Aircraft Brakes — Page 149, Lesson 193

We're at the very end of the Aircraft Brakes chapter now, and I want to walk you through the last two items on the page — the brake temperature warning panel and the ECAM display — and then a concept called wing growth. After that, the chapter closes and we move into Flight Control Systems. First, the brake temperature warning panel. On a large transport aircraft, the brakes get extremely hot during landing and taxi, and the crew needs to know their temperature. That's what this panel is for. It gives the pilots a direct readout of brake temperature, and it's tied into the warning system so that if a brake exceeds its safe limit, the crew gets a caution or warning. Let me show you the panel itself — this is Figure 6.8. Now, on a modern Airbus, that same information is integrated into the ECAM — the Electronic Centralised Aircraft Monitor. The ECAM is the big screen in the cockpit that displays system parameters and warnings. Figure 6.9 shows a typical ECAM display, and you can see the brake temperature readout presented right there on the screen. So instead of a separate dedicated panel, the temperature data is centralised and shown on the ECAM, which is the modern way of presenting it. Now let's move to the last concept in this chapter: wing growth. This is a term that applies only to swept wing aircraft — that's the key qualifier. Here's the physics of it. On a modern big jet, the centre of the turning circle during a turn on the ground is not the inboard oleo — that's the shock absorber strut on the main landing gear — but a point further outboard. Because of that, and also because of the swept wing planform, the circle that the outboard wing tip describes is larger than is first apparent. In other words, when the aircraft turns, the wing tip sweeps through a bigger arc than you'd expect just by looking at the aircraft's geometry. That extra swept area is what we call wing growth. Let me show you Figure 6.10, where the wing growth area is shown in red. Wait — let me be precise. The wing growth illustration is Figure 6.10, and it shows the area in red. The point is that this may not be as great a problem on large aircraft that have body gear steering — that's steering on the main body gear, not just the nose gear — because those aircraft can turn more tightly and manage the swept area better. But the caution is clear: great caution should be exercised when manoeuvring large swept wing aircraft close to obstructions of any sort. The wing tip can swing into something you didn't think it would reach. So to summarise the whole chapter: we've covered the brake system, the temperature monitoring via the warning panel and the ECAM, and now wing growth as the final cautionary note about ground manoeuvring. That closes out Chapter 6 on Aircraft Brakes. Next up is Chapter 7, Flight Control Systems, which starts with an introduction and then moves into primary controls.