Final Approach Segment

The final approach segment considered for obstacle clearance begins at the FAF and ends at the

runway or MAP, whichever is encountered last. A visual portion within the final approach segment may be included for straight-in non-precision approaches. The alignment and

dimensions of the final approach segment varies with the location and type of navigation facility.

10.8.1. Visual Area.

10.8.1.1. The visual area is an area evaluated for obstacles to determine whether night

operations must be prohibited because of close-in unlighted obstacles, or if visibility minimums must be restricted. There are three areas evaluated, depending on the type of final approach guidance and alignment with the runway centerline. They are: standard, straight-in, and offset.

10.8.1.2. The standard visual area is for runways to which an aircraft is authorized to circle. The standard visual area begins 200 feet from the threshold at the threshold elevation and extends out 10,000 feet along the runway centerline. The beginning width is 200 feet on either side of the centerline (400 feet total). The sides splay outward relative to the runway centerline.

Figure 10.5. Standard Visual Area.

10.8.1.3. The straight-in visual area is for runways with approach procedures aligned with the runway centerline. The visual area for a straight-in approach begins 200 feet from the threshold at the threshold elevation, and extends to the DH for precision procedures and the VDP (even if one is not published) for non-precision procedures. The beginning width of the visual area is 400 feet either side of the centerline (800 feet total). The sides splay outward relative to the runway centerline.

Figure 10.6. Straight-in Visual Area.

10.8.1.4. The offset visual area is for a straight-in approach not aligned with the runway centerline. When the final approach course does not coincide with the runway centerline, the visual area will be modified to account for this via a series of formulae. The exact dimensions and calculations are not important for aircrew to understand. It is important to remember that it is offset based on the angular difference of the final approach course and the extended runway centerline.

10.8.2. Obstacle Clearance in the Visual Area. Two obstacle identification surfaces (OIS) overlie the visual area with slopes of 20:1 and 34:1 from the approach end of the runway. When a runway is evaluated for circling, the 20:1 surface is used. When evaluating a runway for straight-in approaches, both the 20:1 and the 34:1 surfaces are used. Obstacles that penetrate either of these surfaces will affect visibility minimums for that runway.

10.8.2.1. 34:1 Slope Penetration. If the surface is penetrated by an obstacle, the TERPS specialist must take one of the following actions:

10.8.2.1.1. Coordinate with appropriate agencies to have the obstacle height adjusted or have the obstacle removed, or;

10.8.2.1.2. Limit the visibility to ¾ mile.

10.8.2.2. 20:1 Slope Penetration For a straight-in approach, if the 20:1 surface is penetrated, the TERPS specialist must take one of the following actions:

10.8.2.2.1. Coordinate with appropriate agencies to have the obstacle height adjusted or have the obstacle removed, or;

10.8.2.2.2. No VDP will be published, visibility will be limited to 1 mile, and the obstacles will be marked and lighted, or;

10.8.2.2.3. No VDP will be published, visibility will be limited to 1 mile, and a note will be published prohibiting the approach (both straight-in and circling) to the affected runway at night.

10.8.2.3. If the 20:1 surface is penetrated on circling runways, marking and lighting of the obstacle(s) is required or a note will be published prohibiting circling to the affected runway at night.

10.8.3. Descent Gradient. The optimum non-precision final segment descent gradient is 318 ft/nm, which approximates a 3° gradient. The maximum is 400 ft/nm, which approximates a 3.77° gradient. When the maximum descent gradient will be exceeded, then straight-in minimums will not be published.

10.8.3.1. NOTE: For RNAV (GPS), RNP, and Wide Area Augmentation System (WAAS) approaches see AFMAN 11-217 Volume 1, Instrument Flight Procedures Chapter 8 for discussion on descent angles for final approach.

10.8.4. Visual Descent Point. VDPs are applicable to straight-in approaches only. Where dual minimums are published, the lowest MDA is used to calculate the published VDP. If one is not published or you are going to fly to an MDA based on higher minima, you may compute your own VDP. However, when computing a VDP to use when one is not published, the pilot/aircrew need to carefully consider the information presented below. Additional information is found in AFMAN 11-217 Volume 1, Instrument Flight Procedures. A VDP may be published for all non-precision approaches, except as follows:

10.8.4.1. An obstacle penetrates the 20:1 surface.

10.8.4.2. When determination of the MDA is based on part-time or full-time remote altimeter settings, or;

10.8.4.3. When the VDP would be prior to a step-down fix, or;

10.8.4.4. When the VDP would be between the MAP and the end of the runway.

10.8.4.5. Even if all the parameters in paragraph’s 10.8.4.1 through 10.8.4.4 are met, the TERPS specialist is not required to publish a VDP.

10.8.4.5.1. NOTE: Since there is no way to determine if an obstacle prevented the a VDP from being published or it was due to another reason (listed above), pilots/aircrew need to exercise extreme caution when departing the MDA using their own VDP calculation in lieu of one that was not published.

10.8.5. Circling Approaches. The size of the circling area depends on the approach category of the aircraft. Some aircraft will be in a higher approach category for circling approaches based on the airspeed upon which the pilot chooses to fly the circling maneuver at. See AFMAN 11-217 Volume 1, Instrument Flight Procedures for airspeed ranges by aircraft category.

Figure 10.7. Circling Approach Area Construction.

10.8.5.1. Circling Obstacle Clearance. A minimum of 300 feet of obstacle clearance is provided in the circling approach area. The TERPS specialist may exclude certain sectors from

consideration where prominent obstacles exist in this area provided a safe approach and landing can be conducted without using the sector. In this case, a note is provided on the procedure excluding this sector from use during the circling maneuver with reference to the runway centerline(s). Sometimes illumination of certain runway lights may be required.

10.8.5.1.1. NOTE: There is no secondary obstacle clearance area for circling approaches.

10.8.5.1.2. NOTE: The circling area is determined by drawing a series of arcs of the

appropriate radius from the ends of each useable runway. The extremities of the adjacent arcs are joined with lines drawn tangent to the arcs. The arc radii distance will vary dependent on the aircrafts approach category. See figure 10.7.

10.9. Missed Approach Segment. A missed approach procedure will be established for every