AI
Airband Radio: Unencrypted by Design
AM radio has been used for airband communications since before its 1947 specification. Two features make it suited for aviation and uniquely vulnerable. Heterodyning lets two simultaneous transmissions produce audible interference, signaling both parties to retransmit. A weak capture effect lets receivers hear distant planes well below the noise floor. Both features serve interoperability across 193 ICAO member countries. AM is unencrypted and receivable by anyone with a cheap radio or internet stream. A defunct tower transmitter costs under $200 on eBay and outputs 25 to 45 watts.
Voice Cloning a Controller in 10 Seconds
Voice cloning uses three steps: an encoder captures the unique characteristics of a target voice, a synthesizer applies that voice to input text, and a vocoder converts the resulting spectrogram into audio. Logan used ElevenLabs to build a clone from 10 seconds of controller audio, then generated a fake runway crossing clearance for a Speedbird heavy at JFK. ElevenLabs requires identity verification only for cloning celebrities or public figures, but has no guardrails for voices that sound like radio transmissions or ATC-formatted prompts.
How Runway Crossings Become Catastrophic
The 1977 Tenerife disaster began when separatists bombed Grand Canary Airport, diverting flights to single-runway Los Rodeos. A KLM crew misheard their takeoff clearance in thick fog, ignored a heterodyning signal from an aircraft still on the runway, and began takeoff. The resulting collision is the deadliest accident in aviation history. In 2024, JAL flight 516 struck a Japanese Coast Guard aircraft at Haneda. The coast guard crew believed they had takeoff clearance. An incursion alarm had sounded in the tower for over a minute. Stop bars on that runway were unserviceable.
What Mitigations Exist and Where They Fall Short
Stop bars are runway lighting that pilots must observe above any verbal clearance. The US has them at 26 airports with a target of 75 by 2026, a schedule already behind. Logan found in his research that stop bars are radio-controlled, adding another attack surface. TCAS is inactive below 1,000 feet, so it offers no protection during takeoff or landing. Enhanced flight vision systems including forward-facing cameras, infrared, and radar, common on cargo aircraft, would improve situational awareness. The long-term fix is LDACS, an encrypted L-band system in European trials, not expected in the US before 2030.
Notable Quotes
This talk is about my nightmare. Andrew “Helicopters of DC” Logan · ▶ 1:41
easy to create a convincing voice clone Andrew “Helicopters of DC” Logan · ▶ 18:39
22 right without delay. Andrew “Helicopters of DC” Logan · ▶ 18:20
So, there’s another problem. Andrew “Helicopters of DC” Logan · ▶ 21:21
Key Takeaways
- Air traffic control uses unencrypted AM radio that has not changed since before 1947.
- A voice clone trained on 10 seconds of audio can issue convincing fake runway clearances.
- Stop bars at runway crossings are the most practical safeguard but cover only 26 US airports.
About the Speaker(s)
Andrew “Helicopters of DC” Logan is an audio engineer, independent aviation journalist, and developer behind the HelicoptersofDC project. He previously presented Tracking Military Ghost Helicopters over Washington DC at Def Con 30. His advocacy urging lawmakers to review ADS-B exemptions for government aircraft has been cited by the Senate in the wake of the Flight 5342 crash.