I guess this is part of the coverup
https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf...
and
https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf...
and
https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf...
and
https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf...
there's about ~20 total unique if I recall. Some supersede others.