Rules of the Air — Page 115, Lesson 181

Let’s pick this up right where the clearance procedure gets practical. I want to walk you through what happens when that ATC clearance is actually passed to you before departure, because this is where the discipline of air law meets real cockpit behaviour. First, the normal practice: an ATC clearance is passed to the aircraft prior to departure. At busy aerodromes, they don’t want this tying up the tower frequency, so a discrete clearance delivery frequency is established. Its RT call sign is “DELIVERY.” That leaves the other tower frequencies free for the purpose they were intended for — actual control of traffic. Now, here’s a subtle point: the person reading the clearance to you will, in all probability, not be the ATCO issuing the clearance. So the voice on the radio is a relay, not the controller who actually made the decision. Keep that in mind. Before the reading begins, you will be asked if you are “Ready to copy?” That’s the standard prompt. Your response, when you are ready, should be “Go ahead.” Not “yes,” not “ready” — the phraseology is “Go ahead.” The clearance will then be read to you slowly, deliberately, so you have the opportunity to write it down. And it will be terminated with the words “read back.” That is your cue. Now the read-back requirement: you are required to read back the clearance exactly as you received it. Not approximately, not in your own words — exactly. If your read back is incorrect, the ATCO will read the entire clearance to you again, from the top, not just the part you got wrong. This will continue until you get it right. There is nothing unprofessional in asking for a repeat, or asking for a place name to be spelled. That is expected behaviour, not weakness. Here’s the legal teeth behind this. If you do not read it back correctly, and there is subsequently a board of enquiry into an accident, it will be stated that you did not understand the clearance as read to you, and you will be held responsible. That’s a direct personal liability. And one more warning: do not assume that air traffic controllers are infallible. If you think something is wrong — query it. The clearance is a contract between you and the controller; you are the last check in the chain. Now let’s move to section 6.37, clearances and route of flight. The route of flight shall be detailed in each clearance when deemed necessary. Two phrases you need to know precisely. First: “Cleared by flight planned route.” That means any route, or portion of a route, which is identical to that flight planned. So if your clearance matches your filed flight plan, that phrase authorises it. Second: “Cleared via (designation) departure.” That means a Standard Instrument Departure route — a SID — published in the AIP, the Aeronautical Information Publication. The designation in brackets is the specific SID identifier. So the distinction is clear: one phrase clears you along the flight-planned route, the other clears you via a published departure procedure. Both are precise legal authorisations, and your read-back must reflect exactly which one you received. That figure shows you the flight plan submission requirements — when a flight plan is to be submitted prior to operating. It’s the context for why the clearance references the flight-planned route in the first place.