Right, let's pick this up — Page 308, Lesson 387

Right, let's pick this up. We've just established that for this class of aeroplane, there is no operational regulation mandating a minimum climb performance. The certification specifications in CS-23 are considered stringent enough on their own. But here's the crucial point I want you to take away: even without that regulatory requirement, it would be unsafe to operate the aeroplane with such poor climb performance that it can barely climb. So, as the pilot, you have a responsibility to know what climb performance the aeroplane will actually achieve. You need to be confident it will climb sufficiently for the conditions you're operating in. Now, how do you find that out? This is where the presentation of data comes in. Most pilot operating manuals, or aeroplane flight manuals, contain climb graphs. These graphs help you calculate the gradient of climb. For our purposes, there's a specific graph we use, and it's found in CAP 698, in section 2, page 7, figure 2.3. Before you even think about using any graph, you must be familiar with its associated conditions. Let's look at the conditions for this particular climb graph. The throttles are at maximum. The mixture is rich. The flaps and gear are up. And the cowl flaps are set as required. These are the fixed conditions for this graph. The climb speed is taken to be 100 knots indicated airspeed for all masses. So, regardless of the aeroplane's weight, the climb speed for this graph is 100 knots indicated. The graph itself has an example you can follow, using dashed black lines, so you can practise on your own. Graph accuracy is very important, so be as careful as possible when using them. Be especially careful when working out your true airspeed, which you'll need when you approach the right-hand side of the graph. You may need your navigation computer to do this, as it might not be given to you, as is the case in the example. So, to summarise: you use the climb graph to find the gradient of climb, you must respect the graph's conditions, and you need to be precise, especially with true airspeed calculations. That's the core of it.