8/15/19 AIM  f. Circling.  Circling minimums charted on an RNAV (GPS) approach chart may be lower than the LNAV/VNAV line of minima, but never lower than the LNAV line of minima (straight-in approach). Pilots may safely perform the circling maneuver at the circling published line of minima if the approach and circling maneuver is properly performed according to aircraft category and operational limitations. FIG 5 − 4 − 12 Example of LNAV and Circling Minima Lower Than LNAV/VNAV DA. Harrisburgh International RNAV (GPS) RWY 13 CATEGORY A B C D LPV DA 558/24  250 (300  − ½ ) LNAV/ VNAV DA 1572  −  5 1264 (1300  −  5) LNAV MDA 1180 / 24 872 (900  − ½ ) 1180 / 40 872 (900  − ¾ ) 1180 / 2 872 (900  −  2) 1180 / 2  ¼ 872 (900  −  2  ¼ ) CIRCLING 1180  −  1 870 (900  −  1) 1180  −  1  ¼ 870 (900  − ¼ ) 1180  −  2  ½ 870 (900  − ½ ) 1180  −  2  ¾ 870 (900  − ¾ ) FIG 5 − 4 − 13 Explanation of LNAV and/or Circling Minima Lower than LNAV/VNAV DA g. FIG 5 − 4 − 13 provides a visual representation of an obstacle evaluation and calculation of LNAV MDA, Circling MDA, LNAV/VNAV DA. 1. No vertical guidance (LNAV).  A line is drawn horizontal at obstacle height and 250 feet added for Required Obstacle Clearance (ROC). The controlling obstacle used to determine LNAV MDA can be different than the controlling obstacle used in determining ROC for circling MDA. Other factors may force a number larger than 250 ft to be added to the LNAV OCS. The number is rounded up to the next higher 20 foot increment. Arrival Procedures 5 − 4 − 18