So does that mean a PAPI does not count?FAR 91.175 (3) Except for a Category II or Category III approach where any necessary visual reference requirements are specified by the Administrator, at least one of the following visual references for the intended runway is distinctly visible and identifiable to the pilot:
(i) The approach light system, except that the pilot may not descend below 100 feet above the touchdown zone elevation using the approach lights as a reference unless the red terminating bars or the red side row bars are also distinctly visible and identifiable.
(ii) The threshold.
(iii) The threshold markings.
(iv) The threshold lights.
(v) The runway end identifier lights.
(vi) The visual approach slope indicator.
(vii) The touchdown zone or touchdown zone markings.
(viii) The touchdown zone lights.
(ix) The runway or runway markings.
(x) The runway lights.
I have had this question in the back of my head for awhile and today just as I was teaching it to a student the DPE walked in and I asked him about it. This turned into a 3 CFIs and the DPE opening their respective FAR/AIMs looking for the answer. He said to check the definitions in FAR 1 to see if a visual approach slope indicator might be defined as a catch all term. No mention there.
In AIM 2-1-2 titled "Visual Glideslope indicators", the VASI is the first one listed, along with the PAPI, Tri-Color VASI, Pulsating VASI, and Alignment of Elements systems. The published visual ranges in the AIM are the same.
We concluded that there was no definite answer but that it is most likely just another poorly written FAR.