BY ORDER OF THE SECRETARY OF THE AIR FORCE AIR FORCE ...

AFMAN 11-217V1 3 JANUARY 2005 173
8.5.4.4.7. Final Approach Direction. The arrow shows the direction the final
approach brings you in relation to the runway. This information can help you
know where to look for the runway. It is also useful in determining how much
maneuvering may be required to align the aircraft with the runway. A straight-in
approach may bring your aircraft to the runway as much as 30 degrees off of the
runway centerline and still be considered a straight-in approach.
8.5.4.5. Additional Information. Look carefully for notes on the IAP. Notes are used
to identify either nonstandard IAP criteria or to emphasize areas essential for the safe
completion of the approach.
8.5.4.6. Visual Descent Point (VDP). The VDP is a defined point on the final
approach course of a non-precision straight-in approach procedure from which a
normal descent (approximately 3°) from the MDA to the runway touchdown point
may be commenced, provided visual reference with the runway environment is
established. The VDP is normally identified by DME and is computed for the nonprecision
approach with the lowest MDA on the IAP. A 75 MHz marker may be used
on those procedures where DME cannot be implemented. VDPs are not a mandatory
part of the procedure, but are intended to provide additional guidance where they are
implemented. A visual approach slope indicator (VASI) lighting system is normally
available at locations where VDPs are established. Where VASI is installed, the VDP
and VASI glide paths are normally coincident. If VASI is not installed, the descent is
computed from the MDA to the runway threshold. On multi-facility approaches, the
depicted VDP will be for the lowest MDA published. Therefore, on an approach with
a higher MDA, the published VDP will not be correct and must be computed by the
pilot. No special technique is required to fly a procedure with a VDP; however, to be
assured of the proper obstacle clearance, the pilot should not descend below the MDA
before reaching the VDP and acquiring the necessary visual reference with the
runway environment. The VDP is identified on the profile view of the approach chart
by the symbol “V” (Figure 8.16).
8.5.4.6.1. In some cases a published VDP may be absent from an IAP due to an
obstacle that penetrates a 20:1 surface. In addition, there was a period of time
where the FAA did not place any emphasis on publishing VDPs on IAPs. As a
result, many IAPs were designed without published VDPs. The problem is that
when a IAP is published without a VDP, there is no way for the pilot to know if it
is due to an obstacle penetration, or because the TERPS specialist just did not
publish it. If performing a non-precision approach to an unfamiliar field at night
(or very low visibility) without a published VDP, and no visual or “normal”
electronic glide path guidance to that runway is available, use caution when
departing the MDA, as there could potentially be an obstacle penetrating the 20:1
surface. See Chapter 15, Visual Glide Slope Indicators (VGSI) for more
information on obstacles in the 20:1 surface.