We are starting Chapter 15, which is all about Visibility — Page 269, Lesson 252

We are starting Chapter 15, which is all about Visibility. This is a critical topic for you as a pilot because your ability to see and be seen directly affects the safety of every phase of flight, especially takeoff, approach, and landing. Let me walk you through the structure of what we are about to cover. First, the chapter opens with an Introduction on page 267. From there, we dive into the different types of fog, because fog is the most common and significant visibility reducer in aviation. We start with Radiation Fog, then Hill (Orographic) Fog, followed by Advection Fog. There is a section on Special Areas, then Steaming Fog (Arctic Smoke), Frontal Fog, Freezing Fog, and finally Ice Fog. Each of these has a distinct formation mechanism, and as a professional pilot, you need to know how and when each one develops so you can anticipate the conditions. After the fog types, the chapter moves to Visibility Reducers — that is, other phenomena that cut down your visibility, like haze, mist, dust, or precipitation. Then we get into the practical side: Visibility Measurement, Runway Visual Range (RVR), the Transmissometer, Instrumented Runway Visual Range (IRVR), and Forward Scatter Visibility Meters. These are the instruments and systems that give you the numbers you see on your weather report and ATIS. The chapter wraps up with a Summary of Visibility Effects, followed by Questions and Answers for self-testing. So, to give you the big picture right now: this chapter is going to teach you what causes poor visibility, how to identify each type of fog, and how we measure visibility precisely for flight operations. Let's begin with the first topic — Radiation Fog.