Standard Phraseology

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Article Information
Category:	Air Ground Communication
Content source:	SKYbrary
Content control:	EUROCONTROL

Contents 1 Description 2 Effects 3 Typical Scenarios 4 Contributory Factors 5 Solutions 6 Related Articles 7 Further Reading

Description

Of the many factors involved in the process of communication, phraseology is perhaps the most important, because it enables us to communicate quickly and effectively despite differences in language and reduces the opportunity for misunderstanding.

Standard phraseology reduces the risk that a message will be misunderstood and aids the read-back/hear-back process so that any error is quickly detected. Ambiguous or non-standard phraseology is a frequent causal or contributory factor in aircraft accidents and incidents.

International standards of phraseology are laid down in ICAO Annex 10 Volume II Chapter 5 and in ICAO Doc 9432 - Manual of Radiotelephony. Many national authorities also publish radiotelephony manuals which amplify ICAO provisions, and in some cases modify them to suit local conditions.

Non-standard phraseology is sometimes adopted unilaterally by national or local air traffic services in an attempt to alleviate problems; however, standard phraseology minimises the potential for misunderstanding.

Effects

Failure to use standard phraseology can lead to misunderstanding and breakdown of the communication process.

Typical Scenarios

• The pilot of Rushair 1234 requests descent clearance as follows: “34, request FL120”. The ATCO mistakes the caller for Jetair 314 and responds: “314 descend FL120”. Rushair takes this clearance as intended for him and a level bust results.

• The ATCO transmits a clearance “Turn left heading 135 descend FL120 Maytree 235”. The pilot of Maytree 309 is expecting descent clearance, does not notice the wrong call sign and takes the clearance.

Contributory Factors

• Pilot workload;
• ATCO Workload;
• Frequency congestion;
• Expectation of clearance;
• Radio interference.

Solutions

• Improved training in standard phraseology for pilots and ATCOs.
• Insistence by managers and aircraft commanders on the use of standard phraseology.
• Obtaining confirmation or clarification whenever doubt exists as to the content or meaning of a message.

Related Articles

• Radio Discipline
• Non-Standard Phraseology
• Pilot-Controller Communications (OGHFA BN)

Further Reading

EUROCONTROL

• ALLCLEAR? Toolkit
• SAY AGAIN phraseology guide
• Communication Guide for General Aviation VFR Flights

AGC Safety Letters:

• AGC Safety Letter December 2004;
• AGC Safety Letter August 2005;
• AGC Safety Letter April 2006;

EUROCONTROL Action Plan for Air-Ground Communications Safety:

• AGC Briefing Note 5 - Radio Discipline.
• All Clear Phraseology Manual.

IATA

• Pilots & Air Traffic Controllers Phraseology Study. 2011. A joint project of IATA, IFALP, and IFATCA.