Let's pick this up right where the correction tables left off — Page 408, Lesson 359

Let's pick this up right where the correction tables left off. We've been looking at how countries express their Standard Time as a correction to UTC, and I want you to notice something important: not every country uses a whole number of hours. Some use odd fractions, and that choice is entirely at that country's discretion — there's no international rule forcing them to use whole hours. Let me give you two concrete examples from the list. Chatham Island uses a correction of 12 hours 45 minutes. And the Tonga Islands use 13 hours. Now here's the fascinating part — those countries are actually in the Western hemisphere, yet they apply corrections that keep them on the same day as their neighbours in the Eastern hemisphere. That's a deliberate choice, and I'll come back to it shortly because it ties into the International Date Line discussion. Now, the book organises countries into lists, and I want you to understand what each list means. List 2 contains countries close to the Greenwich Meridian that normally keep UTC as their Standard Time. Note that this list includes Great Britain — so when you're working with UK times, you're essentially working with UTC itself. List 3 is different. These are countries generally to the west of Greenwich whose Standard Time is 'slow' on UTC — meaning their local time is less than UTC. The corrections given should be subtracted from UTC to give Standard Time, or added to Standard Time to give UTC. So if you have UTC and you want local time, you subtract the correction. If you have local time and you want UTC, you add it back. Now, some countries are subdivided internally, and you need to be aware of this because it affects which correction you use. Canada, for example, is divided by province. And even within some of those provinces — like the Northwest Territories — the correction is further subdivided by longitude. The USA is divided by states, with Alaska being sub-divided by longitude. Here's a practical tip for your exams: ATPL questions involving these areas will provide all the necessary detail, so you don't need to memorise every subdivision. Also, you do not need to use terms like 'Eastern Standard Time' — those aren't given in the Air Almanac, so stick to the corrections as listed. There is an anomaly in the USA listing for the Aleutian Islands, given as 10 hours, but I'll discuss that later — just be aware it exists for now. Finally, let's talk about Summer Time, or Daylight Saving Time (DST) as it's called in the USA. Some countries in all lists may carry Summer Time or DST in the summer months. This is normally indicated by an asterisk * against the country listed. And here's the key relationship: Summer time is normally 1 hour in advance of Standard Time. So if the Standard Time is, say, UTC minus 5, then during summer it becomes UTC minus 4 — one hour ahead of what it normally would be. That's the core of this section. The correction tables give you the baseline, and the asterisk tells you when to add that extra hour during summer months.