On March 27, 1977, two Boeing 747s collided on the runway at Tenerife. Among contributing factors to the accident was the use of non-standard phrases in radio communication. This led to confusion about whether or not a clearance for take-off had been granted. In most circumstances, any misunderstanding would be quickly clarified, however on this day, there was dense fog. The tower controller couldn’t see either of the two planes, nor could the planes see one another. In addition, simultaneous radio transmissions meant that some messages were not heard. The use of ambiguous words made the already bad situation much worse. Clear communication is extremely important – and can be a matter of life or death – for pilots and air traffic controllers.
Pilots and controllers use standard phraseology to ensure that communication is clear and unambiguous. The sound quality in radiotelephony is variable, which increases the chance of miscommunication. The numbers ‘five’ and ‘nine’, for example, might easily be confused, so in standard phraseology, ‘nine’ becomes ‘niner’ and ‘five’ become ‘fife’. ‘Yes’, which might easily be lost in the hiss of radio interference becomes ‘affirm’, and ‘no’, which is a tiny word with huge importance becomes ‘negative’. There also are strict rules about read-back. To ensure that a message has been correctly transmitted and received, the recipient of the message repeats the information back to the sender. That way, any misunderstanding can be immediately corrected.
A busy international airport will handle an average of 1,500 plane movements per day. With so many pilots and controllers on the radio, messages need to be short and concise. Standard phraseology transmits essential information quickly and clearly. Every pilot and controller understands that a dangerous situation may arise at any point. Keeping the airwaves as open as possible contributes to air safety.
The International Civil Aviation Organization (ICAO), headquartered in Montreal, Canada, was formed in 1944 to ensure the safe and orderly development of international civilian aviation. ICAO sets global standards for pilots, airport authorities, and air traffic controls so that each flight is handled in the same way, using the safest procedures. ICAO’s work includes publishing guidelines on licensing, rules of the air, aeronautical charts, aircraft operation, transport of dangerous goods, and so on. It also publishes a Manual of Radiotelephony which details standard phraseology to be used throughout any routine flight.
English is the agreed language of civil aviation throughout the world. Air Traffic Control Officers (ATCOs) and pilots who are involved with international flights learn standard ICAO phraseology in English as part of their professional training. In many places tough, for example small, non-international airports, a local language is used on the radio because all of the controllers and pilots in the vicinity speak the language, and it feels more natural – and possibly safer – to use it. However, if pilots who do not speak the local language enter the airspace, then they may request that all of the radio communication be conducted in English so that everyone can understand the positions and movements of all of the aircraft in the area. However, this isn’t always the case, and it can be very frustrating, and possibly very dangerous, for pilots who don’t understand the local language.
When the weather is clear, the runways are in good condition, the planes are fully functioning, and the passengers and crew are healthy and well-behaved, standard phraseology works extremely well. But when things go wrong, it’s because something unexpected happens. By its nature, standard phraseology doesn’t include ways to describe non-routine events. In a recent episode involving flight Blaze 606, the pilot requested a priority landing because of a violent passenger on board the plane.
There is no standard phraseology to refer to a violent passenger, so the pilot had to do the best he can to communicate the message using plain English. The result is confusion about the intent of the transmission, which is resolved only when another controller – presumably one who speaks better English – takes over. From this experience, there is no standard phraseology for communicating about the details of this non-standard situation and possible resolutions and this is cause for concern by many.
ICAO recognises the importance of plain English in clear communication, especially in circumstances where standard phraseology is inadequate. In the past, it was considered adequate for pilots and controllers to demonstrate mastery of standard phraseology, but ICAO now requires a certain level of general English for all pilots and ATCOs (ICAO Operational Level 4, on page 2 of English for Aviation) to be fully licensed internationally.
Aviation English Academy teaches plain English in an aviation context as well as using standard phraseology. Our courses are fully based on ICAO guidelines and each course is specially designed to prepare students and professionals with the English requirements so that they can develop an exciting career in the world of international aviation.