Special Operational Procedures and Hazards — Page 160, Lesson 248

I want to walk you through two important topics from the Special Operational Procedures and Hazards chapter. First, we have a noise abatement take-off climb procedure, and then we'll look at the Constant Descent Final Approach, or CDFA, profile. Let's start with the noise abatement take-off climb. This is an example of a procedure designed to alleviate noise distant from the aerodrome, and it's specifically labelled as NADP 2 — Noise Abatement Departure Procedure number 2. The diagram shows a vertical profile of the aircraft after take-off. You'll see a height of 240 metres, which is 800 feet, marked on the left, and a height of 900 metres, which is 3000 feet, marked higher up. The procedure begins with take-off thrust, and the aircraft climbs at a speed of V2 plus 10 to 20 knots. V2 is the take-off safety speed, so you're climbing a little faster than that. The key instruction is: not before reaching 240 metres, or 800 feet, and while maintaining a positive rate of climb — meaning you are still climbing, not levelling off — you accelerate towards VZF. VZF is the zero-flap speed, the speed at which you can fly with the flaps fully retracted. At that point, you reduce power and begin the first flap or slat retraction. Alternatively, there is another option: you can wait until the flaps and slats are fully retracted, and while still maintaining a positive rate of climb, you then reduce power and climb at VZF plus 10 to 20 knots. So the procedure gives you two paths, but both involve delaying any power reduction or flap retraction until you are at least 800 feet and climbing positively, to keep the aircraft as quiet as possible for the community below. Now, let's move to the Constant Descent Final Approach, or CDFA, profile. This is a technique used for non-precision approaches — approaches that don't have a full Instrument Landing System, or ILS, glide slope. For commercial air transport aeroplanes operated by EU operators, these approaches should be flown using a CDFA profile. The purpose is to ensure that a Stabilized Approach can be conducted. Here's how it works: the aeroplane descends from the lowest holding altitude, abbreviated as LHA, in the arrival stack. The arrival stack is the pattern of aircraft holding at different altitudes waiting to land. From that LHA, the aircraft adopts a rate of descent of 300 feet per nautical mile. That's a specific descent gradient — 300 feet down for every nautical mile travelled forward — and this rate is maintained all the way down to the runway threshold. There is no interruption, no levelling off. This technique has several benefits. It minimizes power adjustments, because you're not constantly changing thrust to manage the descent. It also negates the need for the straight and level segment that would otherwise be required to intercept the glide path from below — in a traditional non-precision approach, you might level off briefly to capture the descent path, but with CDFA you don't. Additionally, it reduces fuel burn. While that might not be a major saving per single flight, when you multiply it by the annual total of approaches made across an entire operation, it amounts to a significant economy. That figure shows the CDFA profile graphically — a continuous descent from the holding altitude straight to the runway threshold. Now, the chapter then transitions into a new topic: Fire and Smoke. This is a major hazard area. The chapter outline lists several subsections: Fire in the Aeroplane, The Number and Location of Hand-held Fire Extinguishers, Smoke, Crew Protective Breathing Equipment (PBE), Crash Axes and Crowbars, and Overheated Brakes. We'll be covering each of these in detail as we go through the chapter.