[tz] Politics of TZ changes

[Paul Eggert]

On 05/13/2014 01:11 PM, Zoidsoft wrote:
> I wonder how they keep aircraft from landing on top of each other on 
> the runway when the skip forward or back?

The U.S. Federal Aviation Administration uses UTC for all operations.  
There is a stylized protocol for communicating times via voice radio, 
e.g., 19:20 UTC is transmitted as "won nin-er too ze-ro".  Controllers 
can also communicate local time upon request and this must be stated 
clearly, e.g., 18:30 local time might be transmitted "wun ait tree ze-ro 
local".  If there's any ambiguity about what "local" means, pilots and 
controllers are expected to be aware of and to handle it.

For more, see:

Federal Aviation Administration. Aeronautical Information Manual 
(2012-02-09, updated through 2013-08-22). Section 4-2-12 "Time". 
http://www.faa.gov/air_traffic/publications/atpubs/aim/aim0402.html