Holds and Holding

Instrument Holds and Holding

Preface

Few things seems to bring angst to the instrument pilot like an unexpected hold. For some pilots, even the entry into a published hold is high on the stress-o-meter. But, like most things in instrument flying (or flying in general, for that matter), holds needn't be a source of dread. The key is to be armed with knowledge - if you know what to expect, and how to execute what is expected of you, the world (or cockpit) is suddenly a much more hospitable place.

In this lesson I will point out the key points of the hold that every pilot should know. I will also provide relevant references and encourage you to read and learn the complete details from the official sources.

References

I highly recommend that you take the time to read the entire AIM entry on holding. There is far more information there than it makes sense to reproduce here. Much of the additional information is less commonly used, but it is good to at least be aware of none-the-less.

1. AIM 5-3-8 Chapter 5, Section 3. Holding - The comprehensive and official reference

Holding Parameters

The following information is required to specify a hold. But this information may be provided in different ways: explicitly by ATC, specified on a chart or approach, assumed to be a default or previously provided value if otherwise not provided, or some combination thereof.

1. Direction of holding from the fix in terms of the eight cardinal compass points (i.e., N, NE, E, SE, etc.).
2. Holding fix (the fix may be omitted if included at the beginning of the transmission as the clearance limit).
3. Radial, course, bearing, airway or route on which the aircraft is to hold.
4. Leg length in miles if DME or RNAV is to be used (leg length will be specified in minutes on pilot request or if the controller considers it necessary). [default: 1 minute]
5. Direction of turn if left turns are to be made, the pilot requests, or the controller considers it necessary. [default: right turns]
6. Time to expect further clearance and any pertinent additional delay information.

A Common Error / Confusion

Many instrument pilots get confused when given holding instructions verbally. The problem usually has to do with the appearance of a conflict between the "direction of holding" and the "radial" (or equivalent). Here's the cause, and the solution:

1. The "direction of holding from the fix" always specifies the area in which the holding will take place.
2. The "radial, course, bearing, airway, or route" always specifies the line on which to hold, not necessarily the inbound course.
3. Depending on the situation, it is often the case that the two (direction vs radial (or equivalent)) will seem to be in conflict with each other. This is the equivalent of being told to fly TO a VOR on a specified radial - where you need to fly the reciprocal in order to fly inbound since radials are always outbound.
4. Note that the inbound course is always the reciprocal of the "direction of holding," regardless of how the course is specified. So, for example, if you are told to "hold North ..." your inbound course will always be South (although the exact course will depend on the specified "radial" (or equivalent)).
5. The solution: Always fly the reciprocal of the "direction of holding" (adjusting for the exact course, of course).

Entry Into the Hold

There are three legitimate entries into a hold: Direct (C), Parallel (A), and Teardrop (B) - see figure 5-3-4 Holding Pattern Entry Procedures (reproduced, above). When entering a hold you should use the entry procedure appropriate to your sector of entry as specified in figure AIM 5-3-4. In each case, you should:

1. Fly the holding fix (usually direct, or on a specified airway or radial)
2. Turn as specified for the entry:
   • DIRECT - Turn in the direction of the hold to the outbound heading
   • PARALLEL - Turn in the opposite direction of the hold to the outbound heading (this should be roughly parallel to, and in relative close proximity to, the inbound leg)
   • TEARDROP - Turn in the direction of the hold, but at an angle (referred to here as the delta) to the outside of the outbound heading (the value will be +/- to the outbound heading, depending on if it is left or right traffic). The exact offset angle, or delta, is a function of the leg length (and ground speed, if the hold is specified by distance vs time). The default is a 30° delta for 1 a minute leg length. If you do the math (assuming calm winds) you come up with the following angles for various holds:
     • 1 minute legs = 32° ⇒ ≈ 30° delta
     • 1-1/2 minute = 23° ⇒ ≈ 25° delta
     • 4-5 NM, 90-120 KTS = 11-18° ⇒ ≈ 15° delta
3. Fly outbound for the specified time or distance
4. Turn towards the inbound course:
   • DIRECT - Turn in the direction of the hold to approximately the inbound heading and adjust as necessary to intercept
   • PARALLEL - Turn in the direction opposite the hold for approximately 135° to approximately a 45° intercept to the inbound course (or fly directly to the fix and intercept at the fix)
   • TEARDROP - Turn in the direction of the hold to approximately the inbound heading and adjust as necessary to intercept
5. Intercept, capture, and track the inbound course
6. Upon reaching the holding fix you are now established in the hold and may proceed holding as specified

Holding Once Established

Once you have successfully entered the hold, holding is relative straight-forward. Once established in the hold, make sure to treat the fix as a fly-over waypoint (no turn anticipation) and:

1. Fly towards the fix on the inbound course
2. Upon reaching the fix (at the first sign of a course reversal for a VOR), start a standard rate turn in the direction of the hold
3. Roll out on the outbound heading, adjusted for winds - for a 1 minute hold, this should be -3X the wind correction angle (WCA) noted on the inbound leg. Distance holds will typically require less of a multiplier.
4. Fly outbound on the adjusted heading for the specified distance, or time (adjusted based on the inbound leg timing - timing is specified for the inbound leg, so that is your target)
5. Upon reaching the specified distance or time (adjusted), start a standard rate turn in the direction of the hold towards the inbound course,
6. Adjust your heading to intercept the inbound course
7. Once established on the inbound course, note the time (if timed legs), and the required WCA (wind correction angle) to hold the inbound course to the fix.