How to correct for wind in a holding pattern

Holding, ICAO PANS-OPS. What is a hold? A hold is an instrument flying procedure defined in Doc 8168 Flight Procedures. It is defined as a predetermined manoeuvre which keeps an aircraft within a specified airspace while awaiting further clearance. Holding procedures are based on a holding fix, a geographical location that serves as a reference for a holding procedure. The holding fix can be a navigation aid such as a VOR or NDB. It can also be a fix offset from one of these aids at a given radial and distance, or in the case of RNAV holding, it can be a published waypoint. Holding procedures can most commonly be found on approach and arrival charts but also sometimes en route. Occasionally an unpublished hold can be given by air traffic control. You need to know about holding because it is a common feature in instrument flying. It can be given by air traffic control, required as part of a procedure, or even used tactically by pilots. It is an essential skill for any instrument-rated pilot. Aims: by the end of this video, you should know what a hold is, how a hold is defined, how to fly a hold, how to correct for wind in a hold. Holding construction and terminology. The hold is defined by the fix, the inbound track to the fix, and the direction of turn. This comes with some associated terminology such as the hold axis, the outbound leg and the abeam position. The hold axis splits the holding side, where the outbound leg and turns take place, from the non-holding side. Obstacle clearance criteria are based on holding on the holding side. There will also be a published minimum holding altitude which ensures 1,000 ft obstacle clearance within the holding area. There may also be a published limiting outbound distance or radial. If not, it is timed: 1 minute at or below 14,000 ft, 1 minute 30 seconds above 14,000 ft. Flying the hold. When flying the hold, there are a few important rules you must know. First, maximum speeds: this table is given, memorise the speeds for your current type. Secondly, angle of bank: turns are to be flown at 25 degrees angle of bank or rate one, whichever is less. Now for flying the hold, we'll start with the inbound leg. This is a tracked leg using radio navigation or RNAV as appropriate to maintain the published inbound track to the fix. On this leg, you can measure drift to assess the wind. To prepare for passing the fix, check the turn direction and bug the outbound heading. Have a timer ready. The outbound turn at rate one or 25 degrees angle of bank onto the outbound heading. In nil wind, this is the reciprocal of the inbound heading. Next is the outbound leg. This is a dead-reckoned leg that positions the aircraft appropriately for the turn onto the inbound track. It is by default timed. Else there may be a limiting radial or distance published. Timing begins from the abeam position, a QDR 90° to the hold axis. We are required to use established error check procedures, and on the outbound leg we can monitor for something called the gate. The gate is a QDR 30° from the hold axis. In a left-hand hold, outbound plus 30°; right-hand, minus 30°. This is where you would be at the end of a one-minute outbound leg in a light aircraft. Bug the inbound heading before the end of the outbound leg. At the outbound time, distance or radial, make a rate-one turn inbound. The aim of the inbound turn is to establish on the inbound track. Now you know what the gate is, how do you use it to monitor the outbound leg? Monitor for time and gate outbound. If you reach the gate before your outbound time, you are tight. Turn to track up the gate to the time. This puts you in the correct position to turn inbound. If you reach the time before the gate, you're wide. Turn inbound and anticipate an intercept. That leads us to the inbound turn. The goal is to intercept the inbound track. To do this proficiently and accurately, the turn should be monitored. If holding directly over or close to a navigation aid, you can monitor the progress and determine whether you're undershooting or overshooting. Check the turn at 90°, 60°, and 30° to go to the inbound heading. At 90° to go, the needle should be 15° from the inbound track. At 60° to go, the needle should be 10° from the inbound track. At 30° to go, the needle should be 5° from the inbound track. This will result in a smooth intercept. But what if that's not what you see? Here we have reached 90° to go, but the RMI is only 5° off. We have pushed the head of the needle too far. We should not increase angle of bank to chase it; we will overshoot. So pick a heading to reintercept the inbound track and continue through to this. Make sure you stop the turn with the heading on the correct side of the needle to reintercept. Anticipate rate of movement to turn onto the inbound course. In the other case here, we have reached 90° to go but the RMI has not yet reached 15°. It needs to be pushed further. We are wide and need to intercept. It's too late to stop the turn here, so plan to stop at the next check, 60° to go. At 60° to go, roll the wings level and fly until the RMI is in the correct position for this heading, 10° off. Then roll back into the turn. This should again achieve a smooth intercept. Now you're back on the inbound track. Continue in the hold as usual. Correcting for wind in the hold. We are required to correct for the effects of wind with regards to heading and timing such that we are able to establish the inbound track before passing the fix. This helps ensure obstacle clearance and positions us correctly for any associated procedure. Here's some holding patterns with various winds where no correction has been made. You can see that in anything more than a light wind, heading and timing corrections are essential. How to correct? In the hold, we have one tracked leg, the inbound leg, on which drift can be assessed and corrected. We then have the outbound turn, outbound leg and inbound turn. This is approximately 3 minutes of flying where we are subject to drift. We cannot easily correct for drift in the turns, so we have to make the correction on the outbound leg. If we have 3 minutes of drift to correct for and 1 minute in which to correct for it, one solution is to apply triple the drift on this one leg. But how much is single drift? Drift on inbound and outbound legs is approximately equal. Use the clock code to calculate drift, or look at the difference between heading and track when on the inbound leg. Multiply this figure by three to have triple drift. Apply triple drift into wind outbound. Here's an example. In this scenario, flying at 120 knots true airspeed with a hold of 360° left-hand and a wind of 090° at 15 knots. Single drift is approximately 7.5° as seen on the inbound leg. Three times this makes triple drift approximately 22°. Applying this outbound into wind gives an outbound heading of 158°. Let's see how this works out. The outbound turn is stretched by the wind here. Our inbound turn will also be compressed. The outbound leg is spent tracking back towards the hold axis to correct for both these turns and the drift on the outbound leg. The gate would normally be 210°. However, it moves into wind by approximately single drift. Timing is also corrected: 1 second per knot of headwind or tailwind outbound. Add time for a headwind, reduce for a tailwind. You can see triple the drift applied into wind has corrected for drift in the hold and we regain the inbound leg before the fix. The adjustment to timing helps ensure that we remain in the holding area. There is one further consideration. If your triple-drift corrected heading falls within 30° of the wind, reduce to double drift. Here's one more example. Here we have a 090° left-hand hold with a wind of 310° at 30 knots. Single drift is 10°, triple drift 30°. This would make an outbound heading of 300°. However, this is within 30° of the wind, so we reduce to double drift, making an outbound heading of 290° and a time of 1 minute 28 seconds. Let's see how this works. As you can see, it's worked out well. If we hadn't reduced to double drift, we would find ourselves wide and have to correct.