Air Traffic Services — Page 286, Lesson 369

I want to walk you through the three stages of emergency in Air Traffic Services. This is a core piece of air law, and you need to know it cold, because it governs how air traffic control and rescue coordination centres react when an aircraft goes missing or gets into trouble. First, the umbrella term. All three stages together are known generically as the emergency phase. So when you hear "emergency phase," it's not one single thing — it's the collective name for three escalating stages of alert. Let's take them in order. Stage one: the Uncertainty phase. Its code word is INCERFA. This stage exists when one of two things happens. Either no communication has been received from an aircraft within a period of 30 minutes after a time at which normal communication should have been made — so if the aircraft was due to check in at, say, 10:00 and nothing comes by 10:30, that triggers it. Or, the aircraft fails to arrive at its destination within 30 minutes of the estimated arrival time. So the trigger here is essentially "we expected to hear from them or see them, and we haven't, within half an hour." Stage two: the Alert phase. Its code word is ALERFA. The alert phase is declared following the uncertainty phase — except when evidence exists that would allay apprehension as to the safety of the aircraft or its occupants. In other words, if you have good reason to believe everyone is fine, you don't escalate. But assuming you do escalate, the alert phase is declared when any one of four conditions is met. First: subsequent attempts to make communication have failed, and there is no further news of the aircraft. Second: the aircraft fails to land within 5 minutes after the issuing of a landing clearance. Third: information has been received that the operating efficiency of the aircraft is impaired — but note the qualifier — not that a forced landing is likely. So the aircraft is struggling, but it's not about to crash. Fourth: it is known that an aircraft has been subject to unlawful interference — that's your hijacking or similar situation. Stage three: the Distress phase. Its code word is DETRESFA. The distress phase is declared following the alert phase — except where there is reasonable certainty that the aircraft and its occupants are not threatened by grave and imminent danger. So again, if you're confident they're not in mortal danger, you don't escalate. But if you do, it's declared when any one of four conditions is met. First: further attempts at communication are unsuccessful, and widespread enquiries indicate the probability that the aircraft is in distress. Second: the fuel on board is considered to be exhausted. Third: information is received that the operating efficiency of the aircraft is impaired to the extent that a forced landing is likely — note this is the stronger version of the alert phase condition; here it's not just impaired, it's impaired enough that a forced landing is likely. Fourth: information is received that the aircraft is about to make, or has already made, a forced landing. So the logic of the whole system is escalation. You move from uncertainty, to alert, to distress, and each stage has its own code word — INCERFA, ALERFA, DETRESFA — and its own set of triggers. The key numbers to remember are the 30 minutes for the uncertainty phase, and the 5 minutes after landing clearance for the alert phase. And remember the qualifiers: the alert phase's impaired-efficiency condition explicitly excludes a likely forced landing, while the distress phase's version explicitly includes it. That contrast is exactly the kind of thing examiners love. Now, there's a figure I want to show you that ties into this emergency material — it's the ground/air signals from survivors, which is how people on the ground communicate with search aircraft during these very phases. Let me bring that up for you.