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Daylight Savings

Daylight Savings

On October 4th, Australian Eastern Daylight Savings Time (AEDT) begins, with clocks going forward by one hour at 2AM.

This will result in Victoria being 11 hours ahead of UTC (UTC+11), rather than 10 hours (UTC+10) as it is now. This has implications for flying training at TVSA. It is important to remember the difference between local time and UTC when planning flights for several reasons.

Daylight Available

Those of you who have completed the CPL Navigation theory subject may remember the pain of converting between Universal Coordinated Time (UTC), Australian Eastern Standard Time (AEST), and Australian Eastern Daylight Savings Time (AEDT). Depending on your planned route, your daylight available could be more or less than expected. Let’s have a look at a simple example using Bacchus Marsh:

YBSS 3/10/20

First Light – 021928 UTC = 030528 AEST

Last Light – 030854 UTC = 031854 AEST

YBSS 4/10/20

First Light – 031926 UTC = 040526 AEST / 040626 AEDT

Last Light – 040855 UTC = 041855 AEST / 041955 AEDT

We can see from the above conversions for First Light and Last Light at YBSS that if we were to forget the change on the 4th to UTC+11, we might be expecting to be able to depart in daylight an hour earlier than we actually could, or not use the daylight to our full advantage, and accidentally plan to return home an hour earlier than we needed to.

This becomes slightly more complicated when crossing borders into states/countries that are in different time zones. Queensland, whilst on the same time zone as Victoria for most of the year, does not recognize daylight savings time, and as such remains on AEST or UTC+10.

Departure Time

More obvious is the difference when submitting a flight plan on NAIPS. As flight plans are submitted in UTC, it is important to remember the change in the conversion. A simple example of this is as follows:

On 3rd October, you plan to leave on a flight at 11:30AM. This is equal to 01:30UTC, as the difference is 10hrs. On 4th October, the clocks have gone forward one hour, and now the difference to UTC is 11 hours. If you had submitted your departure time as 01:30UTC, this would now convert to 12:30AEDT.

A simple mistake if you are unaware of the change, but it can have implications on the availability of services or clearances if ATC are not expecting you for another hour. The NAIPS website has a UTC clock at the top of the page to help with conversions, and computer clocks (including smartphones) will usually adjust their clocks automatically to suit. These tools can help you avoid entering the wrong time in your flight plan.


A similar issue occurs when considering SARTIME. Whilst this is a bigger problem when the clocks go backwards at the start of the year, the clocks going forward can also present an issue. Let’s say you submit a SARTIME of 0500 UTC, expecting that to convert to 1500 AEST. In actual fact, it converts to 1600 AEDT. If the worst was to happen and you had to conduct a forced landing, your SARTIME would expire an hour after you expected it to, which may delay search and rescue services.

If we reverse this and consider the clocks going backwards an hour at the start of the year, we can see that SARTIMEs nominated under the assumption of an 11 hour difference would actually expire an hour earlier than expected. This results in lots of expired SARTIMEs countrywide and it is an expensive drain on the resources of AUSSAR.

A Safety Notice will be posted to FSM to ensure that you are reminded of the time difference when you log in for the first time after daylight savings commences. If you have any questions about the impact of daylight savings on flying training, please see your instructor, or the Safety Manager, Daniel Hadler.