Single-engine Class B - Climb — Page 308, Lesson 386

Let’s pick up right where the take-off rules left off and move into the climb. For a single-engine Class B aeroplane, the climb performance requirements come from EU-OPS, but the practical numbers and rules you’ll actually use are in CAP 698, section 2, page 6. At the top of that page, under point 3.1, you’ll find a statement that might surprise you: there are no obstacle clearance limits and no minimum acceptable climb gradients for this class of aeroplane. Let me break that down, because it’s a big deal and it’s easy to misunderstand. First, the obstacle clearance part. For most other classes of aeroplane, the regulations require the pilot to demonstrate that the aircraft can clear any obstacle within the take-off flight path by a set margin — typically 50 feet or 35 feet. That’s a hard, enforceable safety margin. But for a single-engine Class B aeroplane, there is no regulatory requirement to demonstrate obstacle clearance at all. That sounds like a loophole, doesn’t it? Surely the whole point of regulations is to enforce a safety margin. Here’s the key reasoning: the pilot of a single-engine Class B aeroplane must, at all times, have visual contact with the ground. Because you always have the ground in sight, you can always see any obstacle in the take-off path, and you can therefore avoid it. The regulation assumes that visual avoidance is your safety margin, not a calculated clearance. That said, the book makes a very practical point: if you know there are obstacles in the take-off flight path, it may be prudent to carry out an obstacle clearance calculation anyway, even though the law doesn’t force you to. Now the second part: there is no minimum acceptable climb gradient for a single-engine Class B aeroplane. Again, that seems to fly in the face of the idea that operational regulations exist to enforce safety margins. But the reason is that the climb performance isn’t governed by the operational rules — it’s governed by the certification specifications for this type of aeroplane. The certification standards, not the operational rules, are what set the climb performance bar for this class. So the takeaway here is a contrast you need to hold clearly: for most aeroplanes, obstacle clearance and climb gradient are operational requirements with hard numbers. For a single-engine Class B, those operational requirements don’t exist — the safety margin comes from your continuous visual contact with the ground, and the climb performance itself is locked in at the certification stage, not the operational stage.