Air Traffic Services — Page 286, Lesson 371

Let's pick up right where the material leaves off — we're deep inside the Air Traffic Services chapter, and I want to walk you through the reporting and priority systems that tie the whole ATC picture together. First, let's finish the ADS picture. Basic ADS — Automatic Dependent Surveillance — transmits four core data items. Latitude, longitude, altitude, and time. And then a fifth one that's easy to gloss over but matters a lot: Figure of Merit, which is the accuracy of the position data. So when you see ADS data, you're not just getting a position — you're getting a statement of how trustworthy that position is. Now, 15.43 introduces the AIREP — that's an air-report. This is the formal channel for operational and meteorological information while you're en route. AIREPs come in two flavours: routine and special. Let's break down the routine report, because it has three distinct sections. Section 1 is the position report. Section 2 is operational information — specifically ETA and endurance. Section 3 is meteorological information. Now here's the key distinction in how these are triggered. Section 1 is mandatory — you always file it. Section 2 is transmitted when the operator requests it, or when you as pilot consider it necessary. Section 3 is transmitted when the aircraft has been specifically requested to make routine met reports at particular en route points. So the routine AIREP is not a fixed block — the mandatory core is the position, and the other two sections come in based on request or necessity. Now 15.44 — the AIREP SPECIAL. This is the special air-report, and it's triggered by encountering specific hazards. The list is precise, so let me give it to you exactly. Severe turbulence. Severe icing. Severe mountain wave. Thunderstorms without hail that are obscured, embedded, widespread, or in line-squalls. Heavy dust or sand storms. And volcanic ash cloud. Note the qualifier on the thunderstorms — it's not just any thunderstorm, it's the ones without hail that are obscured, embedded, widespread, or in line-squalls. That's the exact condition that triggers the special report. Now 15.45 — the Air Traffic Incident Report, or ATIR. This is the system for reporting, investigating, and getting feedback on incidents that happen while an aircraft is under ATC. The ATIR covers three categories. Aircraft proximity reports — that's AIRPROX. ATC procedure reports. And ATC equipment reports. Let me unpack the AIRPROX because it has a specific structure. AIRPROX reports can be originated by either the pilot — that's AIRPROX(P) — or by a controller — that's AIRPROX(C). And here's the procedural detail: from a pilot, the initial report is filed by RTF — that's radiotelephony — and then the report is completed on the ground. So the pilot starts it over the radio, but the full formal report gets finished once you're on the ground. Now 15.46 — priority. This is a fundamental rule. An aircraft known or believed to be in a state of emergency — and that includes being subject to unlawful interference — shall be given priority over other aircraft. So the moment you're in an emergency, or even believed to be, you get priority. That's not a request, it's a requirement placed on ATC. And finally 15.47 — change of callsign. ATC may require an aircraft to temporarily change its callsign. The trigger is specific: should there be a chance of confusion with another aircraft of a similar callsign on the same frequency. So it's a temporary measure to prevent confusion, not a permanent re-designation. Let me tie this together. You've got the ADS giving you the position data with accuracy. You've got the AIREP for routine and special reporting of operational and met conditions. You've got the ATIR system for incidents — with AIRPROX split between pilot and controller origin. And you've got the two operational rules: emergency priority, and callsign changes to avoid confusion. These are the reporting and priority mechanisms that keep the ATC system safe and accountable.