A holding pattern

Share...Share on FacebookShare on VKTweet about this on TwitterShare on Google+Pin on PinterestShare on Reddit

A holding pattern is a procedure designed to keep an aircraft within a specified airspace while awaiting further clearance from ATC. In most cases it is used as a method of delaying a flight on its planned route.

A holding pattern involves holding fix, two turns and two straight-and-level legs as shown in Figure 6-5. The holding fix can be a VOR, an NDB, airway intersections, a point defined by a specific DME distance from a VOR on a specific radial, or an arbitrary RNAV-fix for aircraft appropriately equipped.
A standard holding uses right hand turns and a one minute inbound leg. The length of the outbound leg may vary a little to compensate for wind drift. Above 14 000 feet the leg length is extended to 1.5 minutes. It may also be extended by ATC.
Some holding patterns, rather than being based on time, are based on DME distance outbound. If a nonstandard pattern is to be flown, ATC will specify left turns.
At and below 14 000 feet MSL (no wind), the aircraft flies the specified course inbound to the fix, turns to the right 180  flies a parallel course outbound for 1 minute, again turns 180? to the right, and flies 1 minute inbound to the fix. Above 14 000 feet MSL, the inbound leg length is 1~0.5 minute.
During turns in a holding pattern, the rate of turn or bank angle should be 3? per second or 25? bank, whichever is less.
The timing for the  outbound leg usually starts at abeam or over the holding fix, which ever occur later. If that position cannot be determined (e.g. because the fix is a DME fix), start timing when you complete the mm outbound.

Entering a holding pattern, sometimes requires some maneuvering, as you might be approaching the pattern from any direction. There are three types of entrance maneuvers for a pattern. The type of entry you use depends on your heading as you approach the holding fix. Figure  shows the three sectors for a right-hand pattern. Entry sectors are established by forming angles of 70? on the holding pattern side of the holding course and 110? on the non-holding side. For leg-hand patterns all things discussed below apply in an analogous way. Entering from sector III (D) you will use a Direct Entry, from sector II (T) a Teardrop Entry, and from sector I (P) a Parallel Entry.


Direct Entry
The direct entry procedure is the most simple one and most published holdings are designed such that inbound traffic can most often use this simple method of entry. In a direct entry you simply fly to the fix and start the mm to the outbound leg. If your entry requires an outbound turn of less than 180 degree, start the mm with an appropriate delay. For instance, if the required mm is only 145 degree, start your turn 45?/3?/S= 13 seconds after crossing the holding fix. Without that delay your outbound leg would be too close to the inbound leg and the following turn at the outbound end would carry you out of the holding area.

Teardrop Entry
Fly to the fix and mm to a heading which starts a 30 degree teardrop on the holding side. Fly this heading for 1 minute and then start the mm to the inbound leg.

Parallel Entry
After passing the holding fix, turn to the outbound heading to parallel the inbound course, then turn inbound to the holding fix.

Example 1
A plane, MH 60?, receive this ATC clearance: “… HOLD EAST OF THE ABC VORTAC ON

What is the recommended procedure to enter the holding pattern?

First determine the holding fix, then dragging it on the holding radial given by ATC, this example inbound leg 90?, then return back to fix. Then draw the pattern from the fix with turns in the direction specified, this example is left turns.

The entry procedure is based on the aircraft’s heading. To determine which entry procedure to use, draw a line at 70? angle from the holding fix. With a heading 60 °, a parallel entry would be used.

comments powered by HyperComments