The B-21 Raider’s first flight on November 10, 2023 is a clear reminder that the next generation of strategic aviation will operate in a world where stealth and public surveillance collide. For pilots and controllers who work the National Airspace System every day, that collision is not hypothetical. It is an operational problem that must be managed without degrading safety for civil traffic.

ADS-B was designed to make that civil airspace safer. It broadcasts GPS-derived position, altitude, velocity and an aircraft identifier so controllers and properly equipped cockpits can see and avoid other traffic more reliably than with radar alone. The FAA mandated ADS-B Out for most U.S. airspace effective January 1, 2020 to support modernized surveillance and traffic separation.

That mandate, however, runs straight into a fundamental conflict for low observable military aircraft. The Department of Defense and other government users have operational security needs that can be compromised by continuous, public position broadcasts. The FAA recognized that tension in an interim final rule published in July 2019 that allows government aircraft to terminate ADS-B transmissions for sensitive missions and gives ATC the authority to direct non-transmission when transmissions would jeopardize ATC functions. In practice that gives DoD and other agencies discretion to turn cooperative broadcasts off when mission security or survivability requires it.

Meanwhile there is an uncomfortable reality: public, open-source flight tracking networks and aggregators collect and display transponder and ADS-B data in near real time. That capability has prompted Pentagon officials and defense commentators to call public trackers a risk to military operations because they make movements widely visible. That concern partly explains why the military retains the ability to disable ADS-B and other cooperative signals.

From a pilot and controller point of view the safety consequences are straightforward. Civil traffic depends on the predictability of cooperative surveillance. When a military aircraft operating at low observable settings moves through or near civilian corridors without ADS-B or a functioning transponder, traffic picture fidelity drops and workload for controllers and flight crews rises. If that happens in busy terminal areas or along Victor and Jet routes, the margin for error narrows.

How do test programs and the military mitigate the risk? The good operational practices I have seen and advised on are simple and pragmatic.

  • Keep operations in protected airspace when possible. Use restricted areas, military operating areas and test ranges. Those exist for a reason and moving a stealth flight into unconstrained civilian airspace increases risk.

  • Use robust ATC coordination and timely NOTAMing. When transmissions are off, the responsible test organization should coordinate with ARTCCs and tower facilities far in advance and issue NOTAMs that give civil operators situational awareness.

  • Employ chase aircraft, discrete call signs and procedural buffers for climb, descent and transition points. A chase plane or formation element with full cooperative equipment can provide a visible proxy for ATC and for flight-following services.

  • Use the FAA tools and authorizations that already exist. If an aircraft must deviate from ADS-B equipage requirements for a flight segment, there are procedures to request authorizations or to route around busy airspace. These tools are aimed at preserving safety while respecting operational needs.

  • Leverage non-cooperative sensors and multilateration when available. Ground radar, SSR, and MLAT solutions can and do fill gaps, but they are not a drop-in substitute for ADS-B in every environment. Controllers and pilots must plan for degraded surveillance scenarios accordingly.

Those measures work when both sides accept the operational tradeoffs. What worries me as a line pilot is when exceptions become routine without commensurate safety compensations. The FAA rule allowing exceptions anticipated they would not be used habitually. The practical test for the services and the FAA is whether exemptions are exercised in a way that preserves the safety and efficiency of the NAS while meeting mission requirements.

There are policy and technical avenues worth pursuing to reduce tension between stealth and safety. Policy first. The services should formalize transparent risk assessments and cross-organization agreements with FAA centers and local towers that spell out the safety mitigations whenever cooperative broadcasts are terminated. Those agreements should be reviewed publicly enough to satisfy safety stakeholders while preserving mission secrecy where genuinely required.

On the technical side, options worth exploring include secure selective broadcasting inside defined volumes, enhanced MLAT coverage where test activity is concentrated, and better integration of tactical test scheduling with civilian traffic flow management. None of these are magic bullets. They are incremental fixes that recognize we cannot trade away safety for security or vice versa.

Operational realism is the through line here. The B-21 is a capability that will operate in a crowded world. The people who fly and manage that world must keep solutions rooted in what actually happens in the cockpit and the control room. That means rigorous planning, conservative mitigations when cooperative surveillance is turned off, and a willingness from both the military and the FAA to harden processes that protect both mission security and the flying public.