The DGCA, India, issued a new Civil Aviation Requirement, SECTION 8 – AIRCRAFT OPERATIONS SERIES ‘C’ PART I (click for PDF) on the 13th of June, 2011, on All Weather Operations (AWO). Due to the extended operational impact of this CAR, a great amount of Jeppesen charts were affected. (See Chart Alert), the most noticable of which is a grey shaded box in the profile.

Note the "Grey Area" in the approach profile.

The CAR lays out that all non-precision approaches (NPA) shall be flown using the Continuous Descent Final Approaches (CDFA) technique unless otherwise approved by the DGCA for a particular approach to a particular runway.

Compared to the traditional descent  approach technique, where the aircraft descends step-by-step prior to the next minimum altitude, the CDFA technique has safety and operational advantages, such  as standardization of procedures, simplification of the decision process  (one technique, one decision at one point), increased height above obstacles, use of a  stable flight path,  reduced noise and reduced fuel burn. The CDFA technique can be flown on most published approach when VNAV or ILS is not available. When electronic  or a pre-stored computed vertical guidance is not used, vertical speed or flight path angle may be used to achieve a CDFA profile.

This has few implications. Air crews can no longer level out at the MDA and fly to the MAP to execute a go around. Instead, the go-around must be executed at the MDA, or the MAP, whichever occurs first. Also, the go around must be flown through the MAP, unless otherwise specified. Hence, the pull up arrow is at the point where the CDFA and the MDA intersect.

In case of ILS approaches, the CDFA and the Glide path are identical. The CDFA is enforced when the Glide Slope is out of service, in which case, go-around must be initiated at the point where the glide path and the MDA intersect.

Because the concept of levelling off at MDA no longer exists, there are chances of flying below the MDA, in case of executing a missed approach at MDA when flying a CDFA. Further, the MDA may be reached either before or after the intended vertical path, due to vertical path errors involved with a non-precision approach. For this reason, the MDA is emphasised in the segment between the MAP and the ALTITUDE-DME check preceding the MAP.

The Jeppesen chart profile depiction will be modified to show the continuous descent on final approach. DGCA published minimum altitudes will be shown as segment minimum altitudes in the profile (grey shaded box). These minimum altitudes are typically provided for obstacle clearance and must not be violated to remain clear of obstacles or terrain.

Zoomed in to the vertical profile