So the category is the driver, and the protection must match it — Page 447, Lesson 603

Right, let's pick this up with the level of protection for Rescue and Fire Fighting — RFF — at an aerodrome. This is where the category of the aerodrome actually dictates how much firefighting capability must be on standby. The core principle is that the level of protection provided must be appropriate to the aerodrome category. So the category is the driver, and the protection must match it. But there's an important exception, and it's tied to traffic volume. If the number of movements of the aeroplanes in the highest category normally using the aerodrome is less than 700 in the busiest consecutive three months, then — and this applies from 1 January 2000 — the level of protection may be not less than one category below the determined category. So you can drop down one category, but no further, and only under that low-traffic condition. Now, how is the aerodrome category itself determined? It's determined from the table, based on two things: the longest aeroplanes normally using the aerodrome, and their fuselage width. Let me walk you through the logic. You select the category appropriate to the longest aeroplane's overall length. But then there's a check: if that aeroplane's fuselage width is greater than the maximum width for that category, then you must use one category higher. So the fuselage width can force you up a category, even if the length alone would put you lower. That's a critical safety override. And there's a further rule for anticipated periods of reduced activity. During those times, the level of protection available must be no less than that needed for the highest category of aeroplane planned to use the aerodrome during that time — irrespective of the number of movements. So even if it's quiet, if a big aircraft is planned to come in, you must have the protection for that aircraft. The movement count doesn't let you off the hook during a planned period of reduced activity. Now let's look at the table itself, because you need to know the categories. Category 1 covers overall length from 0 metres up to but not including 9 metres, with a maximum fuselage width of 2 metres, and requires 1 rescue and fire fighting vehicle. Category 2 is 9 up to but not including 12 metres, still 2 metres maximum width, 1 vehicle. Category 3 is 12 up to but not including 18 metres, maximum width 3 metres, 1 vehicle. Category 4 is 18 up to but not including 24 metres, maximum width 4 metres, 1 vehicle. Category 5 is 24 up to but not including 28 metres, maximum width 4 metres, 1 vehicle. Category 6 is 28 up to but not including 39 metres, maximum width 5 metres, and now we go to 2 vehicles. Category 7 is 39 up to but not including 49 metres, maximum width 5 metres, 2 vehicles. Category 8 is 49 up to but not including 61 metres, maximum width 7 metres, 3 vehicles. Category 9 is 61 up to but not including 76 metres, maximum width 7 metres, 3 vehicles. And Category 10 is 76 up to but not including 90 metres, maximum width 8 metres, 3 vehicles. So you can see the pattern: the categories step up in length bands, each with a maximum fuselage width, and the number of rescue and fire fighting vehicles increases as the aircraft get bigger — from 1 vehicle in the smallest categories up to 3 vehicles for the largest. The fuselage width is the limiting factor that can bump you up a category, as I mentioned. That figure shows the marking of objects, which relates to the visual marking side of things. But for now, hold onto the key point: the category is set by the longest aircraft's length, checked against fuselage width, and the protection level must match — with the one-category reduction allowed only under the low-movement exception, and never during planned reduced activity.