First, let's set the scene — Page 421, Lesson 514

I want to walk you through the detailed procedure for an increased V2 take-off. This is the step-by-step method you'll use with the CAP 698 graphs, and it's a classic exam favourite, so let's build it up carefully. First, let's set the scene. We're dealing with a situation where we want to improve our climb performance. The idea is that by using a faster V2 — that's the take-off safety speed, the speed at which we can climb after an engine failure — we get closer to VX, which is the best angle of climb speed. When V2 is faster and closer to VX, the climb performance significantly improves. And here's the payoff: because the climb is better, the climb limit mass can increase. That's the maximum mass allowed by climb requirements. When that goes up, the performance limited take-off mass goes up too, and that gives us an improved regulated take-off mass. So the whole chain is: faster V2, better climb, higher climb limit mass, higher performance limited take-off mass, better regulated take-off mass. Now, the procedure itself. CAP 698, section 4, page 28, has an introduction at the top that explains the concept very well — use that introduction in the exam if you're unsure what the procedure entails. Below that introduction is the detailed methodology, which is what we're about to go through. The graphs you need are on pages 29 and 30 of section 4 in CAP 698. The procedure is for an increased V2 take-off, and it uses two graphs side by side. Let me walk you through each step. Step (a): Select the set of graphs appropriate to the flap setting on the "improved climb performance field length limit" graph, which is CAP 698 Figure 4.15. So you pick the right graph set based on your flap setting. Step (b): Enter the relevant left-hand graph with the value of the field length limit mass minus the climb limit mass. So you take the field length limit mass, subtract the climb limit mass, and that's your input value. Travel vertically up to the normal 'climb limit' mass line. That's the line representing the normal climb limit mass. Step (c): From this intersection, move horizontally left to the vertical axis to read the climb mass improvement. And also move horizontally right to the vertical axis to read the increase to apply to V1. So one horizontal movement gives you two readings: left for climb mass improvement, right for the V1 increase. V1 is the decision speed, the speed at which you commit to take-off. Step (d): Continue horizontally right to the reference line of the right-hand graph. From this point, interpolate and follow the grid lines to reach a vertical input in the right-hand graph of the normal climb limit mass. So you're moving across to the right-hand graph, and you're using the normal climb limit mass as your vertical input there. Step (e): From this intersection, travel horizontally right to the vertical axis to read the increase to apply to VR and V2. VR is the rotation speed, the speed at which you rotate the aircraft for take-off, and V2 is the take-off safety speed we mentioned earlier. So this final step gives you the increases for both VR and V2. Let me just tie it all together. You start on the left graph with a mass difference, you read off a climb mass improvement and a V1 increase, then you carry across to the right graph using the normal climb limit mass as your vertical input, and you read off the VR and V2 increases. The whole procedure is designed to give you those speed increases and the climb mass improvement that flow from using a faster V2. I've got a figure here that shows the procedure visually — let me bring it up for you. And there's also a sample data figure for a runway with 2 mm contamination, which shows you what the actual graph inputs and outputs look like in practice. So that's the full procedure. The key things to remember are: you're using the field length limit mass minus the climb limit mass as your left-graph input, you read the climb mass improvement and V1 increase from the left graph, and you read the VR and V2 increases from the right graph using the normal climb limit mass as your vertical input.