ATPL · Extra · Operational Procedures Atpl Ground Training… lesson — Page 138, Lesson 215

I want to walk you through the procedures for operating in the North Atlantic airspace, specifically the MNPSA — that stands for Minimum Navigation Performance Specification Airspace. This is a highly structured oceanic environment where standard radar separation doesn't exist, so every communication and clearance step is critical. Let's start with the Revised Estimate procedure. When you're crossing the North Atlantic, you'll be required to give position reports at specific waypoints. If your actual time over a waypoint differs from your estimated time by more than a certain tolerance — typically three minutes — you must issue a revised estimate. The format is plain language, free format, but the example given is: "Revised Estimate, Speedbird 212 on 3476, 57 North 040 West at 0305". That tells the controller your callsign, your current route identifier (3476 is a track identifier in the Organized Track System), your position at 57 degrees North, 40 degrees West, and the time you expect to be there — 0305 Zulu. Now, a key change happening in the NAT environment is the gradual introduction of data link communications for position reporting. On your first contact with the initial aeradio station — the first radio station you speak to as you enter the oceanic area — crews of participating aircraft should expect to receive the instruction: "VOICE POSITION REPORTS NOT REQUIRED". That means you stop making voice position reports over the radio; instead, you send them via data link, typically through CPDLC (Controller-Pilot Data Link Communications). This reduces frequency congestion. There's also a special rule for positions above 70 degrees North latitude. In that region, position reports are made at intervals of 20 degrees of longitude. So instead of reporting at every waypoint, you report every 20 degrees of longitude you cross. Now, let's talk about Radio Failure in the North Atlantic Area — this is a critical contingency. If you experience a radio failure prior to exiting the NAT region, the pilot shall maintain the last received and acknowledged oceanic clearance. That means you keep the level (altitude) and speed that were last confirmed by ATC, and you continue on that clearance to the last specified oceanic route point, which is normally landfall — the point where you first make landfall after crossing the ocean. After that point, what you do depends on your clearance type: - Cleared On Filed Flight Plan Route: If your oceanic clearance matched your filed flight plan route, you continue on that filed route. You maintain the last assigned oceanic level and speed all the way to landfall. After passing the last specified oceanic route point, you then conform to the relevant state procedures/regulations — that means the air traffic control rules of the country you're entering. - Cleared Other Than Filed Flight Plan Route: If your oceanic clearance gave you a different route than what you filed, after passing the last specified oceanic route point, you also conform to the relevant state procedures/regulations, but you must rejoin the filed flight plan route by proceeding via the published ATC route structure where possible, to the next significant point ahead as contained in your filed flight plan. So you don't just turn direct; you follow the published airways structure to get back on track. Finally, let's cover Initial Clearance. At least 40 minutes before entering the NAT airspace — and note that this applies above FL55 (Flight Level 55, which is 5,500 feet) — pilots are required to obtain an oceanic clearance directly from the initial OACC, which is the Oceanic Area Control Centre responsible for the entry point. The clearance request should include your requested flight level and your maximum acceptable flight level at the entry to the OCA (Oceanic Control Area). Because all the entry points to the OTS (Organized Track System) are within 250 nautical miles of the coast, the aircraft should be able to obtain this clearance by VHF radio — you don't need HF for the initial clearance. So to summarize: you request your oceanic clearance at least 40 minutes out via VHF, you report position by voice or data link as instructed, you issue revised estimates when your timing changes, and you have a clear procedure to follow if your radio fails.