Approach Procedures — Page 185, Lesson 266

I want to walk you through the missed approach segment now — this is the part of the instrument approach that keeps you safe when the approach has to be abandoned. Let's start with the core rule. If you do not obtain the necessary visual criteria at decision altitude or height — that's DA/H — or at minimum descent altitude or height — MDA/H — or at any time during the instrument approach procedure you are unable to continue, the instrument procedure requires you to fly a missed approach. So the trigger is either a failure to meet the visual criteria at the published minimums, or any point where you simply cannot continue the approach. This procedure is always detailed on the instrument plate, together with the loss of RTF procedure — RTF is radio telephony, so the plate tells you what to do if you lose radio contact as well. The published information will always include a climb to at least MSA — that's minimum sector altitude. As soon as you elect to fly the missed approach, a climb to that altitude should be initiated. If the aircraft is already at that altitude, you maintain it. The climb gradient for the procedure is normally 2.5 percent. Now, the missed approach procedure consists of three phases: the initial missed approach, the intermediate missed approach, and the final missed approach. Let me take you through the initial phase first, because that's where the action starts. The initial missed approach begins at the missed approach point — the MAPt — and ends where the climb is established. This phase demands your full attention because you're establishing the climb and changing the aeroplane's configuration to get the aircraft away from the ground with increasing altitude. Because of that workload, guidance equipment cannot normally be fully utilized during these manoeuvres, and therefore no turns are specified in this phase. You fly straight ahead while you get the climb going. The missed approach is assumed to be initiated not lower than the DA/H in a precision approach, or at a specified point in a non-precision approach procedure, not lower than the MDA/H. So in a precision approach you initiate at or above the decision altitude or height; in a non-precision approach, at a specified point at or above the minimum descent altitude or height. Now, how is the MAPt defined? When the MAPt is defined by reference to a navigational facility or a fix — for instance the middle marker — the distance from the FAF to the MAPt is normally published as well. FAF is the final approach fix. That published distance may be used for timing to the MAPt. But here's an important annotation: in all cases where timing is not to be used, the procedure is to be annotated "timing not authorized for defining the MAPt." So if you see that annotation, you must not use timing to define the missed approach point. The MAPt may be defined in a procedure in several ways — and that's where we'll pick up next, looking at the specific ways the missed approach point can be defined.