That’s an excellent question! The fact that helicopters often don’t appear on FlightRadar24 is a common source of confusion. The reason isn’t a single one, but a combination of factors related to technology, regulations, and user choice.
Here’s a breakdown of the main reasons:
1. The Primary Reason: Lack of ADS-B Out Transponder
FlightRadar24 and similar sites primarily use a network of ground-based receivers to pick up ADS-B Out signals. This is a modern, precise technology that broadcasts an aircraft’s GPS location, altitude, speed, and identity.
- Mandatory for most airplanes: In many controlled airspaces (like the US, Europe, Canada), ADS-B Out is now mandatory for most fixed-wing aircraft.
- Often optional for helicopters: Helicopters operating under Visual Flight Rules (VFR) at lower altitudes, especially for roles like news traffic, police, emergency medical services (HEMS), or private tours, are frequently not required by law to have ADS-B Out.
- Cost and Complexity: Installing ADS-B can be expensive and adds weight/complexity, which operators may avoid if not legally required.
If a helicopter isn’t equipped with ADS-B Out, FlightRadar24’s main network simply cannot “see” it.
2. Alternative Tracking Methods (When They Do Appup)
Sometimes you do see helicopters on FlightRadar24. This is usually because of one of these methods:
- MLAT (Multilateration): If an aircraft has a traditional Mode S transponder (but not ADS-B Out), FlightRadar24 can use a network of receivers