Indicator (IVSI) . . . . . . . . . . 75 — Page 663, Lesson 800

This is the index page of the book — the "V" and "W" entries. So what I want to walk you through here is how to read this index, because it's actually a map of the whole instrumentation syllabus. You'll see entries like "Vertical Speed Indicator (VSI)" pointing to page 73, "VSI Metering Unit" on page 74, and "Indicator (IVSI)" on page 75. The IVSI is the Instantaneous Vertical Speed Indicator — that's the instrument that gives you an immediate response to control inputs, unlike the basic VSI which lags. The index is telling you these are separate topics, each with its own page. Now, notice the pattern here. You have "Vertical Speed (V/S)" on page 370 — that's the general concept of rate of climb or descent. Then you have the specific instruments that measure it. The index distinguishes between the VSI, the VSI Metering Unit, and the IVSI. That's a clue: the metering unit is the internal mechanism, the calibrated leak that creates the lag, and the IVSI is the enhanced version with accelerometer compensation. Look at the speed limits listed here — VFE on page 44, VLE on page 45, VLO on page 45, VMO on page 90, VNE on page 44, VNO on page 44, Vs1 on page 44, Vso on page 44, VYSE on page 44. These are all airspeed limitations. VFE is flaps extended speed, VLE is landing gear extended speed, VLO is landing gear operating speed, VMO is maximum operating speed, VNE is never-exceed speed, VNO is normal operating speed, Vs1 is the stall speed in a specific configuration, Vso is the stall speed in landing configuration, and VYSE is the best rate-of-climb speed with one engine inoperative on a multi-engine aircraft. The index groups them all on page 44, which tells you that's where the airspeed limitations are consolidated. Then you have the navigation and communication entries. VHF on page 328, VHF Communications on page 317, Voice Communications on page 318 — VHF is Very High Frequency, the band used for air-to-ground voice. VOR on pages 286 and 288 is VHF Omnidirectional Range, the radio navigation aid. VOR Localizer tracking, abbreviated VOR LOC, is on page 369. VNAV on pages 271 and 274 is Vertical Navigation — that's the flight management function that computes a vertical profile. Now the display and memory entries. Visual Display Unit, also called Monitor, on page 308 — that's the screen. Volatile Memory on page 309 — that's memory that loses its contents when power is removed, which is why it's used for temporary data. VISUAL on page 319 is likely a flight phase or mode reference. Viscosity on page 122 — that's fluid thickness, relevant to instruments that use damping fluids. Then the warning systems. WARN on page 242, Warning annunciator on page 241, Warnings on page 433 — these are the alerting systems. Water Traps on page 17 — that's in the pitot-static system section, the drains that remove moisture from the pressure lines. Wander on page 144 — that's gyroscopic drift, the slow precession of a gyro. Finally, the flight management entries. Waypoint on page 293, Waypoint Positions on page 244 — those are the defined points in a flight plan. Weather Radar on pages 290 and 291 — that's the airborne radar for detecting precipitation. Weather Reports on page 323 — that's the meteorological information. So the whole point of this index page is to show you the structure. When you're studying, you use this to cross-reference. For example, if you're learning about the IVSI on page 75, you know the VSI metering unit on page 74 is the foundation, and the basic VSI on page 73 is where it starts. The index is your navigation tool through the entire book.