An approach when either part or all of an instrument approach procedure — Page 61, Lesson 95

I want to walk you through a set of definitions that are essential for understanding how we conduct approaches in professional aviation. These terms describe different types of approaches and the equipment we use to fly them. First, let's look at what happens when an instrument approach isn't fully completed. We have a specific term for that: it's an approach where either part or all of an instrument approach procedure is not completed, and the approach is executed with visual reference to the terrain. So if you start an instrument approach but have to break off the instrument portion early and continue looking out the window at the ground to land, that's what this describes. Now, let's talk about a specific technique called Continuous Descent Final Approach, or CDFA. This is a technique used for flying the final-approach segment of a non-precision instrument approach procedure. A non-precision approach is one that gives you lateral guidance but not vertical guidance — so you don't have a glideslope to follow. CDFA is a way to fly that final segment as a continuous descent, without any level-off. You start from an altitude or height at or above the Final Approach Fix altitude or height — that's the fix that marks the beginning of the final approach segment — and you descend all the way down to a point approximately 15 meters, which is 50 feet, above the landing runway threshold. Alternatively, if your aircraft type requires the flare manoeuvre to begin higher than 50 feet, you descend to that point instead. So the key idea is a smooth, uninterrupted descent all the way down to just above the runway, with no level segments in between. Next, we have the Stabilized Approach, abbreviated SAp. This is an approach that is flown in a controlled and appropriate manner in terms of three things: configuration, energy, and control of the flight path. Configuration means your flaps, landing gear, and speed brakes are set correctly for the phase of flight. Energy means your speed and thrust are managed properly. Control of the flight path means you're on the correct vertical and lateral path. This stabilized condition must be maintained from a pre-determined point or altitude/height all the way down to a point 50 feet above the threshold, or the point where the flare manoeuvre is initiated if that's higher. So if you're stable at 1,000 feet, you stay stable all the way down to 50 feet. Now, let's move to equipment. A Head-up Display, or HUD, is a display system that presents flight information into the pilot's forward external field of view. In other words, it projects data like airspeed, altitude, and flight path guidance onto a transparent screen in front of you, so you can see the information without looking down at your instruments. Importantly, it does not significantly restrict your external view — you can still see the runway and the outside world through it. Building on that, we have the Head-up Display Landing System, or HUDLS. This is the total airborne system that provides head-up guidance to the pilot during the approach and landing, and also during a go-around if needed. It includes all the components: all sensors, computers, power supplies, indications, and controls. A HUDLS is typically used for primary approach guidance down to decision heights of 50 feet. So below 50 feet, you'd be relying on visual reference to land. Let me recap those key numbers: CDFA takes you to approximately 15 meters or 50 feet above the threshold. The stabilized approach criteria apply down to 50 feet above the threshold or the flare initiation point. And a HUDLS provides guidance down to decision heights of 50 feet. That 50-foot figure is a recurring benchmark in these definitions.