IFH 1-23

Final Approach Angle for Vertical Path ComputersFigure 1-17. Vertical descent angle (VDA). 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. Landing Minimums 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, 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,