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?