Phonetic Alphabet, Numbers, and Time: ROC-A Radio Basics
Phonetic Alphabet, Numbers, and Time: ROC-A Radio Basics
ROC-A candidates often ask what to study first. A good place to start is the foundation: phonetic alphabet, numbers, and time. These three areas appear simple, but they are essential for clear aeronautical radio communication.
Quick links: Free ROC-A Study Hub • Free ROC-A Quiz • Book ROC-A
Quick answer
ROC-A candidates should practise the phonetic alphabet, number transmission, and 24-hour time until they can use them naturally. These basics reduce confusion when spelling call signs, transmitting frequencies, reading times, or confirming instructions.
Why these basics matter
RIC-21 says the ITU phonetic alphabet is used to avoid confusion when transmitting difficult or unusual words, isolated letters, groups of letters, or communication in difficult conditions.
RIC-21 also includes transmission of numbers, time and date, procedural words, call signs, and calling procedure as part of ROC-A operating procedures.
Phonetic alphabet
The phonetic alphabet helps prevent confusion between similar-sounding letters. For example, B, D, E, G, P, T, V, and Z can be confused on a noisy frequency if spoken casually.
Practise spelling:
C-GABC = Charlie Golf Alpha Bravo Charlie
Numbers
Numbers are used for:
- aircraft identifiers
- altitudes
- headings
- transponder codes
- frequencies
- runway numbers
- times
- weather information
Practise slowly and clearly. Accuracy matters more than speed.
Time
RIC-21 says the 24-hour clock should be used during radiocommunications, with time expressed using four figures: the first two for the hour and the last two for minutes.
Examples:
0945 = zero nine four five
1345 = one three four five
2200 = two two zero zero
Connection to phraseology
NAV CANADA’s VFR and IFR Phraseology guides include phonetic alphabet, numbers, decimals, number groups, transponder phraseology, standard words, aircraft identification, and ATS unit expectations.
Sources: https://www.navcanada.ca/en/vfr-phraseology.pdf and https://www.navcanada.ca/en/ifr-phraseology.pdf
Suggested practice plan
Day 1: phonetic alphabet
Day 2: numbers and frequencies
Day 3: time and dates
Day 4: procedural words
Day 5: call signs and readbacks
Day 6: distress and urgency basics
Day 7: full ROC-A practice quiz
Where ROCALicence.com fits
ROCALicence.com provides a free study hub and quiz so candidates can prepare before booking the official ROC-A exam.
Helpful links
- Free ROC-A Study Hub: https://rocalicence.com/study-hub
- Free ROC-A Practice Quiz: https://rocalicence.com/quiz-1
- Book your ROC-A exam: https://rocalicence.com/roca
- ISED ROC-A overview: https://ised-isde.canada.ca/site/spectrum-management-telecommunications/en/licences-and-certificates/radio-authorizations/radio-operator-certification/restricted-operator-certificate-aeronautical-roc
- ISED RIC-21 ROC-A study guide: https://ised-isde.canada.ca/site/spectrum-management-telecommunications/en/licences-and-certificates/radiocom-information-circulars-ric/ric-21-study-guide-restricted-operator-certificate-aeronautical-qualification-roc
- Transport Canada phraseology overview: https://tc.canada.ca/en/aviation/publications/aviation-safety-letter/issue-4-2022/phraseology-guides
- NAV CANADA Operational Guides: https://www.navcanada.ca/en/aeronautical-information/operational-guides.aspx
Final takeaway
Do not skip the basics. The phonetic alphabet, numbers, and 24-hour time are the foundation of aviation radio communication and ROC-A exam preparation.
Start free: https://rocalicence.com/study-hub
Book ROC-A: https://rocalicence.com/roca
General educational information only. Always use official ROC-A study materials and current Canadian aviation references.
