Holding Pattern Calculator: Entry & Timing

This calculator works out the three standard holding pattern entries (direct, parallel, and teardrop) and the timing for each leg, based on your current heading and the holding pattern’s inbound course. You enter your heading, the holding course, and the pattern’s turn direction, and you get the recommended entry procedure plus the outbound leg time. It is a planning tool for pilots to visualize and prepare for a hold before entering it.

Formula

The entry procedure is determined by the angle between your current heading and the holding pattern’s inbound course, combined with the turn direction. The standard method uses a 180-degree semicircle divided into sectors:

• Direct entry: Your heading is within a sector centered on the inbound course (about 70-110 degrees wide, depending on turn direction).
• Teardrop entry: Your heading is on the side opposite the turn direction, within a sector that requires a 30-degree offset turn.
• Parallel entry: Your heading is in the remaining sector, requiring you to fly parallel to the inbound course on the outbound side.

The outbound leg timing is based on altitude: 1 minute at or below 14,000 feet MSL, and 1.5 minutes above 14,000 feet MSL. The formula in the calculator uses the angle difference and turn direction to assign the entry type.

Worked Example

Using the default values: your heading is 180°, the inbound course is 090°, and the turn direction is Right.

1. Calculate the angle difference: (090 – 180 + 360) mod 360 = 270°.
2. Since 270° is greater than 180°, you are on the outbound side.
3. For a right turn, the sector for direct entry is within 70° of the inbound course (i.e., 020° to 160°). Your heading of 180° is outside this, so not direct.
4. The teardrop sector for right turns is from 160° to 290° (a 130° wide sector). Your heading of 180° falls in this range, so the entry is Teardrop.
5. Assuming you are at an altitude below 14,000 feet, the outbound time is 1.0 minute.

The calculator returns Teardrop and 1.0 min, matching the manual calculation.

When to Use This Calculator

Use this tool during pre-flight planning or while airborne when you are assigned a holding pattern by air traffic control. It is especially useful for:

• Preparing for a hold at a fix, VOR, or intersection.
• Practicing for instrument rating checkrides or proficiency flights.
• Briefing the entry before you arrive at the fix, reducing workload.

Remember that the calculator assumes standard holding pattern dimensions (e.g., 1-minute legs) and does not account for wind correction, which you will need to adjust for in actual flight.

How to Read the Result

The entry type tells you the initial maneuver to fly:

• Direct: Turn directly to the outbound heading and fly the outbound leg.
• Teardrop: Turn to a heading 30° offset from the outbound course (on the turn side), fly for the outbound time, then turn inbound.
• Parallel: Turn to the outbound heading, fly for the outbound time, then turn 180° to intercept the inbound course.

The outbound time is the duration to fly the outbound leg before turning inbound. Always adjust for wind by timing the inbound leg and correcting the outbound leg accordingly.

Common Mistakes and Limitations

• Unit mix-ups: Ensure headings are in degrees true or magnetic consistently. The calculator uses degrees, but you must input the same reference as your instruments.
• Turn direction: A common error is selecting the wrong turn direction. The holding pattern’s turn direction is specified by ATC or the chart; using the opposite will give an incorrect entry.
• Wind: The calculator ignores wind. In strong winds, the actual entry may differ slightly, and you must adjust headings and timing to maintain the pattern.
• Altitude: The outbound time is based on standard rules; some countries or special procedures may have different timings. Always follow your local regulations.

The calculator is a planning aid, not a substitute for proper instrument training or ATC instructions.

Alternatives and Related Tools

If you need more comprehensive holding pattern calculations, consider using an E6B flight computer or a dedicated aviation app that includes wind correction and graphical entry visualization. For practice, you can also use a holding pattern trainer that simulates the pattern and provides feedback. This calculator is intentionally simple for quick mental checks.

Frequently Asked Questions

How do I know the holding pattern turn direction?

The turn direction is given by ATC in the clearance (e.g., “hold northeast of the VOR, right turns”) or depicted on the instrument approach chart. If not specified, it is typically right turns (standard).

What if my heading is exactly on the boundary between sectors?

Boundary cases are ambiguous; the calculator assigns a result, but in practice, pilots are taught to choose the entry that is most comfortable and safe. Often, a direct entry is acceptable if you are within a few degrees.

Does this calculator work for non-standard holding patterns (e.g., 1.5-minute legs)?

It assumes standard 1-minute legs, but you can adjust the outbound time manually if you know the required time. The entry determination is based on angles and is unaffected by leg length.

Can I use this for DME holds?

Yes, the entry procedure is the same, but the outbound leg may be defined by a DME distance instead of time. The calculator only provides time, so you would use the DME distance from your navigation equipment.

Why does the calculator not account for wind?

Wind correction is an advanced skill that requires real-time data. The calculator gives the theoretical entry; you must adjust for wind while flying, typically by crabbing into the wind and timing the inbound leg.

Is the entry procedure mandatory?

No, the entry procedure is a recommended maneuver to establish the hold efficiently. Pilots may use any entry that keeps them within the protected airspace, but the standard entries are expected in training and testing.

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in hdg | Your heading | deg | 180 | 0
in crs | Inbound course | deg | 090 | 0
in turn | Turn direction | Left=1, Right=2
out entry | Recommended entry | - | if(mod(crs-hdg+360,360)