Pilotage and dead reckoning: Difference between revisions

* Higher altitude: Less dead reckoning required, more pilotage possible.

Pilotage or map reading is, in fair weather and at a bit higher [[altitude]], nearly independent of dead reckoning.  The two main uses for the map is to catch any sings if drift before you have drifted to far off track and to accurately find and turn at the checkpoints.  In order to effectively use the map it is usually prepared with checkpoints, tracks, minute marks and various annotations.  This can be done in many ways from very simple to all the way to extremely detailed.

One very important thing to keep in mind is that you might not have all that much time in the cockpit to read the map.  In essence the things drawn on the map ''must be unambiguous'' and be possible to read ''on a glance''.

Usually, the first step in planning is part of the map preparation.  That is finding suitable checkpoints, marking them and plotting tracks between the checkpoints.  The tracks might involve turn arcs, preferably after the checkpoints, shifting the tracks to the side altering the course of the leg to the next checkpoint.  The size of the turn arcs, if the are drawn at all, are depending on the scale of the chart, the turn angle, and the performance of the aircraft.  While a double decker may turn on a dime a jet fighter at high speed might have a turn radius of several miles, which significantly shifts its course to the next checkpoint.

Other annotations can include the new course, heading, altitude, air speed, radio frequencies, the required fuel to get back, to the next checkpoint or to a divert, alternative or emergence airfield, etc.

While this is not the best place to go into map legends, there is a few things that are important to mention.

While reading the map it is easy to get into the bad habit of trying to figure out where you ''currently'' are.  This will result in that you mentally might be a few miles behind the aircraft, which can be hazardous in some circumstances.

# Terrain

The larger landforms usually conforms well with the map.  The road networks in FlightGear are often detailed enough that one can use them as checkpoints and navigate between them.  Discerning between what is a road, a railway or a (small) river can be a bit of a problem hovewer.  Cities are not always in the same shapes as on the map. etc.

Using ''dead reckoning'' is more or less the act of following, and updating, a preplanned "time table", often called a ''([[VFR]]) navigation log'' or ''nav log''.  The difference between the nav log and your local bus' time table is that the nav log, apart from times and places, in this context often called ''checkpoints'' or ''waypoints'', also include the heading, [[altitude]] and [[airspeed]] you need to have to get to the next checkpoint on time.

One important thing to remember is that your planning never can get better than the weather forecast permits. In essence, if, or rather ''when'' the wind shifts, your calculations goes out the window and you have to rely more on your pilotage.

The navigation log, together with the map, is the principal tool in getting from point A to point B on time.  Most of the calculations done while planning, often done on scrap paper, goes right into the nav log.  Some of the numbers could also be drawn onto the map.

There's a few thing that complicates the calculations of the numbers in the nav log. To counter all these things some calculations are needed.  Often, at least at student pilot level, these are done with an E6-B or CR flight computer.