English or German on aviation radio: language rules, BZF and AZF

If you hear aviation radio for the first time in a video from Frankfurt, you might expect German – and get fast, heavily abbreviated English. In a recording from the glider field next door, on the other hand, it sounds like “Segelflugzeug im Gegenanflug” (glider on downwind). Both are correct. Whether English or German is spoken on aviation radio follows clear rules that depend on the ground station, the flight rules and the crew’s radio certificate. This guide explains the international requirements, the German BZF and AZF certificates, the language endorsement in the license and why English of all languages became the common language of aviation.

English or German: the short answer

On aviation radio, you may in principle use English or the language the ground station normally speaks. At stations serving international traffic, English must always be available on request. Which languages a station offers is published in the Aeronautical Information Publication (AIP) of the country concerned.

In Germany, there is also a practical split: VFR (visual flight rules) may be handled in German, while IFR (instrument flight rules) is handled in English as a rule – the difference between the two sets of flight rules is explained in the article VFR and IFR. Because airline flights are almost always flown under instrument flight rules, you mostly hear English at a commercial airport and often German at small airfields with private, glider and ultralight traffic. Which language a crew may use is ultimately determined by their radio certificate – together with the language endorsement in the license.

Why English is the language of aviation

An aircraft crosses several countries in a few hours. If every control station spoke only its own language, crews on a flight from Frankfurt to Lisbon would have to master German, French, Spanish and Portuguese. The International Civil Aviation Organization (ICAO) therefore recommended as early as the early 1950s, in Annex 10 to the Chicago Convention, using English for international radiotelephony. At first it was only a recommendation, but it caught on worldwide.

That does not mean every pilot and every controller spoke fluent English. Only in the early 2000s did ICAO tighten the requirements and introduce binding Language Proficiency Requirements: anyone who uses the radio internationally must demonstrate a defined language level. Accidents in which misunderstandings on the radio played a role were also a trigger – more on that below.

An important point: radio English is not everyday English. The core is standard phraseology, a fixed vocabulary with fixed sentence patterns. “Cleared to land”, “hold short”, “line up and wait” – every phrase has exactly one meaning. How this language is built is explained in the article Radio phraseology. Letters and numbers are pronounced according to a system of their own, which you will find in the article on the ICAO spelling alphabet.

The rules in Europe

In the EU, the Standardised European Rules of the Air, SERA for short, govern the language used on the radio. They take up the ICAO requirements and boil down to three principles:

• English or the national language: Radio traffic takes place in English or in the language the ground station normally uses.
• English on request: Ground stations serving airfields and routes of international air traffic must offer English at an aircraft’s request.
• Transparency: Which languages are available at a station is published in the AIP.

This explains the variety you hear in videos from different countries. Many states use the leeway mainly under VFR and with local crews. In recordings from France, Spain or Italy you therefore often hear the national language as soon as a domestic private pilot is on the frequency, and English as soon as an international crew joins in. One drawback of this mix: anyone who does not understand the national language loses part of the picture on the frequency – the so-called party-line principle, where everyone picks up what the others are doing, then works only to a limited extent.

Situation	Typical language in Germany	Why
Airline flight at major airports like Frankfurt or Munich	English	instrument flight, international crews
VFR flight at a controlled airfield	German or English	VFR allows German if certificate and ground station match
Uncontrolled airfield with a “Radio” station	mostly German	private, glider and ultralight traffic, often BZF II
Foreign crew under VFR	English	English must be available on request
Instrument flight, anywhere	English	IFR is handled in English as a rule in Germany

The table describes typical cases, not a binding list. Which languages an individual radio station offers is listed in the AIP – and at some small fields English is available only to a limited extent or by prior arrangement.

The German aviation radio certificates at a glance

Anyone who wants to use the radio in Germany needs an aviation radio certificate. The requirement goes back to international agreements; ICAO does allow the radio privilege to be integrated directly into the pilot license, as the US does, but Germany relies on separate certificates. They differ mainly by flight rules and language.

Certificate	Flight rules	Language	Scope
BZF II	VFR only	German only	Germany only
BZF I	VFR only	German and English	also abroad
BZF E	VFR only	English only	like BZF I, without the German part
AZF	VFR and IFR	German and English	worldwide
AZF E	VFR and IFR	English only	worldwide

BZF stands for Beschränkt gültiges Flugfunkzeugnis (restricted aviation radio certificate), AZF for Allgemeines Flugfunkzeugnis (general aviation radio certificate). The minimum age is 15 for the BZF and 18 for the AZF. The AZF generally requires a BZF and is mandatory for anyone aiming at an instrument rating or training as a commercial pilot – the costs and stages of that path are summarized in the article on ATPL training.

What happens in the exam

The BZF and AZF exams are run by the Bundesnetzagentur at its regional offices; an air traffic controller from DFS Deutsche Flugsicherung often sits in as an assessor. Alternatively, the BZF can be taken together with the theory exam for the pilot license at the Luftamt – the certificate is equivalent.

The BZF exam at the Bundesnetzagentur has a theory part with multiple-choice questions on procedures, aviation law and radio technology, practical questions on flight preparation and a simulated radio exchange in which the examiner plays air traffic control. For the BZF I, an English part is added: an aviation-related text is read aloud and translated orally, and in the practical part at least one procedure is played through in English. Phraseology, radio discipline, complete mandatory reports and short, clear transmissions are assessed. Distress and urgency calls can also come up – what they sound like is shown in the article Mayday and Pan-Pan.

The AZF examines the theory part in English and simulates an instrument flight, including a flight plan, in the practical part. Content and procedures may change; the current information from the Bundesnetzagentur is authoritative.

