Introduction to Instrument Approach Procedures

In this lesson we are going to learn about the different categories of Instrument Approach Procedures as well as introduce you to the PTAC acronym. Let's begin by defining an Instrument Approach Procedure.

Pilot/Controller Glossary

Instrument Approach Procedure Categories

We can classify all Instrument Approach Procedures into one of two categories: Precision and Non-Precision. Let's look at the difference between the two:

• Precision Approach - A precision approach is an approach that provides both lateral and vertical guidance. These approaches have lower minimums than their non-precision counterparts. Some examples of this type of approach are ILS or GPS (with WAAS)

• Non-Precision Approach - A non-precision approach is an approach that provides only lateral guidance to the aircraft. Due to there not being any vertical guidance provided, this type of approach has higher minimums than their precision counterpart. Some examples of this type of approaches are VOR/NDB/GPS/LOC/etc.

The PTAC Acronym

Let's learn about the PTAC acronym. PTAC is an acronym to help you remember the order of items in which to issue an approach clearance. Let's look at what the PTAC Acronym stands for:

• P (Position) - This is the aircraft's position relative to a fix depicted on the Instrument Approach Plate. This is only required if you are providing vectors to the final approach course.

• T (Turn/Direct) - This is a turn given to an aircraft to join the final approach course, or the instructions to proceed direct a fix if sending the aircraft towards an Initial Approach Fix (IAF).

• A (Altitude) - This is the altitude for the aircraft to maintain until established on a segment of the approach. This is not required when the aircraft is not on a published route or segment of the approach, or if they are on an airway that will overfly an IAF.

• C (Clearance) - This is the clearance for the aircraft to actually fly the approach. The most basic form of an approach clearance is "CLEARED APPROACH"

• If you wish a particular type of approach to be flown, then you must state the type of approach. "CLEARED (type) APPROACH"

• If there is more than one approach of any particular type (such as ILS23 and ILS14) then you will need to specify which approach you would like the pilot to fly. "CLEARED (type)(designator) APPROACH"

• Finally if the aircraft is making an approach into a satellite or uncontrolled field, you will need to state the airport in which the procedure is located. "CLEARED (optional: Type/designator) APPROACH INTO (airport)"

If this does not make sense do not worry! We will show you how to use PTAC when issuing clearances in the next couple of lessons.

NEXT: Vectoring to the Initial Approach Fix

PREVIOUS: Introduction to Vectoring

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