Starting with FORTRAN — that's a programming language, and it appears on… — Page 657, Lesson 771

We're looking at the index of the book right now, which is a map of the entire syllabus. I want to walk you through the entries we have here, because each one is a technical term you'll need to know cold. Starting with FORTRAN — that's a programming language, and it appears on page 310. In the context of this book, it's likely tied to how certain flight management or navigation computers are programmed. You don't need to write it, but you need to recognize it as a legacy computer language used in aviation software. Next, FREE on page 219. That's a mode or state on a flight director or autopilot system — it means the system is not commanding any specific guidance, essentially disengaged from steering the aircraft. Freedom in Roll, page 172 — that's a concept in gyroscopic instruments. It refers to the number of axes in which a gyro is free to move, specifically the roll axis. A gyro with freedom in roll can tilt about that axis without being constrained. Free Text, page 324 — that's a data entry feature, likely on a flight management computer, where you can type in arbitrary text rather than selecting from a menu. Freezing Point, page 122 — that's the temperature at which a substance changes from liquid to solid. In instrumentation, this matters for things like fuel or hydraulic fluid behavior at altitude. Frequency Sweep, page 263 — that's a test or analysis technique where you vary the frequency of an input signal across a range to see how a system responds. It's used to characterize the dynamic behavior of instruments or control systems. Fringe Pattern, pages 256 and 257 — that's an optical phenomenon. When you see a fringe pattern, you're looking at interference bands of light, which are used in certain types of sensors or displays to measure very small displacements or angles. FROM/TO, page 241 — that's a VOR indicator. It tells you whether you're flying toward the station or away from it. The flag shows FROM when you're on the outbound side, TO when you're inbound. Fuel Control, page 398 — that's the system that regulates the flow of fuel to the engine to maintain the correct air-fuel ratio for the power setting. Fuel Metering Valve, abbreviated FMV, page 398 — that's the actual valve that physically adjusts the fuel flow based on commands from the fuel control unit. So the Fuel Control is the brain, the FMV is the muscle. Full ILS Mode, page 291 — that's the autopilot or flight director mode where the aircraft captures and tracks both the localizer and glide slope for a complete instrument landing system approach. Full Pitot/Static System, page 17 — that's the complete setup of pitot tubes and static ports that feed air pressure to your airspeed indicator, altimeter, and vertical speed indicator. "Full" means all the components are present and connected. Full VOR Mode, page 289 — that's the mode where the system uses the full VOR signal to determine bearing, as opposed to a degraded or backup mode. Function and Mode Keys, page 276 — those are the physical buttons on a control panel, like on a flight management computer, that let you select different functions or operating modes. Future Air Navigation Systems, abbreviated FANS, page 325 — that's the concept and set of standards for modern air traffic management using digital data link and satellite navigation to improve efficiency over older voice-based systems. FWS, pages 433 and 435 — that's an acronym, and in this context it stands for Flight Warning System. That's the system that monitors aircraft systems and alerts the crew to faults or abnormal conditions. Now moving to the G section. Gain Adaption, page 374 — that's when a control system automatically adjusts its gain, which is the ratio of output to input, based on current flight conditions to maintain stable handling. Gain Scheduling, page 417 — that's a more specific technique where the gain is varied according to a predetermined schedule, usually based on airspeed or altitude, to keep the aircraft's response consistent across the flight envelope. Gallons, page 2 — that's a unit of volume, used for fuel quantity. Simple, but you need to know whether you're dealing with US gallons or imperial gallons because the conversion matters. Gimbal Flip, page 146 — that's a gyroscope error where the gimbal, which is the ring that supports the gyro, suddenly flips to a different orientation, causing a momentary erroneous indication. Gimbal Friction, page 142 — that's the resistance in the bearings of the gimbals. It causes drift or precession errors in gyroscopic instruments because the gyro isn't perfectly free to move. Gimballing Errors, pages 156 and 157 — those are the collective errors introduced by the gimbal arrangement, including things like gimbal lock and gimbal flip, which distort the instrument's readings during certain maneuvers. Gimbal Lock, page 146 — that's the condition where two of the gyro's gimbals align, causing the gyro to lose a degree of freedom and tumble, giving erroneous indications. Gimbal Rings, page 234 — those are the physical rings that mount the gyro and allow it to rotate about its axes. They're the structural part of the gimbal system. Gimbals, pages 137 and 142 — that's the general term for the pivoted supports that allow a gyroscope to maintain its orientation in space regardless of the aircraft's attitude. Glide Slope Capture, page 381 — that's the moment when the autopilot or flight director acquires the glide slope signal and begins to track it downward toward the runway. Glide Slope Deviation, page 291 — that's the indication of how far the aircraft is above or below the correct glide path, shown on the instrument as a deflection. Global Air Traffic Management System, page 319 — that's the worldwide framework for managing air traffic, integrating communication, navigation, and surveillance to handle flights across international boundaries. And finally, Global Com — that's cut off, but it's clearly the start of "Global Communications," which would be the worldwide communication infrastructure used in aviation. Now, I want to point out something important. You'll notice many of these terms cluster around gyroscopes — Gimbals, Gimbal Lock, Gimbal Flip, Gimbal Friction, Gimballing Errors. That's a major topic in instrumentation, and these are the failure modes and errors you'll be tested on. When you see a gyro instrument, you need to know exactly how each of these errors manifests and what causes it. Also note the distinction between Gain Adaption and Gain Scheduling. Both adjust gain, but adaption is reactive to current conditions, while scheduling is a pre-planned function of a parameter like airspeed. That's a classic exam distinction. And the Fuel Control versus Fuel Metering Valve — one is the logic, the other is the actuator. Keep that separation clear in your mind. These index entries are your checklist. Every one of them is a topic you'll need to master. As we go through the book, we'll hit each of these in detail, but for now, you have the map.