Airways — Page 153, Lesson 148

I want to walk you through the start of the Airways chapter. This is where we set up the tools and definitions you'll need for the navigation and flight planning part of your examination. First, a practical point about the materials. For the exam, you will need Jeppesen's "Student Pilot Route Manual for Part-Flight Crew Licensing" or an equivalent approved publication. I want to be very clear about something: the selected Jeppesen charts in that manual are not current and are not to be used for actual navigation. They are training aids only. The manual contains more charts than you will usually need for the examinations, so don't be overwhelmed by the volume. Now, let's look at what you will be expected to do in the exam. This gives you the syllabus for this part of your study. You will need to: - Select routes, and decode and explain the meaning of the symbols, from en route charts, area charts, departure and arrival charts, and airfield charts. - Extract, from those charts, tracks, distances, heights or altitudes, magnetic variation, and the frequencies and call signs of navigation facilities. - Compute heading, ground speed, and elapsed time. - Select the correct flight level or levels for your track direction and for obstacle clearance. - Complete a part of a Navigation Plan or Navigation Log. - Identify airspace classifications and restricted areas. - Extract Instrument Approach Minima at your destination and at your alternate aerodrome. You will provide the manual yourself for the examinations. That means during the exam you may use the legend printed in the manual. However, because the allotted time for answering the questions is limited, you must be familiar with the ABBREVIATIONS, the CHART GLOSSARY, and the most commonly used symbols from the CHART LEGENDS — all of which are included in the INTRODUCTION to the manual. Do not rely on looking everything up from scratch; you need to know these cold. Let's move into the Jeppesen Manual, or JM, Chart Glossary. The glossary provides unique ICAO definitions that are commonly used in Jeppesen publications. FAA — that's United States Federal Aviation Administration — terms are included when they differ from the ICAO definition. It is strongly recommended that these definitions, particularly the ICAO ones, are carefully studied and committed to memory. Here are the specific ICAO definitions you need to note from this excerpt. First, AERODROME ELEVATION. This is defined as the elevation of the highest point of the landing area. So it's not the elevation of the runway threshold or the apron; it's the highest point on the actual landing surface itself. Second, ALTITUDE. This is the vertical distance of a level, a point, or an object considered as a point, measured from mean sea level. So altitude is always referenced to sea level. Third, DECISION ALTITUDE (DA) or DECISION HEIGHT (DH). This is a specified altitude or height in a precision approach at which a missed approach must be initiated if the required visual reference to continue the approach has not been established. There is a critical distinction here: DA is referenced to mean sea level, while DH is referenced to the threshold elevation. So DA is an altitude, DH is a height above the runway threshold. Fourth, ELEVATION. This is the vertical distance of a point or a level, on or affixed to the surface of the earth, measured from mean sea level. So elevation is a specific type of vertical measurement — it applies to features on the ground, not to an aircraft in flight. These definitions are foundational. You will use them constantly when reading charts and planning approaches.