Starting with P — Page 573, Lesson 575

This is the index of your General Navigation manual — the alphabetical list of every topic in the book, with the page number where each one starts. I want to walk you through the entries that fall under the letters P, Q, R, and S, because these are the terms you'll be tested on, and I want to make sure you recognize each one before we dive into the chapters. Starting with P. Pressure Altitude is on page 88 — that's the altitude indicated when your altimeter is set to the standard pressure setting of 1013.25 hectopascals. It's the height above the standard datum plane, not necessarily your true height above the ground. Pressure (or Position) Error is on page 105 — that's the error in your airspeed and altimeter readings caused by the way air flows around the static port, the position of the sensor on the aircraft. These two are closely linked, and you'll see them again when we study instrument errors. Moving to Q. QDM is on page 478 — that's the magnetic bearing you'd need to fly to reach a station, the heading to the beacon. QDR is also on page 478 — that's the magnetic bearing from the station to your aircraft, the radial you're on. QTE is on page 478 as well — that's the true bearing from the station to your position, measured from true north instead of magnetic north. These three Q-codes are the standard radio navigation bearings, and you must keep them straight: QDM is to the station, QDR is from the station in magnetic, QTE is from the station in true. Quadrantal Directions is on page 4 — that's the system of naming directions by the quadrant they fall into, like northeast, southeast, southwest, northwest, rather than by degrees. Now R. Rate of Descent is on page 212 — that's the vertical speed at which your aircraft descends, usually expressed in feet per minute. Real Variation Map is on page 48 — that's a chart that shows the actual magnetic variation across the Earth's surface, the lines of equal variation called isogonals. Reciprocal Directions is on page 6 — that's the opposite direction, exactly 180 degrees from your heading. Rectified Airspeed (RAS) is on page 105 — that's your calibrated airspeed corrected for position error, the speed you get after you've removed the pressure error I mentioned earlier. Relative Bearing is on page 481 — that's the angle measured clockwise from the nose of your aircraft to a station or object, not from north. Resolution Accuracy is on page 14 — that's the precision with which you can read a value from a chart or instrument, the smallest increment you can distinguish. Returning to Track is on page 199 — that's the procedure for getting back onto your planned route after you've drifted off it. Rhumb Line is on page 24 — that's a line on the Earth's surface that crosses all meridians at the same angle, a constant true bearing, which is the path you fly when you hold a steady heading. Finally S. Scale is on pages 223 and 275 — that's the ratio between a distance on the chart and the corresponding distance on the Earth's surface. Secant is on page 296 — that's a line that cuts through a surface, and in map projection terms it's the line where the projection surface intersects the Earth, giving you the standard parallels. Secular is on page 51 — that's the long-term, gradual change in magnetic variation over many years, as opposed to short-term changes. Sensitivity is on page 495 — that's how responsive an instrument is to a change in the quantity it measures. Sexagesimal System is on page 5 — that's the base-60 system we use for angles and time, where one degree has 60 minutes and one minute has 60 seconds. Sidereal Day is on page 384 — that's the time it takes the Earth to rotate once relative to the fixed stars, about 23 hours 56 minutes, which is different from a solar day. Small Circle is on page 8 — that's any circle on the Earth's surface that is not a great circle, so its plane does not pass through the Earth's center. Soft Iron Magnetism is on page 502 — that's the magnetism induced in soft iron components of the aircraft by the Earth's magnetic field, which changes with heading. Solar Activity is on page 51 — that's the sun's output that affects the Earth's magnetic field and can cause magnetic storms. Speed on a Glide Slope is on page 213 — that's the airspeed you maintain while flying down the instrument landing system glide slope. Spot Elevations is on page 221 — that's the exact height of a point marked on a chart, usually with a dot and a number. Standard Grid is on page 458 — that's a grid system superimposed on a chart for navigation, often used in polar regions. Standard Nautical Mile is on page 30 — that's the unit of distance equal to 1852 meters, based on one minute of latitude. Standard Parallels is on page 340 — that's the lines of latitude where the scale of a map projection is exact, where the projection surface touches the Earth. Standard Polar Grid is on page 466 — that's the grid system used specifically for navigation in polar areas, where meridians converge. And Standard Time is on page 401 — that's the local time adopted by a region, based on a standard meridian, usually a whole number of hours ahead of or behind UTC. That's the full sweep of P through S in your index. These are the terms you'll be meeting in the chapters, and now you know exactly where each one lives in the book.