CS ADR-DSN.M.640 Visual approach slope indicator systems
ED Decision 2014/013/R
The safety objective of visual approach slope indicators is to provide information on the approach angle necessary to maintain a safe height over obstacles and threshold.
(a) A visual approach slope indicator system should be provided to serve the approach to a runway where one or more of the following conditions exist:
(1) the runway is used by turbojet or other aeroplanes with similar approach guidance requirements;
(2) the pilot of any type of aeroplane may have difficulty in judging the approach due to:
(i) inadequate visual guidance such as is experienced during an approach over water or featureless terrain by day or in the absence of sufficient extraneous lights in the approach area by night; or
(ii) misleading information such as is produced by deceptive surrounding terrain or runway slopes.
(3) the presence of objects in the approach area may involve serious hazard if an aeroplane descends below the normal approach path, particularly if there are no non-visual or other visual aids to give warning of such objects;
(4) physical conditions at either end of the runway present a serious hazard in the event of an aeroplane undershooting or overrunning the runway; and
(5) terrain or prevalent meteorological conditions are such that the aeroplane may be subjected to unusual turbulence during approach.
(b) The standard visual approach slope indicator systems should consist of PAPI and APAPI systems conforming to the specifications, as prescribed in CS ADR-DSN.M.645 to CS ADR-DSN.M.655.
(c) PAPI should be provided where the code number is 3 or 4 when one or more of the conditions specified in paragraph (a) above exist.
(d) PAPI or APAPI should be provided where the code number is 1 or 2 when one or more of the conditions specified in paragraph (a) above exist.