Discourse Analysis of Air Traffic Phraseology

Ondřej Čada

In my Bachelor’s thesis “Discourse Analysis of Air Traffic Phraseology” I examine so-called airspeak, a special variety of English for specific purposes. In contrast to Standard English, the language of aviation contains many distinctive differences in phonetics, a specialized lexicon and simplified grammar, and it is heavily dependent on knowledge shared by its users; all this makes it ideal discourse analysis material. As for the term itself, Cook claims that discourse analysis is a rapidly expanding field, which “examines how stretches of language, considered in their full textual, social, and psychological context, become meaningful and unified for their users.”

The aim of this thesis was therefore to examine and analyze the discourse of air traffic phraseology in the relevant linguistic areas. These were phonetics and phonology, lexicology, grammar and pragmatics. In order to conduct the analysis successfully, I created a corpus of  air traffic phraseology based on two hours of recordings at three different frequencies associated with Prague airport. In total, 451 utterances were transcribed.

On the level of phonetics and phonology, I mainly attempted to compare the phraseological pronunciation prescribed by ICAO to that of Standard English and then show its real usage in a Czech aviation environment. Probably the most interesting fact is that whereas pronouncing ‘three’ as /ˈtriː/ or ‘thousand’ as /ˈtaʊzənd/ would be generally frowned upon in regular English classes, it is the only correct way to pronounce these words when flying an airplane. This is mainly due to the possibility of confusion with other numbers, namely five and nine, which, unlikely as it may seem, do sound rather similar over the radio; hence they are pronounced /ˈfaɪf/ and /ˈnaɪnər/ respectively. Also, of course, the word spelling alphabet (Alfa for A, Bravo for B, etc.) is used for the reason shown in the example below (P = pilot, C = air traffic controller):

P: And departure good day, Transavia 5-2-3-6, passing 2 thousand 3 hundred /ˈtuː ˈtaʊzənd ˈtriː ˈhʌndrɪd/.

C: CSA 4 Lima Mike, descend 5 thousand /ˈfaɪf ˈtaʊzənd/ feet, QNH 1-0-1-2.

The second chapter focuses on analysis of the lexicon in terms of individual word classes and then explains the meanings of the so-called standard expressions found in the corpus. Interestingly, there are words that can’t be found in any standard dictionary, such as affirm, simply meaning “yes.” This was created by clipping the adjective ‘affirmative’ in the phrase “That is affirmative.” The correct pronunciation is /ˈeɪfɜː(r)m/ with the first syllable stressed. The reason is that over a poor-quality connection the full form could be mistaken for negative, which has exactly the opposite meaning.

C: Good evening sir, are you ready for departure?

P: Affirm, we’re ready for departure, Ryanair 8 Romeo Quebec.

Special attention was paid to abbreviations, since they are an inseparable part of the phraseology. In the corpus it was possible to find examples of clippings (localizer > loc), compound clippings (will comply > wilco), acronyms pronounced as words ATIS (Automatic Terminal Information Service), initialisms ILS (Instrument Landing System) and pseudo-acronyms, i.e. groups of letters that resemble acronyms (and are often pronounced as words) but do not stand for anything in particular, e.g. AKEVA, which is merely an arbitrary code given to one of the navigation points.

The third chapter in the practical part focuses on the use of grammar in the phraseology, especially from a syntactical point of view. In terms of sentence structure, the prevailing type is the simple sentence, since air traffic phraseology is a spoken only, simplified variety of English with an emphasis on conciseness, meaning that sentences longer than a few words are very rare and most radio exchanges contain only one instruction at a time. What is more, block language in the form of isolated noun phrases and frequent use of ellipsis make the language not dissimilar to newspaper headlines or train station announcements.

The last chapter examines the discourse at the level of pragmatics. Using examples from the corpus it shows the principles of taking turns when communicating in an air traffic environment and then explains the hidden meaning in some of the utterances, as in the following example, where an aircraft is descending towards its destination (Prague) and establishing initial contact with the controller at Prague Radar after it has been handed off by the Area Control Center (controlling the higher levels of the airspace).

P: Dobrý den, CSA 4 Lima Mike, passing 1-7-4 descending 1-4-0, Papa Romeo 7-4-2, Papa 1-0-1-2.

The pilot’s utterance, translated into “normal” language means: “This is a Czech Airlines aircraft, call sing CSA 4LM. We have been cleared by the previous controller to descend to 14,000 feet on standard pressure setting (1013,25 hPa) and our altimeter currently shows 17,400 feet. We are proceeding directly to waypoint PR742 on the standard arrival track and we are familiar with the current runway in use, transition level, weather and other relevant information. Barometric pressure at the airfield adjusted to sea level is 1012 hectopascals.”

To conclude, I believe that taken as a whole the thesis can aid understanding of how aviation phraseology is structured and how it works in comparison with everyday language, while providing an extensive overview of authentic spoken discourse used in the skies.