Holding Side — Page 214, Lesson 288

Let’s start with the picture you’re looking at, because it gives us the geometry of the holding pattern. You have a fix, or facility, at the centre. The pattern is drawn as a racetrack. One side is the holding side, the other is the non-holding side. The inbound track is the leg you fly toward the fix, and the outbound track is the leg you fly away from the fix. The fix end is the end of the outbound leg nearest the fix, and the outbound end is the far end, where you turn back inbound. There’s also the abeam position, which is the point on the outbound leg where you’re directly level with the fix, at right angles to it. Now, the distance labelled ‘d’ on the diagram is the length of the outbound leg. In still air, that distance is 1 minute at 14,000 feet and below, and 1½ minutes above 14,000 feet. So the timing changes with altitude, and that’s a key point we’ll come back to. All turns in the pattern are made at rate 1, which is 3° per second, or at a bank angle of 25°, whichever requires the lesser bank. So you don’t just pick one; you use whichever gives the smaller bank angle. That’s the standard for holding. Now let’s go into the flying procedure in detail. When you fly the holding pattern, every turn is at that bank angle of 25° or rate 1, whichever is less. The procedures depict tracks, not headings. That means the published pattern is drawn as the path over the ground, and you as the pilot must maintain that track by making allowance for known wind. You apply corrections both to your heading and to your timing, during entry and while flying the pattern. Outbound timing begins over or abeam the fix, whichever occurs later. So if you pass over the fix first, you start timing then. If you reach the abeam position later, you start timing at that later point. If you can’t determine the abeam position at all, then you start the timing when the turn to outbound is completed. So there’s a clear fallback. The outbound track is flown for 1 minute at 14,000 feet and below, and 1½ minutes above 14,000 feet. That matches the ‘d’ on the diagram. But if the outbound leg is based on a DME distance, then the outbound leg terminates as soon as the limiting DME distance is attained. So instead of timing, you fly out to a specific DME range and then turn. If, for any reason, you’re unable to conform to the procedures for normal conditions, you must inform ATC as soon as possible. That’s a mandatory reporting requirement. Now the speeds. Holding patterns are flown at the speeds given in the table, Figure 10.2. Let me walk you through it level by level. Up to 4250 metres, which is 14,000 feet, inclusive, the normal conditions speed is 425 km/h, which is 230 knots. In turbulence conditions, it drops to 315 km/h, which is 170 knots. There’s also a note that 520 km/h, 280 knots, applies in turbulence for certain cases, and 315 km/h is for holdings limited to CAT A and B aircraft only. From above 4250 metres, 14,000 feet, up to 6100 metres, 20,000 feet, inclusive, the normal speed is 445 km/h, which is 240 knots. In turbulence, it’s 520 km/h, 280 knots, or Mach 0.8, whichever is less. From above 6100 metres, 20,000 feet, up to 10,350 metres, 34,000 feet, inclusive, the normal speed is 490 km/h, which is 265 knots. Above 10,350 metres, which is 34,000 feet, the speed is Mach 0.83, both in normal and turbulence conditions. Now the notes are important. Note 1 says the levels tabulated represent altitudes or corresponding flight levels, depending on the altimeter setting in use. So whether you treat them as altitudes or flight levels depends on your altimeter setting. Note 2: when the holding procedure is followed by the initial segment of an instrument approach procedure promulgated at a speed higher than 425 km/h, 230 knots, then the holding should also be promulgated at that higher speed wherever possible. So if the approach is faster, the holding can be faster too. Note 3: the speed of 520 km/h, 280 knots, or Mach 0.8, reserved for turbulence conditions, shall be used for holding only after prior clearance with ATC, unless the relevant publications indicate that the holding area can accommodate aircraft at these speeds. So you can’t just use that high turbulence speed on your own; you need ATC clearance first, unless the published documents say the area can handle it. Note 4: the 315 km/h, 170 knots, speed is for holdings limited to CAT A and B aircraft only. So that lower turbulence speed only applies if the holding is restricted to those aircraft categories. Note 5: wherever possible, 520 km/h, 280 knots, should be used for holding procedures associated with airway route structures. So on airway holdings, you’d prefer the higher speed. So the whole picture is: you have the racetrack geometry, the timing rules that change with altitude, the bank angle limit, the wind correction requirement, the DME alternative, the ATC notification duty, and the speed table with its altitude bands and turbulence conditions. That’s the complete holding pattern procedure.