Language proficiency: the language endorsement in the license

A radio certificate alone is not enough to use English on the radio. In addition, ICAO requires proof of language skills, which is entered in the license as language proficiency. The scale has six levels, and six criteria are assessed:

• Pronunciation – understandable even to non-native speakers
• Structure – grammar and sentence construction
• Vocabulary – technical terms and general words
• Fluency – speaking pace and pauses
• Comprehension – even in unfamiliar situations
• Interaction – asking follow-up questions, confirming, resolving misunderstandings

The final result is always the lowest of the six sub-scores. Someone who reaches Level 6 in pronunciation but only Level 3 in comprehension has Level 3 – and may not use the radio internationally.

Level	Name	Validity
Level 4	Operational	4 years, then re-examination
Level 5	Extended	6 years
Level 6	Expert	indefinite

Level 4 is the minimum for international radio traffic. Interestingly, native speakers can also cause problems on the radio if they speak too fast, slip in slang or deviate from phraseology. Good radio communication is therefore less a question of mother tongue than of discipline. In Germany, language exams are administered only by bodies recognized by the Luftfahrt-Bundesamt (the German Federal Aviation Office). For operators of air sports equipment, special rules apply to the language proof in Germany, though usually not abroad – if you want to cross the border in an ultralight, you should clarify this beforehand.

When language becomes a safety risk

The stricter language rules have a serious background. Several major accidents show how quickly misunderstandings on the radio become dangerous:

• Tenerife 1977: In the collision of two Boeing 747s at Los Rodeos airport, 583 people died. Ambiguous wording around the takeoff contributed to the disaster. In the aftermath, phraseology was sharpened, and the word “take-off” has since been reserved for the actual takeoff clearance. The background is explained in the article on the Tenerife disaster of 1977.
• Avianca Flight 52 (1990): The crew of a Boeing 707 on approach to New York did not report their critical fuel situation using the unambiguous emergency wording. The aircraft crashed after running out of fuel, and 73 people died.
• Charkhi Dadri (1996): In the collision of two aircraft near Delhi, 349 people died. Language and communication problems are considered one of the factors.

These cases are the reason phraseology and language proof are handled so strictly today. Clear standard phrases leave little room for interpretation – no matter which mother tongue is spoken on either side of the frequency.

German on the radio: how it sounds

German radiotelephony follows the same logic as English, just with German standard phrases. Clearances such as “Start frei” (cleared for takeoff) or “Landung frei” (cleared to land) are fixed terms, and altitudes are also given in feet and speeds in knots in German. Registrations are spelled with the ICAO alphabet, so “Delta Echo Alpha Bravo Charlie” – in German radio too.

The radio stations differ by call sign: controlled airfields identify themselves as “Turm” (tower) or “Tower”, and at uncontrolled airfields the ground radio station in Germany is called “Radio”. Which station is responsible for what is explained in the article Delivery, ground, tower, approach, center. And where the small airfields with German radio traffic are located is shown in the guide Finding small airfields on maps.

A special case is the aviation radio permit (Flugfunkerlaubnis) for air sports equipment such as ultralight aircraft: a simplified national privilege that is tied to the license and may only be used in certain airspaces. If you get into flying via the ultralight license, you will find the details in the article on the ultralight license. For glider pilots, the article on the glider license (SPL) is worth a look, and for powered-aircraft pilots the one on the private pilot license PPL(A). Which airspaces play a role here is explained in Airspace C, D, E and G.

What this means for you as a spotter

For spotters, the language topic has mainly a practical side: it helps you make sense of radio recordings you listen to legally – in documentaries, in learning material or in web streams from countries where that is allowed. In Germany, listening to aviation radio without authorization is not legally covered, and passing on what you heard is prohibited. Before you get into scanners or apps, be sure to read the article Listening to aviation radio: technology and legal situation; what it looks like abroad is described in Listening to aviation radio online.

A few patterns help when listening:

• Call signs instead of airline names: Airline flights identify themselves with the airline’s radio call sign plus flight number. At Lufthansa, the call sign is identical to the name; at other airlines it differs significantly. Background on codes and call signs is in the article on IATA and ICAO codes.
• A language switch as a clue: If a ground station in videos from abroad suddenly switches to the national language, a local VFR pilot is usually on the frequency.
• Brevity is deliberate: Radio traffic does without pleasantries. What sounds curt is simply efficient.

Anyone who really wants to understand the radio and use it themselves takes the proper route via a radio certificate. Getting started without pilot ambitions is rather rare, but many spotters eventually end up in the cockpit themselves out of their passion for flying – or in the tower, as the article Becoming an air traffic controller shows.

What to keep in mind

• Radio certificate and language endorsement belong together. The BZF I allows English only if the language proficiency is also validly entered.
• Level 4 expires. If you only have Level 4, you must be re-examined after four years – otherwise you lack the privilege for English on the radio.
• Check the AIP. Not every small radio station offers English without restriction. When in doubt, the AIP clarifies which languages are available.
• Phraseology beats feel for the language. Anyone who radios cleanly in standard phrases is understood – even with an accent.
• Listening in is not a right. A radio certificate is not permission to listen in on the radio at the fence or to publish recordings.

Conclusion

English is the common language of aviation, but not the only one. The international rules allow, besides English, the national language of the ground station, as long as English remains available for international crews. In Germany, IFR flying is handled in English as a rule, while German is possible under VFR. Which language a crew may use is determined by their radio certificate – BZF II, BZF I or AZF – and the language endorsement in the license. For you as a spotter, that explains why the major airport sounds English and the glider field sounds German.