of RNAV instrument approaches. This includes criteria for terminal arrival areas (TAAs), RNAV basic approach criteria, and specific final approach criteria for different types of RNAV approaches. 

## Terminal Arrival Areas 

The Terminal Arrival Area (TAA) provides a transition from the en route structure to the terminal environment with little required pilot/air traffic control interface for aircraft equipped with Area Navigation (RNAV) systems. TAAs provide minimum altitudes with standard obstacle clearance when operating within the TAA boundaries. TAAs are primarily used on RNAV approaches but may be used on an ILS approach when RNAV is the sole means for navigation to the IF; however, they are not normally used in areas of heavy concentration of air traffic . [Figure 4-36] 

The basic design of the RNAV procedure underlying the TAA is normally the “T” design (also called the “Basic T”). The “T” design incorporates two IAFs plus a dual purpose IF/IAF that functions as both an intermediate fix and an initial approach fix. The T configuration continues from the IF/IAF to the FAF and then to the MAP. The two base leg IAFs are typically aligned in a straight-line perpendicular to the intermediate course connecting at the IF/IAF. A Hold- in-Lieu-of Procedure Turn (HILO) is anchored at the IF/IAF and depicted on U.S. Government publications using the “hold−in−lieu−of−PT” holding pattern symbol. When the HILO is necessary for course alignment and/or descent, the dual purpose IF/IAF serves as an IAF during the entry into the pattern. Following entry into the HILO pattern and when flying a route or sector labeled “NoPT,” the dual- purpose fix serves as an IF, marking the beginning of the Intermediate Segment. 

The standard TAA based on the “T” design consists of three areas defined by the IAF legs and the intermediate segment course beginning at the IF/IAF. These areas are called the straight−in, left−base, and right−base areas. [Figure 4-36] TAA area lateral boundaries are identified by magnetic courses TO the IF/IAF. The straight−in area can be further divided into pie−shaped sectors with the boundaries identified by magnetic courses TO the IF/ IAF, and may contain step-down sections defined by arcs based on RNAV distances from the IF/IAF. 

Entry from the terminal area onto the procedure is normally accomplished via a no procedure turn (NoPT) routing or via a course reversal maneuver. The published procedure will be annotated “NoPT” to indicate when the course reversal is not authorized when flying within a particular TAA sector [Figures 4-36 and 4-37]. Otherwise, the pilot is expected to execute the course reversal under the provisions of 14 

CFR § 91.175. The pilot may elect to use the course reversal pattern when it is not required by the procedure, but must receive clearance from air traffic control before beginning the procedure. 

ATC should not clear an aircraft to the left base leg or right base leg IAF within a TAA at an intercept angle exceeding 90 degrees. Pilots must not execute the HILO course reversal when the sector or procedure segment is labeled “NoPT.” 

ATC may clear aircraft direct to the fix labeled IF/IAF if the course to the IF/IAF is within the straight-in sector labeled “NoPT” and the intercept angle does not exceed 90 degrees. Pilots are expected to proceed direct to the IF/ IAF and accomplish a straight-in approach. Do not execute HILO course reversal. Pilots are also expected to fly the straight−in approach when ATC provides radar vectors and monitoring to the IF/IAF and issues a“straight-in” approach clearance; otherwise, the pilot is expected to execute the HILO course reversal. (See AIM Paragraph 5−4−6, Approach Clearance) 

On rare occasions, ATC may clear the aircraft for an approach at the airport without specifying the approach procedure by name or by a specific approach (e.g., “cleared RNAV Runway 34 approach”) without specifying a particular IAF. In either case, the pilot should proceed direct to the IAF or to the IF/IAF associated with the sector that the aircraft will enter the TAA and join the approach course from that point and if required by that sector (i.e., sector is not labeled “NoPT), complete the HILO course reversal. 

Note: If approaching with a TO bearing that is on a sector boundary, the pilot is expected to proceed in accordance with a “NoPT” routing unless otherwise instructed by ATC. 

Altitudes published within the TAA replace the MSA alti­ tude. However, unlike MSA altitudes the TAA altitudes are operationally usable altitudes. These altitudes provide at least 1,000 feet of obstacle clearance, and more in moun­ tainous areas. It is important that the pilot knows which area of the TAA that the aircraft will enter in order to com­ ply with the minimum altitude requirements. The pilot can determine which area of the TAA the aircraft will enter by determining the magnetic bearing of the aircraft TO the fix labeled IF/IAF. The bearing should then be com­ pared to the published lateral boundary bearings that define the TAA areas. Do not use magnetic bearing to the right-base or left-base IAFs to determine position. 

An ATC clearance direct to an IAF or to the IF/IAF with­ out an approach clearance does not authorize a pilot to descend to a lower TAA altitude. If a pilot desires a low­ 

