Rules of the Air — Page 122, Lesson 193

I want to walk you through the signals that pass between an intercepted aircraft and the intercepting aircraft. This is one of those tables you'll be expected to know cold, because in a real interception the only way you communicate is through these visual signals — there's no radio chatter, no hand signals that work at those distances. So let's build it piece by piece. First, the big picture. The table has two sides. The left side is what the intercepted aircraft does — that's the aircraft being intercepted, the one that's been caught. The right side is what the intercepting aircraft does in response — that's the aircraft doing the intercepting. And each row pairs a signal from the intercepted aircraft with a meaning, and then the intercepting aircraft's response with its own meaning. Let's start with the first row, for aeroplanes — fixed-wing aircraft. Daytime signal: The intercepted aircraft raises its landing gear while passing over the landing runway at a height exceeding 300 metres — that's 1000 feet — but not exceeding 600 metres, which is 2000 feet, above the aerodrome level. And it continues to circle the aerodrome. So picture this: you're overhead the airfield, you raise the gear, you stay in the circuit. That signal means the aerodrome you have designated is inadequate. Night-time signal: Same height band — above 300 metres, not above 600 metres, above the aerodrome level — but instead of raising gear, you flash your landing lights while passing over the landing runway, and you keep circling. And there's a fallback: if you're unable to flash the landing lights, you flash any other lights available. Same meaning — the aerodrome you have designated is inadequate. Now, what does the intercepting aircraft do when it receives that? Two possibilities. If it's desired that the intercepted aircraft follow the intercepting aircraft to an alternate aerodrome, the intercepting aircraft raises its landing gear and uses the Series 1 signals prescribed for intercepting aircraft. The meaning of that response is "Understood, follow me." But if it's decided to release the intercepted aircraft, the intercepting aircraft uses the Series 2 signals prescribed for intercepting aircraft. That means "Understood, you may proceed." So right there you have two key terms — Series 1 signals and Series 2 signals. These are the standardised signal sets for intercepting aircraft, and the table is telling you which series to use depending on the intent. Series 1 means follow me; Series 2 means you're released. Now the second row. The intercepted aircraft — again, aeroplanes — does this day or night: it regularly switches on and off all available lights, but in such a manner as to be distinct from flashing lights. So it's a steady, regular on-off cycle, deliberately different from a flash. That signal means "Cannot comply." The intercepting aircraft's response to that is to use the Series 2 signals prescribed for intercepting aircraft, and the meaning is simply "Understood." Now the third row. The intercepted aircraft — aeroplanes — does this day or night: irregular flashing of all available lights. And for helicopters — rotorcraft — it's the same: day or night, irregular flashing of all available lights. That signal means the intercepted aircraft is in distress. And the intercepting aircraft's response to a distress signal is again the Series 2 signals prescribed for intercepting aircraft, meaning "Understood." So let me pull the pattern together, because that's where the real learning lives. The intercepted aircraft has three possible signals: the gear-up-and-circle or light-flash for an inadequate aerodrome, the regular on-off of all lights for cannot comply, and the irregular flashing for distress. The intercepting aircraft has essentially two responses: Series 1 signals meaning "follow me," and Series 2 signals meaning "understood" — and in the case of the inadequate aerodrome, Series 2 specifically means "you may proceed." Notice the contrast that matters operationally: regular switching on and off means cannot comply, while irregular flashing means distress. That distinction between regular and irregular is exactly what you must not confuse — one is a refusal, the other is an emergency. And one more thing worth flagging: the height band appears only in that first row — exceeding 300 metres but not exceeding 600 metres above aerodrome level. That's the window in which the gear raise or light flash is a valid signal. Outside that band, the same action wouldn't carry that meaning. That's the full table. The key takeaway for you as a pilot: if you're ever intercepted, these are the only signals you have to say "this aerodrome is inadequate," "I cannot comply," or "I am in distress" — and you read the intercepting aircraft's Series 1 or Series 2 response to know whether you're being led somewhere or released.