Air Carrier Captain reported there are notes on the Airport Diagrams for MFR and RDM airports; referencing the distance the PAPI is usable. Reporter stated the notes do not correspond to the AIM criteria for glide path obstruction clearance and could be misleading to pilots.

Narrative

On page 10-9 (26 NOV 21) for MFR/MFR Medford; OR Runway 32; there is a bubble note 2 for the PAPI-R. That note states; 'PAPI Rwy 32 does not provide obstruction clearance beyond 6.5 NM from threshold.' Per AIM 2-1-2-b Visual Glide Slope Indicators - 'The visual glide path of the PAPI typically provides safe obstruction clearance within plus or minus 10 degrees of the extended runway centerline and to 3.4 NM from the runway threshold.' Through research with multiple FAA and other safety professionals; we are unaware of any PAPI or VGSI that has a greater protected volume than the one stated in the AIM. The FAA's own procedures state that they are only to place notes that restrict standards not increase them. Unfortunately; the way this is written; the majority of pilots would incorrectly infer that they have safe obstruction clearance from 6.5 NM to the runway. They absolutely do not. Without these notes present; pilots can refer to either the AIM or the FOM and find the correct protection volume for a PAPI and not be misled into thinking that they have greater protection than they actually do.On page 10-9 (eff 10 Sep 20) for RDM/RDM Redmond; OR Runway 29; there is a bubble note 3 for the PAPI-L. That note states; 'Unusable beyond 5NM from threshold does not provide obstruction clearance.' Per AIM 2-1-2-b Visual Glide Slope Indicators -'The visual glide path of the PAPI typically provides safe obstruction clearance within plus or minus 10 degrees of the extended runway centerline and to 3.4 NM from the runway threshold.' Through research with multiple FAA and other safety professionals; we are unaware of any PAPI or VGSI that has a greater protected volume than the one stated in the AIM. The FAA's own procedures state that they are only to place notes that restrict standards not increase them. Unfortunately; the way this is written; the majority of pilots would incorrectly infer that they have safe obstruction clearance from 5NM to the runway. They absolutely do not. Additionally; the company XX-X page copies this same error in the Arrival/Departure section further reinforcing the information. Without these notes present; pilots can refer to either the AIM or the FOM and find the correct protection volume for a PAPI and not be misled into thinking that they have greater protection than they actually do.