Listening to aviation radio: technology and legal situation in Germany

Someone at the fence has a small radio at their ear and knows two minutes ahead which runway will be free next. The temptation is big: a scanner for the airband does not cost much, and with an SDR stick on a laptop it is even cheaper. But when it comes to listening to aviation radio, the legal situation in Germany is much tighter than what the technology allows. This guide explains how aviation radio works technically, what the law says about it, where the pitfalls for spotters are – and how you can still know completely legally what is happening at the airport.

Listening to aviation radio: the short answer

In Germany, you may buy, own and in principle also operate a receiver for the airband. What you may listen to with it, however, is governed by the eavesdropping ban in § 5 of the Telecommunications Digital Services Data Protection Act (TDDDG). According to it, you may only receive messages intended for yourself, for radio amateurs, for the general public or for an indeterminate group of people. According to the prevailing view, radiotelephony between the cockpit and air traffic control is not among them – it is aimed at the parties involved in air traffic and is subject to the secrecy of telecommunications. Without your own authorization, listening in at the spot is therefore not covered, and passing on what you heard is expressly prohibited.

How aviation radio works technically

To understand why scanners are so widespread, you need to know the technology. Civil aviation radiotelephony over land runs in the VHF band from 117.975 to 137 MHz. Unlike FM radio, it does not use frequency modulation but amplitude modulation (AM). That sounds rougher than FM but has a practical advantage: even with a weak, noisy signal, speech remains intelligible.

Communication is half-duplex: on a frequency, only one station transmits at a time while all others listen. That is why transmissions are so brief and standardized. Phraseology, call signs and readbacks make sure that even on a busy channel everyone knows who is meant. How call sign and flight number differ is explained in the article Callsign and flight number.

The 8.33 kHz spacing

Because the airspace over Europe kept getting busier, the channels eventually were no longer enough. Channels used to be 25 kHz apart; since the 1990s, Europe has been switching step by step to 8.33 kHz spacing, although in some areas the 25 kHz spacing is still in use. That fits roughly three times as many channels into the same band. Since November 2013, the Bundesnetzagentur has assigned new VHF frequencies only to radio stations with 8.33 kHz spacing. A quirk for tech fans: the channel number set in the cockpit is a kind of designation and does not in every case correspond exactly to the actual carrier frequency. Simple scanners that only know the old 25 kHz spacing struggle with such channels.

Which stations there are

At a large airport like Frankfurt or Munich, the tasks are spread across several stations: apron control and taxi traffic on the ground, the Tower for takeoffs and landings, and approach and departure control for the area around the airport. Added to this are automatic broadcasts like ATIS, which continuously transmit weather, active runways and air pressure on a frequency of their own and get a new identifying letter with every change. For emergencies, there is also the internationally reserved emergency frequency 121.5 MHz.

Which devices are used

Technically, the bar is low. You will come across three types of devices in spotter circles:

Device	How it works	Strengths	Weaknesses
Handheld scanner	Portable receiver with scanning across many bands	compact, battery-powered, ready to use right away	older models without 8.33 kHz spacing, often only a short antenna
Aviation handheld transceiver	Transmit and receive device made specifically for the airband	built for pilots, good reception	transmitting only with a certificate and assignment, legally doubly delicate for spotters
SDR stick on a computer	Software-defined receiver, demodulation by program	very cheap, flexible, also usable for ADS-B	needs a laptop or mini computer, an antenna and some getting started
World-band receiver with airband	Radio with an additional airband range	easy to use	mostly weak selectivity, little convenience

The SDR stick is interesting because many spotters own one anyway: the same hardware used to receive ADS-B position data on 1090 MHz technically also covers the airband. The difference lies not in the device but in what you receive. ADS-B signals are position reports that aircraft broadcast to everyone – more on this in Flight tracking with ADS-B for spotters and in the guide Building your own ADS-B receiver.

The legal situation in Germany

The eavesdropping ban in § 5 TDDDG

Until the end of 2021, the eavesdropping ban was in the Telecommunications Act, then it moved to the TTDSG, which is now called the TDDDG. In substance, the core has stayed the same. § 5 paragraph 1 allows you to use a radio device to listen to or otherwise take note of only those messages that are intended

• for you as the operator of the radio device,
• for radio amateurs,
• for the general public or
• for an indeterminate group of people.

Everything else is off limits. Broadcast radio and amateur radio expressly fall under the permitted categories. Aviation radio, on the other hand, is communication between air traffic control and aircraft operators. Holders of a radiotelephony certificate are obliged to preserve the secrecy of telecommunications, and relevant reference works expressly describe unauthorized listening to aviation radio in Germany as a criminal offense.

