at the airport is labeled with the letter A, and the lettering  continues in alphabetical order (e.g., “VOR-A or “LDA-B”).  The letter designation signifies the expectation is for the  procedure to culminate in a circling approach to land. As a  general rule, circling-only approaches are designed for one  of the two following reasons: • The final approach course alignment with the runway  centerline exceeds 30º. • The descent gradient is greater than 400 FPNM from  the final approach fix (FAF) to the threshold crossing  height (TCH). When this maximum gradient is  exceeded, the circling-only approach procedure may  be designed to meet the gradient criteria limits.  Further information on this topic can be found in the  Instrument Procedures Handbook, Chapter 4, under  Approach Naming Chart Conventions. To distinguish between the left, right, and center runways,  an “L,” “R,” or “C” follows the runway number (e.g., “ILS  RWY 16R”). In some cases, an airport might have more than  one circling approach, shown as VOR-A, VOR/DME-B, etc.  More than one navigational system separated by a slash  indicates more than one type of equipment is required to  execute the final approach (e.g., VOR/DME RWY 31).  More than one navigational system separated by “or”  indicates either type of equipment may be used to execute  the final approach (e.g., VOR or GPS RWY 15). Multiple  approaches of the same type, to the same runway and using  the same guidance, have an additional letter from the end of  the alphabet, number, or term in the title (e.g., ILS Z RWY  28, SILVER ILS RWY 28, or ILS 2 RWY 28). VOR/DME  RNAV approaches are identified as VOR/DME RNAV  RWY (runway number). Helicopters have special IAPs  designated with COPTER in the procedure identification  (e.g., COPTER LOC/DME 25L). Other types of navigation  systems may be required to execute other portions of the  approach prior to intercepting the final approach segment  or during the missed approach. The pilot briefing is located at the top of the chart and  provides the pilot with information required to complete  the published approach procedure. Included in the pilot  briefing are the NAVAID providing approach guidance,  its frequency, the final approach course, and runway  information. A notes section contains additional procedural  information. For example, a procedural note might indicate  restrictions for circling maneuvers. Some other notes might  concern a local altimeter setting and the resulting change  in the minimums. The use of RADAR may also be noted in  this section. Additional notes may be found in the plan view. Concentric dashed circles, or concentric rings around the  distance circle, are used when the information necessary to  the procedure will not fit to scale within the limits of the plan  view area. They serve as a means to systematically arrange  this information in its relative position outside and beyond  the reference circle. These concentric rings are labeled en  route facilities and feeder facilities.  Some AeroNav Products charts contain a reference or  distance circle with a specified radius (10 NM is most  common). Normally, approach features within the plan  view are shown to scale; however, only the data within the  reference circle is always drawn to scale.  The plan view provides a graphical overhead view of the  procedure and depicts the routes that guide the pilot from  the en route segments to the initial approach fix (IAF).  [Figure 1-10]  During the initial approach, the aircraft has  departed the en route phase of flight and is maneuvering to enter  an intermediate or final segment of the instrument approach.  An initial approach can be made along prescribed routes within  the terminal area, which may be along an arc, radial, course,  heading, radar vector, or a combination thereof. Procedure turns  and high-altitude teardrop penetrations are initial approach  segments. Features of the plan view, including the procedure  turn, obstacle elevation, minimum safe altitude (MSA), and  procedure track are depicted in  Figure 1-11 . Terrain is depicted  in the plan view portion of all IAPs if the terrain within the  plan view exceeds 4,000 feet above the airport elevation, or if  within a 6 NM radius of the airport reference point the terrain  rises at least 2,000 feet above the airport elevation. Communication frequencies are listed in the order in which  they would be used during the approach. Frequencies for  weather and related facilities are included, where applicable,  such as ATIS, ASOS, AWOS, and AFSSs. When a triangle containing a “T” ( ) appears in the notes  section, it signifies the airport has nonstandard IFR takeoff  minimums. Pilots should refer to the DPs section of the TPP  to determine takeoff minimums. When a triangle containing an “A” ( ) appears in the notes  section, it signifies the airport has nonstandard IFR alternate  minimums. Civil pilots should refer to the Alternate Minimums  Section of the TPP to determine alternate minimums. Military  pilots should refer to appropriate regulations. When a triangle containing an “A” NA ( ) appears in  the notes area, it signifies that Alternate Minimums are Not  Authorized due to unmonitored facility or the absence of  weather reporting service. The Plan View The  Pilot Briefing 1-16