by Jonathan M. Stern
The plan view depicts the overhead view of the entire approach procedure, including navigation aids used to arrive at and conduct the instrument approach, the missed approach procedure (to be followed if a landing cannot be made), the runway layout, portrayed obstructions, feeder routes, outbound and inbound courses, and procedure turns (or other methods of course reversal).
Navigation aids are identified both by a symbol for the navaid, and by a navaid facility box, which contains the name of the navaid, its frequency, and identifiers, both Morse Code and name. Rectangular navaid boxes identify VORs, NDBs, LOMs, localizers, LDAs, and SDFs. LDA stands for localizer-type directional aid, which is a localizer-like approach not aligned with the associated runway.
An LDA may or may not have a glideslope. An SDF, or simplified directional facility approach, is also similar to a localizer, but it is less precise. The navaid box for the facility on which the instrument approach procedure is based is in a thicker lined box.
Obstacles are depicted by an upside-down V shape with a dot inside. The highest charted obstruction is indicated by a larger black dot. There may, however, be higher terrain or obstructions in the area not reflected on the chart, Accordingly, this symbol (and its associated altitude) cannot be used generally for obstruction avoidance. Spot elevations are shown next to a black dot, and the highest spot elevation is shown by a larger dot.
Feeder routes, which provide a course and altitude to be flown to transition from the enroute structure to the approach structure, are shown with thick black lines. Along with each feeder route is a depiction of distance in nautical miles and a minimum altitude. When thin lines are used to identify intersections or lead radials, they are not flyable as part of the approach procedure, and no altitude or distance information is provided.
When a procedure turn is depicted on the chart, any type of procedure may be used to perform the required course reversal so long as the reversal is made on the side of the approach course indicated by the depicted procedure turn within the distance indicated in the profile view.
The minimum safe altitude (MSA) circle shows the altitude(s) that within 25 nautical miles of the specified facility provides at least 1,000 feet of obstacle and terrain clearance. The MSA circle may be divided into sectors, but none is smaller than 90°. The MSA is for emergency use only, and communication and navigation reception is not ensured at the specified minimum altitudes.