a climbing turn to the holding altitude (e.g., “Climb to 900,  then climbing right turn to 2,500 direct ABC VOR and hold.”) When the MAP specifies holding at a facility or fix, the pilot  proceeds according to the missed approach track and pattern  depicted on the plan view. An alternate MAP may also be  issued by ATC. The textual description also specifies the  NAVAID(s) or radials that identify the holding fix. The profile view also depicts minimum, maximum,  recommended, and mandatory block altitudes used in  approaches. The minimum altitude is depicted with the  altitude underscored ( ). On final approach, aircraft are  required to maintain an altitude at or above the depicted  altitude until reaching the subsequent fix. The maximum  altitude is depicted with the altitude overscored ( ),  and aircraft must remain at or below the depicted altitude.  Mandatory altitudes are depicted with the altitude both  underscored and overscored ( ), and altitude is to be  maintained at the depicted value. Recommended altitudes  are advisory altitudes and are neither over- nor underscored.  When an over- or underscore spans two numbers, a  mandatory block altitude is indicated, and aircraft are  required to maintain altitude within the range of the two  numbers.  [Figures 1-11  and  1-12] The  Vertical Descent Angle (VDA) found on nonprecision  approach charts provides the pilot with information required  to establish a stabilized approach descent from the FAF or  stepdown fix to the TCH.  [Figure 1-17]  Pilots can use the  published angle and estimated or actual groundspeed to find  a target rate of descent using the rate of descent table in the  back of the TPP. two sets of minimums may be published depending upon  how the fix can be identified. Two sets of minimums may  also be published when a second altimeter source is used  in the procedure. The minimums ensure that final approach  obstacle clearance is provided from the start of the final  segment to the runway or MAP, whichever occurs last. The  same minimums apply to both day and night operations unless  different minimums are specified in the notes section of the  pilot briefing. Published circling minimums provide obstacle  clearance when pilots remain within the appropriate area of  protection.  [Figure 1-18] Minimums are specified for various aircraft approach  categories based upon a value 1.3 times the stalling speed  of the aircraft in the landing configuration at maximum  certified gross landing weight. If it is necessary to maneuver  at speeds in excess of the upper limit of a speed range for a  category, the minimums for the next higher category should  be used. For example, an aircraft that falls into category  A, but is circling to land at a speed in excess of 91 knots,  should use approach category B minimums when circling  to land.  [Figure 1-19] The minimums for straight-in and circling appear directly  under each aircraft category.  [Figure 1-19]  When there is  no solid division line between minimums for each category  on the rows for straight-in or circling, the minimums apply  to the two or more categories. The terms used to describe the minimum approach altitudes  differ between precision and nonprecision approaches.  Precision approaches use DH, which is referenced to the  height above threshold elevation (HAT). Nonprecision  approaches use MDA, referenced to “feet MSL.” The MDA  is also referenced to HAT for straight-in approaches, or  height above airport (HAA) for circling approaches. On  AeroNav Products charts, the figures listed parenthetically  are for military operations and are not used in civil aviation. Visibility figures are provided in statute miles or runway  visual range (RVR), which is reported in hundreds of feet.  RVR is measured by a transmissometer, which represents the  horizontal distance measured at points along the runway. It  is based on the sighting of either high intensity runway lights  or on the visual contrast of other targets, whichever yields  the greater visual range. RVR is horizontal visual range, not  slant visual range, and is used in lieu of prevailing visibility  in determining minimums for a particular runway. It is  illustrated in hundreds of feet if less than a mile (i.e., “24”  is an RVR of 2,400 feet).  [Figures 1-19  and  1-20] Visibility figures are depicted after the DA/DH or MDA in the  minimums section. If visibility in statute miles is indicated,  The minimums section sets forth the lowest altitude and  visibility requirements for the approach, whether precision  or nonprecision, straight-in or circling, or radar vectored.  When a fix is incorporated in a nonprecision final segment,  Landing Minimums 1-23 Figure 1-17.  Vertical descent angle (VDA).