Pattern A is the one closest to the runway — Page 405, Lesson 550

Let’s pick this up right where the runway holding point concept leaves off, because now we’re going to look at the actual markings that tell a pilot where that holding point is on the ground. There are exactly two distinct patterns for runway holding markings, and they are officially called Pattern A and Pattern B. You need to know both cold, because which one you see tells you something about the runway you’re holding short of. Pattern A is the one closest to the runway. In fact, the rule is that the closest holding point to a runway will always be marked with Pattern A. It’s positioned at the intersection of a taxiway and one of three runway types: a non-instrument (visual) runway, a non-precision approach runway, or a take-off runway. So if you’re holding short of a runway that has no instrument approach, or only a non-precision approach, or is used purely for take-off, the holding point right at that intersection is Pattern A. Now here’s the precision approach case. If there is a single taxi-holding position at an intersection with a precision approach category I, II, or III runway, that single marking must also be Pattern A. So even on the highest-category precision runways, if there’s only one holding position, it’s Pattern A. There’s also a distance rule for Pattern A on a code 4 runway — that’s the largest runway code, with a long runway length and wide wingspan. For a code 4 runway, the Pattern A holding point will be no closer than 75 metres to the centre line of the runway. So you’ll never see a Pattern A holding point closer than 75 metres from the runway centre line on a code 4 runway. And Pattern A is also called the visual holding point — that’s the one you use when you’re holding visually, not relying on instruments. Now Pattern B. This comes in when there are two or three taxi-holding positions at the same intersection. In that case, the marking closest to the runway is Pattern A, and the markings further from the runway are Pattern B. So Pattern B is always the one set back further from the runway. And any other holding point associated with a runway that’s required on a taxiway — not at that primary intersection — will also be Pattern B. So the logic is simple: Pattern A is always the closest to the runway, Pattern B is always further back. If you see Pattern B, you know there’s a Pattern A somewhere closer to the runway, and you’re holding at a point that’s set back further. Let me show you what these look like on the ground. Here’s Figure 20.10, which shows Pattern A runway holding markings — you’ll see the characteristic double solid line and double dashed line arrangement. And here’s Figure 20.11, showing Pattern B — notice the difference in the line pattern, which is how you distinguish them at a glance. Now, one more thing from earlier in the passage that ties this together. The location of a holding point on a precision approach runway is chosen so that a holding aircraft or vehicle will not interfere with the operation of radio navigation aids, specifically the ILS — the Instrument Landing System. That’s why the holding point is set back where it is: so your aircraft doesn’t block or distort the ILS signals that the approaching aircraft depends on. And a runway holding point may also be established where the approach to a runway passes over a taxiway to another runway — in that case, the associated sign will specify what the holding point is for, so you know exactly why you’re holding there. So to sum up the key points: Pattern A is always the closest holding point to the runway, used at visual, non-precision, and take-off runways, and at single holding positions on precision category I, II, or III runways. On a code 4 runway it’s no closer than 75 metres from the runway centre line, and it’s the visual holding point. Pattern B is used for the further holding positions when there are two or three, and for any other runway holding point on a taxiway. And the whole positioning logic on precision runways is to keep you clear of the ILS.