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OUT-N-BACK

OUT-N-BACK is a six-part video series, captured on multiple cameras, following VFR (Visual Flight Rules) flight in a Cessna 172. The 6000-kilometre round trip begins and ends in Bathurst, and captures some of the country’s most magnificent scenery and sights, including the Flinders Ranges, Lake Eyre in flood, the Furneaux Islands and Tasmania.

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One fact we know for sure – that sun is definitely going to set tonight.

The timing of last light is something you don't want to leave to guesswork. And just to confuse the issue, the AIP sets out a wordy definition: "Night" is that period between the end of evening civil twilight and the beginning of morning civil twilight. For all intents and purposes, first light should be construed as the beginning of civil twilight, and last light as the end of civil twilight. The terms "sunrise" and "sunset" have no relevance when calculating daylight operating times for the VFR pilot.

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It's a good idea to always know when last light will occur at your destination that day, even if you plan to be on the ground well before late afternoon. You may encounter stronger than forecast headwinds, or need to make a time-consuming diversion, or even an unplanned stop which may extend your ETA significantly.

Be ultra conservative when assessing the effects of last light. The time of last light will of course change considerably with the seasons, but have a think about local weather conditions which may impact on the available light, e.g. cloud cover, and think also about the surrounding landscape. Are you flying into an airstrip that is in the shadow of a hill or mountain? In fact, there is a special note in AIP 2.7 1.2 emphasising this point:

"... the parameters used in compiling (times of Last Light) ... do not include the nature of the terrain surrounding a location, or the presence of other than a cloudless sky and unlimited visibility at that location. Consequently, the presence of cloud cover, poor visibility or high terrain to the west of an aerodrome will cause daylight to end at a time earlier than (the time stated). Allowance should be made for these factors when planning a flight having an ETA near the end of daylight."

These days, we have a convenient method of identifying the time of last light. NAIPS automatically computes first light and last light for us. So you can note this down during your flight planning stage or otherwise request it via a telephone briefing or in-flight from Flightwatch.

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Whilst we're here, let's also talk about sneaking in just before sunset. In a nutshell, that's not a good thing to plan for! If you find yourself in this situation, at this time of day, the sun is going to be very low in the sky, perhaps even hovering just on the horizon. If you're landing into the west, this may mean you are looking directly into the sun on your final approach, making it almost impossible to see the runway.

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If there is absolutely nil wind, nor adverse slope or obstacles, nor traffic considerations, you could take the safer option of landing in the opposite direction, with the sun behind you. However, should this not be possible, and you find yourself confronted with a no-win situation, then how about considering doing another circuit or two? The sun will take only a few minutes to dip below the horizon, allowing you a window of decent light to get yourself down on the ground before last light.

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Remember: you need to have landed at least ten minutes before the published last light.

Reference:

AIP Gen 2.7 – 1

AIP Enr 1.2 1.1.2b