We're looking at the index of the book — the "O" and "P" entries — Page 661, Lesson 785

We're looking at the index of the book — the "O" and "P" entries. This is a map of the whole course, so I want to walk you through what these terms mean and where they live in the syllabus, because each one is a concept you'll meet in full later. Let's start with the navigation and flight management entries. "Off Route Waypoints" at page 293 — these are waypoints you program into the flight management system that are not part of your active flight plan route. "OFFSET" at page 278 — that's a lateral offset, where you deliberately fly a parallel track a set distance to one side of your planned route, often for weather avoidance or noise abatement. Now the traffic and warning systems. "Off Scale Traffic Advisory" and "Other Traffic" both sit at page 485 — these are TCAS terms. "Other Traffic" is the lowest priority of traffic in the TCAS display, aircraft that pose no threat at all. "Off Scale Traffic Advisory" means a traffic advisory target that's outside the display range of your screen — the system still knows it's there, but it's beyond what the radar display can show you. Then we have the recording and data side. "On Demand" and "On Event" at page 326 — these are recording trigger modes for the flight data recorder or similar systems. "On Demand" means you record when someone actively requests it; "On Event" means the system records automatically when a specific trigger condition occurs, like an exceedance. "Optical Disk" at page 309 — that's a storage medium used for recording flight data or navigation database information. Now the gyroscopic instruments — this is a big family. "Outer Gimbal" at page 155 — in a gyroscope, the gimbals are the rings that mount the spinning rotor. The outer gimbal is the outermost ring that allows the gyro to move in one axis. "Pendulous Device" at page 228, "Pendulous (hanging) Vanes" and "Pendulous Vanes" at page 172, "Pendulously Suspended" at page 120, and "Pendulum" at page 187 — these all relate to how a gyro is made to seek the vertical. A pendulous vane is a vane that hangs like a pendulum; when the aircraft accelerates, the vanes deflect and create an erecting torque that precesses the gyro back to vertical. "Pendulously Suspended" describes a gyro that hangs from a point so gravity acts on it to keep it aligned. Now the control and performance systems. "Outer Loop Control" at page 363 and "Outer Loop systems" at page 354 — in autopilot or flight control terms, the outer loop is the higher-level control that manages the aircraft's overall path, like holding a heading or altitude, as opposed to the inner loop that stabilises the aircraft's attitude. "Operational Procedures" at page 275 — that's the section on how you actually operate the flight management system in day-to-day flying. Now the engine and instrument indications. "Over-read" at pages 127 and 132 — that's when an instrument reads higher than the true value, a form of instrument error. "Overspeed" at page 186 — exceeding the maximum allowable speed for the aircraft or a component. "Overspeed Warning" at page 441 — the alert that tells you you're approaching or exceeding that limit. Now the ground and gate logic. "On Ground" at page 321 and "Out of Gate" at page 321 — these are aircraft states used by the systems to decide what functions are available. "On Ground" means the weight-on-wheels or similar logic says the aircraft is on the ground; "Out of Gate" means you've left the gate but may still be on the ground. "O O O I" at page 321 — that's a shorthand for the aircraft states, likely "On Ground, Out, On, In" or similar — the exact expansion you'll see in that section. Now the physics and measurement. "Parallax" at page 8 — that's the apparent shift in position of an instrument needle when you view it from an angle rather than straight on; it causes reading errors. "Pascals" at page 42 — that's the SI unit of pressure, used in altimetry and airspeed measurement. "Parallel" at page 358 — that's a control mode where the autopilot or flight director operates in parallel with the pilot's inputs. Now the performance and passenger systems. "PERF INIT" at pages 273 and 274 — that's the "Performance Initialisation" page on the flight management computer, where you enter the data the system needs to calculate performance, like weights and cruise altitude. "Passenger Information" at page 323 — that's the cabin announcement or information system that keeps passengers informed. And "Overshooting" at page 16 — that's when the aircraft or a control system goes past its intended target, like overshooting a heading or an altitude during a manoeuvre. So the pattern here is: navigation and FMS entries, TCAS traffic categories, recording trigger modes, gyro erection devices, autopilot control loops, instrument errors, pressure units, and performance pages. Each of these will come back in full detail in its own chapter. For now, you've got the map — you know where everything lives.