With the opening up of the on-board Internet by Lufthansa (see ON TOUR) a parallel can be drawn with the expansion of the railways 150 years ago. In those far off days there was no such thing as a common UK time. London worked on Greenwich but in the west Bristol was a few minutes behind. Frankly it did not matter.
Then came the Great Western Railway (The GWR ” God”s Wonderful Railway was the name that stuck). When a train left Paddington a telegraph was sent to the stations along the route confirming the time of departure, based on London/Greenwich time. The other railways copied. And so a British Isles standard time was created. Perhaps another first for Brunel. The United States were somewhat behind and it was not until 1883 that the confusion was eliminated and the four time zones introduced. Again it was the railways that led the campaign, Charles Dowd the highly focused advocate of the scheme.
Now with the Internet we have the same problem. Sitting in your Boeing 747 (or next year Airbus 340) it might be necessary to actually time a message or instruction. But what time do you use? That of your departure city or that of your destination? Or perhaps Greenwich, as do the people in the cockpit. UTC or Universal Time Coordinated) was defined in 1967, long before the public Internet was around. It is almost, but not quite GMT. There are some fairly technical explanations of why it is not GMT, but for the man on the Clapham Omnibus (to use an old fashioned phrase), it is effectively the same as GMT (unless he is a physicist or French). Internet connected computers are able to synchronise their clocks (within 50ms or so) with a "time server" with easily available free software, using the Network Time Protocol (NTP) or Simple Network Time Protocol (SNTP). There are estimated to be over 100,000 time servers on the internet. You can synchronise your computer with some of the most accurate atomic clocks on (or near) the planet, such as the one at Rugby, the US Naval Observatory, and in GPS satellites (which contain three clocks each). Plus of course the Greenwich Observatory itself.
ABTN would like to propose that in kitting out aircraft with Connexion by Boeing and other on-line Internet systems that airlines integrate into their software packs Greenwich Mean Time (GMT) and perhaps add (in brackets) GMT on timetables. Call it UTC if it upsets some sensibilities. A few milisecs will not matter. The onboard Internet is a quantum leap forward. It works and will become the norm in a few years hence. All it needs to do now is get it timed right.
http://tycho.usno.navy.mil http://greenwichmeantime.com