Why does aviation use Zulu time instead of the local time? When reading aviation literature, it's common to find references to Zulu Time.


What is Zulu Time?
Why does aviation use Zulu Time instead of the local time?
Zulu means the letter Z in radio communication. The letter Z designates UTC time.

There is actually a list of time zones for each letter of the alphabet (except J):


Alpha time zone: UTC + 1
Bravo time zone: UTC + 2
...
India time zone: UTC + 9
Kilo time zone: UTC + 10
Lima time zone: UTC + 11
Mike time zone: UTC + 12
November time zone: UTC - 1
...
X-ray time zone: UTC - 11
Yankee time zone: UTC - 12
Zulu time zone: UTC + 0


However, the other time zones are seldom referenced in aviation.



Why do we use UTC time instead of local time?

Because flights often cross time zones.

Imagine this: the time now is 11:59. We will takeoff at 12:30 and fly west. Afterwards, at around 11:48, we will be 15 nautical miles away from the airport.....................Huh?

Even more confusing: We takeoff at 12:30 and land at 13:00 ==> we only need 30 minutes of fuel. Wrong! We actually cross a time zone and the actual flight time is 90 minutes. But we've taken off with 60 minutes less fuel than we need. What do we do?