NOTAMs specific to EW activities. A standard form reduces ambiguity and enables automated ingestion by airline and ANSP systems. Examples from national AICs provide fields that should be mandatory such as frequency bands affected, altitude layers, serial timing and emergency contacts.

  • Require that militaries and contractors performing EW tests demonstrate trained spectrum managers and an operational safety officer with aviation experience. Exercise certification should include a documented safety case showing mitigation measures for civil aviation. This reduces human factors errors that create unexpected interference footprints. ICAO manuals that cover civil military safety measures already point to the need for structured civil military coordination.

Practical guidance for operators and ANSPs

  • Treat any published EW exercise as a predictable GNSS degradation event. Validate reversion procedures on flight simulation and ATC simulators. Update SOPs to include explicit steps for an inflight GNSS degradation in terminal area operations. Operators in regions with frequent GNSS events have already adopted such measures and they reduce pilot workload and ATC confusion when signals are lost.

  • ANSPs should publish contingency routes and increased vectoring capacity during exercise windows and ensure that adjacent FIRs are aware of potential spill. Real time monitoring feeds discussed above are essential to manage the traffic flow impacts.

Closing recommendation

The evidence from recent practice is clear. States can conduct legitimate EW training while protecting civil aviation, but only if those activities follow hard, harmonized procedures. ICAO should convert the current mix of advisories and national practice into a concise instrument that mandates advance publication, measurable operational limits, real time monitoring, emergency cease authority, and reporting. This approach preserves operational readiness for defence forces while keeping the safety of every civilian flight as the top priority. The templates and examples already exist in national notices and exercises. What is missing is global standardization and a requirement that every EW exercise that has the potential to affect civil aviation be planned and executed to those standards.