Whether you’re a seasoned instrument pilot or just starting out, here’s what you need to know about holding.
**Reasons for Holding**
Holding patterns are assigned to aircraft by ATC for various reasons. Holds are flown in protected airspace, away from obstacles, and can be published tracks off individual fixes or “random” holds assigned by ATC off a nearby NAVAID. Here are some of the most common reasons you might find yourself holding:
**Thunderstorms**: If there’s severe weather around your destination, arrival routes, instrument procedures, or the airport itself, it can affect your flight. The length of your hold depends on the location and speed of the storms. Fortunately, thunderstorms often change and move quickly, so most holds don’t last long.
**Flow Control**: Some airports are at maximum capacity all the time. You might be holding because the airspace is congested and it takes time to space out the aircraft along the limited number of approaches. ATC will usually give a projected timeframe for when you can join the arrival line.
**Low Visibility/Ceilings**: Low IFR conditions can slow down traffic flow. There’s no way for aircraft to see each other visually, so the separation minimums are increased.
**Snow Plowing**: If there’s recent snowfall or blowing snow that requires runway plowing, the hold depends on airport personnel. If you’re flying into an airport that gets snow frequently, it will take less time to clear the runway. But if you encounter a snowy day in Texas, you may have to wait a while.
**Problem at the Airport**: This is the worst-case scenario for holding. If there’s an emergency or an aircraft is stuck on the runway, especially at a single runway airport (such as San Diego), you might be delayed for a long time. Getting information from ATC can help you determine how serious the situation is and when to start your diversion planning.
**Holding Instructions**
The simplest holding instruction is a “hold as published” clearance, which is for holds shown on your IFR charts. You can find them on approach charts, STARs, or en-route charts. The clearance might sound like this: “123 hold south of the Cedar Lake VOR as published. Expect further clearance at 12:30 Zulu.” Note the light gray holding pattern next to the VOR on the chart.
“Random” holding is a bit more complicated. This happens when ATC gives you a non-charted hold. They’ll have to read out a full series of holding instructions. You should write them down to plan your hold. The clearance might sound like this: “123 hold west of the East Texas VOR, 290 radial, 20 DME, left turns, 5-mile legs. Expect further clearance at 12:30 Zulu.” Keep in mind that holding can occur anywhere en-route. The FAA says in Chapter 2 of the Instrument Procedures Handbook: “Unplanned holding at enroute fixes may be expected on airway or route radials, bearings, or courses. If the fix is a facility, unplanned holding could be on any radial or bearing and there may be holding limitations required if standard holding cannot be accomplished at the MEA or MRA.”
**Protected Airspace**
Holding is conducted in protected airspace determined by FAA TERPS Criteria. Holding patterns have a primary area for holding and a secondary area with a 2NM-wide perimeter around it. TERPS uses complex tables to determine the size of the holding area based on factors such as distance from the fix to the NAVAID, slant range distance, altitude, nearby holds, and aircraft speed. In most cases, you won’t know the exact dimensions of the protected airspace, but it’s important to understand that there’s enough buffer to ensure safety even at the max holding speeds, taking into account wind correction and varying groundspeeds. The FAA says that for level holding, there’s a minimum of 1,000 feet obstacle clearance in the primary area and 500 feet in the secondary area, with the clearance decreasing to zero at the outer edge. Allowance is made for precipitous terrain, and the obstacle clearance altitudes may be rounded to the nearest 100 feet.
**Maximum Holding Speeds**
The size of the holding pattern is directly related to the aircraft speed. To limit the amount of airspace protected by ATC, maximum holding speeds KIAS (Knots Indicated Airspeed) have been set for different altitude ranges. If a holding pattern has a nonstandard speed restriction, it’s shown with an icon indicating the limiting airspeed.
**Holding Entries**
There are three types of standard holding entries: direct, parallel, and teardrop. They’re simple procedures to help you establish your aircraft in the hold. Check out our live session below for a detailed explanation of all three holding entries.
What else do you want to know about holding? Let us know in the comments below.
