How do people document their flights? I'm told I need to record the time at way points. On the map or on a separate piece of paper (with plog)? I've been taught to do it on map but as long as it's recorded instructor doesn't mind how.
Think of this: Why do you record your flights?
The CAA only requires a logbook entry, which is brakes off to brakes on plus details like the aircraft type, reg and callsign. Anything else is not required from a legal perspective. Nobody is going to care at what time you passed a certain waypoint, once the flight is over. Unless you busted controlled airspace or something like that.
Having said that, during the flight you will want to keep track of your progress. ATC might want to know the time you will arrive at a next waypoint (if under some kind of ATC service). You will want to arrive at your destination before the fuel runs out. And you will want to start looking for your next turning point a minute or two before reaching it. In other words: the time you pass a waypoint is important to you for the next leg of your flight.
So before the flight starts you calculate the ETE (estimated time en-route) for each leg. At the start of each leg you note (don't have to write this down, but is convenient) the ATA (actual time of arrival), and you add the ATA and the ETE together to get the ETA (estimated time of arrival) at the next waypoint. That is something you write down. You then set the course, power and everything as planned, and merrily fly along. Until about two minutes before the ETA, where you start looking for your turning point and the whole process repeats itself. And once you're over your turning point, it is very important to check the (actual) ATA against the (predicted) ETA.
This whole process has a few important purposes:
- It gives you the time when you need to start looking for a waypoint, and if you don't find your waypoint within a few minutes, you can initiate the 'unsure of position' procedures.
- It gives you a way of determining deviations from the plan - when the ATA and ETA are not the same. This can happen for instance because the aircraft is not performing as intended, or there is more headwind than forecast, or something else. And it allows you to update your plan while still in the air. Particularly if you're on a flight where fuel is marginal, where it allows you to decide to divert with sufficient fuel remaining.
So to summarize, it's not the recording of time per se that's important. What's important is to compare the estimated times in your plog to the actuals, and spot any deviations from your plan in time to do something about it.
Personally, I find it more convenient to use a dedicated plog for this, as my maps tend to have too much detail, and not enough white space, to write all these numbers down on the map. But that's also because I fly in Holland most of the time, which is very densely populated and has a very complicated airspace structure, so lots of stuff printed on the map already.