@underfire & aterps ref RNP criteria, VEB, et al
"Real"RNP is related to the criteria aligned with AC120-29A and 120-28D, as amplified by operators and entities doing the original RNP aircraft and procedure certs, representing the only criteria now successfully, safely, and widely used operational globally. That criteria is also still serving as the underlying basis for all modern large transport jet RNP related OEM avionics cert basis. It is the successful criteria used for virtually all real approach and departure RNP air carrier ops to date globally, starting back with KEGE (which essentially applied all the appropriate RNP principles, except for the RNP naming conventions), ....through the PAJN, CYLW, and NZQN eras. Regarding RNP.003, any RNP less than RNP .1 was intended to, and needs to accommodate factors like span and wheel to nav reference point height, at approach theta. RNP .003 is already in fact in practical use, since it is simply an equivalent lateral center of mass displacement reference formulation to the values used back as far as AC20-57 for autoland (before that criteria was absorbed and integrated into the later AC120-28 series). Reference VEB, [Real] VEB is a completely valid, honest, comprehensive, and scientific measure, as well as being operationally practical. [Real] VEB considers each relevant factor, including the three components of normal, rare-normal, and non-normal performance. [Real] VEB is a far better and more accurate characterization of vertical path performance than any of the obsolete faux scientific CRM and iso-probability contour methods that essentially remain the underlying basis of traditional, albeit now limited validity and obsolete criteria used in both TERPS and PANS-Ops. Which is typically why both of those legacy procedure type criteria still require some application of Kentucky windage common sense by specialists, use of "fudge factors" (such as "Precipitous Terrain"additives), and a 250' HAT ROC floor. VEB has absolutely nothing whatsoever to do with "Smoke and Mirrors". If found anywhere, smoke and mirrors would best be considered to apply to the domain of faux math, flawed assumptions, and fudge factors still underlying legacy TERPS and Pans-Ops. Q.E.D.