When pilots and air traffic controllers speak to one another in the professional context, it usually takes place in prescribed, coded language, called ATC phraseology (also known as radiotelephony).
Crystal (1997) described registers such as “Seaspeak” for maritime use and limited phraseology for Air Traffic Control called “Airspeak”. Both of these abbreviated means of communicating have military roots linked to the limited radiotelephony employed for transmitting interactions. Much like military protocols, maritime and aviation phraseologies employ succinct, prescribed interactions in which all parties involved know the expected turn taking. Anticipated responses and read-backs help clarify directives and expedite procedures (Laird 2006).
Aviation English is not a natural language. Ragan (2002) refers to aviation English as “Airspeak” which he characterizes as “idiosyncratic, predictable, and yet problematic in communicating meaning.” Aviation communications consultant, Marsha Hunter conveyed:
…aviation phraseology doesn’t necessarily follow the linguistic rules we have hard-wired into our brains. One theory of human language postulates that verbs and nouns fall in certain places in sentences, and that all human languages follow the same basic rules. Aviation phraseology is a technical language concocted by humans, not a language which has evolved over millennia. Clearances don’t necessarily follow hard-wired linguistic rules, so we may have to think a few extra seconds to process what we’ve heard before we respond. We can learn to use invented technical languages, but it takes practice” (Hunter & O’Brien 2002).
Airspeak uses the standard English language as its basic structure but focuses solely on communicative needs in aviation. Standard English has been modified on many linguistic levels: phonetic, syntactic, morpho-syntactic and semantic in order to improve ATC flight communications and to ensure intelligibility of voice signals over radio links.
All the prescribed and predetermined expressions used in this context are self-contained and limited to the set sanctioned by the appropriate aviation authority. For example, The Air Traffic Controllers’ Handbook, 7110.65 (Air Traffic Control Services, The Federal Aviation Administration), contains extensive listings of words, phrases, and sentences to be spoken in a myriad of situations, e.g.:
- Runway two seven, cleared for take-off.
- Traffic, ten o’clock, one two miles, southeast bound, one thousand feet below you.”
“The phrases used in the radiotelephony context are designed to make the pilot/controller communication as concise and brief as possible, with the emphasis on accurate content as opposed to linguistic form. The brevity and conciseness of the communication is accomplished partly by using formulaic and predetermined sentence fragments” (Mitsutomi & O’Brien 2002: 6). For instance:
- American Airlines flight 54, turn left heading 100, intercept the localizer and proceed inbound, cleared for the ILS approach to 13 Right, maintain 2,200 until established. Contact tower on 120.6 at NOLLA.
In these examples you can note that the sentence fragments are usually simple imperative clauses: they do not have a subject, but a predicate in the form of imperative (i.e. the bare infinitive form of the verb). If the passive is needed, only the past participle is used, e.g. cleared for take-off; report established on the localizer. For instance:
- Fastair 345 cleared straight in ILS approach runway 28, descend to altitude 3000 feet QNH 1011, report established on the localizer.
There is an absence of grammar, complexity, words that are difficult to pronounce, words with ambiguous meanings, etc.; grammatical markers, such as determiners (the/a), pronouns, prepositions and auxiliary verbs are deleted. Unlike conversational English, aviation English is often disjunctive, without contracted forms and genitive constructions. Speech is broken up into units, often with a pause between them.
Aviation English is very dependent on context and a shared phraseology. ATC speech is often unintelligible to the outside listener because it is based on a lexicon of standard words and expressions, abbreviations and acronyms; even if the words can be understood, they do not make much sense without the knowledge of the air traffic control task.
Of the many factors involved in the process of communication, phraseology is perhaps the most important, because it enables pilots and controllers to communicate quickly and effectively despite differences in language, and reduces the opportunity for misunderstanding.
Besides mastery of the standard phraseology, pilots and controllers also need to acquire specific aviation vocabulary which Orr defines as “specific subsets of the English language that are required to carry out specific tasks for specific purposes.” ESP consists of vocabulary and concepts which are “unfamiliar to most native and nonnative speakers and thus require special training” (Orr 2002: 1).
In the following examples, common English words such as base, three o’clock, and clear have aviation-specific meanings.
- Turn base now, follow traffic at your three o’clock, cleared for the option.
- Remain clear of Class Charlie airspace, contact approach on one two three decimal six five.
The problem is that a good knowledge of phraseology, which is appropriate for exchanging expected routine messages, is not sufficient to deal with a non-routine situation when an unusual or an unexpected situation might cause confusion. A non-routine situation may also be an emergency situation, or have the potential to develop into an emergency situation. The only way that pilots and controllers can be sure to be able to communicate in a non-routine situation is if they both have a sufficient level of proficiency in the English language.
Plain English (or English used in non-routine situations) in pilot/controller communications needs to be clear, unambiguous, free of colloquialisms, idiomatic speech and slang. Below are two messages in plain English:
‘I have a flat tyre on the nose gear.’
‘We are having problems with the hydraulic systems.’