descents, and instrument approaches. However, the Board has found that this device as installed and operated does not provide any information regarding the aircraft proximity to the ground during the final approach phase of a landing approach.
On November 10, 1971, in an aircraft accident report, NTSB-AAR-71-14, the Board recommended that a ground proximity warning device be developed for use during the approach and landing phase of flight. The Board further recommended that appropriate operating procedures be developed and imple- mented.
The Administrator's response to this recommendation stated in part: "...With respect to the recommendation to develop a ground proximity warning system for use during approach and landing, we believe the present instruments and procedures are safe and adequate. This presupposes that proper cockpit disciplines are maintained... We are, however, reassess- ing our system requirements for nonprecision straight-in approach systems with a view to providing additional assistance to the pilot in the form of ac- curate position information which will make his evaluation of the visual ap- proach segment less susceptible to human error..." (See Appendix G.)
Finally, on February 25, 1972, Board Report NTSB-AAR-72-4 contained a recommendation that the Administrator require all air carrier aircraft to be equipped with a functional ground proximity warning device in addition to the barometric altimeters. The Administrator's response continued to sup- port the earlier position quoted above. (See Appendix G.) In addition, the FAA advised the Board that they were developing new criteria which they proposed to apply to nonprecision approaches. One criterion involves establishing a final approach descent fix. This fix would be located at a point on the final approach from which a normal descent path of approximately 3° from MDA to touchdown could be commenced, provided the required visual reference was established. Pilots would be required to maintain an altitude at or above the MDA until passing this descent fix. Another criterion the FAA proposed will be to provide VASI for each runway served by a nonprecision approach. The VASI will provide vertical guidance at normal descent rates for the visual segment of the approach.
The Board believes that these two items will aid in preventing accidents that occur during nonprecision approaches and believes that these proposals are timely and appropriate. The Board also urges the FAA, wherever physically possible and within the limits of available resources, to convert approaches from nonprecision to precision at qualified airports through the installation of an ILS. In this connection, even the installation of a non- standard glide slope, such as the one currently in use at Huntington, is a substantial improvement in the aids available to a pilot in making his approach descent.
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