Passing it on is prohibited too

For spotters, almost more important is § 5 paragraph 2: you may not tell others the content of messages not intended for you and even the fact that you received them – and that applies even if the reception was unintentional. In practice, that means:

• no radio audio track under your landing video,
• no livestream from the fence with the tower running along,
• no “The controller just said …” in the group chat or in the story.

If you shoot videos, it is better to record the real engine sound – tips on this are in the article Shooting plane spotting videos.

What you risk

§ 27 TDDDG makes both violations punishable: prohibited eavesdropping (no. 1) and prohibited disclosure (no. 2). The penalty range extends to two years of imprisonment or a fine. Only intentional acts are punishable. How strictly it is prosecuted in an individual case is another matter – but nobody would want to rely on “Everybody does it” in court.

What is not prohibited

Owning a scanner or SDR stick is allowed. The only exception is devices disguised as everyday objects and thereby particularly suited to secret eavesdropping – § 8 TDDDG prohibits those even to own. A normal handheld scanner does not fall under that.

A gray area for ATIS?

The question keeps coming up whether automatic broadcasts like ATIS are intended “for an indeterminate group of people”. There is no binding clearance for that, and the answer depends on interpretation. For spotting practice, the question is fortunately almost irrelevant: the weather information that ATIS contains, you can get completely legally through public weather reports. How to read METAR and TAF is explained in the article Reading METAR and TAF.

And Austria, Switzerland, streaming portals?

Austria and Switzerland have their own telecommunications laws with their own rules – check for yourself what applies before a spotting trip there. International portals that stream aviation radio live generally offer no feeds for German frequencies. For listening to foreign streams, too, the rule is that redistributing and recording for your own publications is not a good idea.

The legal route: your own radiotelephony certificate

Anyone who really wants to understand and use the radio cannot get around a radiotelephony certificate. In Germany, there are several levels:

Certificate	Language	Used for	Note
BZF II	German	VFR within Germany	entry point for many private pilots
BZF I	German and English	VFR, also internationally	includes English technical texts
AZF	German and English	additionally instrument flight	requires BZF I or II
BZF E / AZF E	English only	equivalent to BZF I and AZF respectively	variant without the German exam part

The BZF and AZF exams are run by the Bundesnetzagentur at its regional offices; alternatively, the BZF can also be taken together with the theory exam for the pilot license at the aviation authority (Luftamt). The certificate is not an admission ticket for listening in at the fence, though: it entitles you to take part in aviation radio in the course of flight operations and obliges you to confidentiality. If you are toying with the idea of moving into the cockpit yourself, you will find the training routes in the article Becoming a pilot.

How to know what is happening even without radio

The good news: almost everything spotters want to get from the radio is also available legally – often even more clearly.

At official visitor areas you also pick up a lot without pressing a button: at the Munich Airport visitors’ hill, at the Zeppelinheim viewing platform in Frankfurt or on the Düsseldorf observation deck you see taxiways and runways directly. If you stand there regularly, you soon read the traffic just as well as with radio in your ear: an Airbus A350-900 of Lufthansa taxiing to the runway, or a Boeing 747-8 turning onto final approach, announce themselves even without the tower.

What to keep in mind

• Separate the device from its use. The fact that a scanner is freely sold says nothing about what you may listen to with it. What matters is the message, not the hardware.
• Chance does not protect you from the ban on passing it on. Even what you heard unintentionally you may not tell others – this applies expressly under the law.
• Edit videos without radio audio. Especially with clips from abroad or from streaming portals, it is better to go with original sound from the spot.
• Stay honest during checks. If the police approach you at the fence, explain that you are photographing aircraft. What else applies around the operator’s house rules and restricted areas is summarized in Is plane spotting allowed?.
• Do not drive to the emergency. If you discover an emergency code via a flight tracker, you keep access roads clear and stay at home – with or without radio.

Conclusion

Technically, listening to aviation radio is child’s play: AM in the VHF band between about 118 and 137 MHz, receivable with a handheld scanner or SDR stick. Legally, Germany sets tight limits. The eavesdropping ban in § 5 TDDDG allows only the reception of messages intended for you or for the general public, and according to the prevailing view, aviation radio is not among them. The ban on passing it on is even clearer: what you hear belongs neither in the video nor in the chat. The good news: with ADS-B, weather data and some experience at the spot, you know almost everything the radio would reveal anyway – and with a radiotelephony certificate, the legal path into radio operations is open to you.