Rules of the Air — Page 118, Lesson 191

We're starting a new part of the Rules of the Air chapter now — the signals used when one aircraft intercepts another. This is a critical, high-stakes procedure, so I want you to think of it as a precise, non-verbal language. Every signal has an exact meaning, and there's no room for improvisation. The table we're looking at is split into two columns. On the left are the signals given by the intercepting aircraft — that's the one doing the intercepting. On the right are the responses from the intercepted aircraft — the one being intercepted. Each signal has a stated meaning, and each response has its own meaning. Let's start with the first intercepting signal. During the DAY, the intercepting aircraft rocks its wings from a position slightly above and ahead of, and normally to the left of, the intercepted aircraft. After the intercepted aircraft acknowledges, the interceptor makes a slow level turn, normally to the left, onto the desired heading. At NIGHT, the same procedure applies, but in addition, the interceptor flashes its navigational lights at irregular intervals. The meaning of this signal is: "You have been intercepted — follow me." Now, there are two important notes attached to this. Note 1 says that meteorological conditions or terrain may require the intercepting aircraft to take up a position slightly above and ahead of, and to the right of the intercepted aircraft, and to make the subsequent turn to the right. So the "normally to the left" is the standard, but weather or terrain can flip it to the right. Note 2 covers a speed mismatch. If the intercepted aircraft is not able to keep pace with the intercepting aircraft, the interceptor is expected to fly a series of racetrack patterns — that's an oval-shaped holding pattern — and to rock its wings each time it passes the intercepted aircraft. So the interceptor keeps circling back to maintain contact. Now, the response from the intercepted aircraft to that first signal. For AEROPLANES, during DAY or NIGHT, the response is rocking wings and following. At night, it also flashes navigational lights at irregular intervals. For HELICOPTERS, day or night, the response is rocking the aircraft, flashing navigational lights at irregular intervals, and following. The meaning of this response is: "Understood, will comply." There's a note here too: additional action required to be taken by the intercepted aircraft is prescribed in the RAC section — that's the Rules of the Air and Air Traffic Services section of the regulations. So this table gives you the core, but the RAC section has the extra detail. Next intercepting signal. DAY or NIGHT, the interceptor performs an abrupt breakaway manoeuvre from the intercepted aircraft. That consists of a climbing turn of 90 degrees or more, without crossing the line of flight of the intercepted aircraft. The meaning is: "You may proceed." So the interceptor is breaking off and clearing the way. The response to that, for AEROPLANES, day or night, is rocking wings. For HELICOPTERS, day or night, it's rocking the aircraft. Meaning: "Understood, will comply." Now the third intercepting signal. DAY — the interceptor circles the aerodrome, lowers its landing gear, and overflies the runway in the direction of landing. If the intercepted aircraft is a helicopter, the interceptor overflies the helicopter landing area instead. At NIGHT, the same applies, but in addition, the interceptor shows steady landing lights. The meaning is: "Land at this aerodrome." The response from the intercepted aircraft. For AEROPLANES, during the DAY, it lowers its landing gear, follows the intercepting aircraft, and — if after overflying the runway landing is considered safe — proceeds to land. At NIGHT, the same, plus showing steady landing lights, if carried. For HELICOPTERS, day or night, it follows the intercepting aircraft and proceeds to land, showing a steady landing light if carried. Meaning: "Understood, will comply." So the whole sequence is a dialogue. The interceptor says "follow me," you acknowledge and comply. The interceptor says "you may proceed," you acknowledge. The interceptor says "land here," you acknowledge and land. Each step is a confirmation, and the lights and wing-rocking are the vocabulary. That's the complete intercept signal set.