UTC / Zulu time
UTC (Coordinated Universal Time): standard time in Canadian aviation. Also called Zulu or Z (CAR 101.01(1); TC AIM GEN 1.5).
- Times usually in UTC.
- Local time allowed only when all operations are in one time zone (RIC-21 5.2).
Format (TC AIM GEN 1.5):
- Four digits (hhmm), 24-hour clock, no colon, trailing Z:
1500Z. - UTC given to nearest minute.
- Time checks given to nearest 15 seconds.
Midnight (RIC-21 5.2), same instant either way:
| Written | Meaning |
|---|---|
0000 |
Opens a day |
2400 |
Closes the day just ending |
Aviation day runs 0000 to 2359 UTC (TC AIM GEN 1.5):
- Calendar date changes at UTC midnight, not local midnight.
- Flight's UTC date can differ from local date.
Spoken: trailing Z read with its ITU phonetic-alphabet word (see phonetic-alphabet).
Trap: dropping the Z (bare time ambiguous: local or UTC); reading 2400 as start of next day instead of close of current one. (Zulu to local clock: see time-zones.)
References
- CAR 101.01(1) "UTC"
- TC AIM GEN 1.5
- RIC-21 5.2