TERPS is still outdated and flawed
@ aterpster - TERPS is still severely obsolete and conceptually flawed, including the GQS (and CRM). [Real] RNP, properly implemented, is most capable of addressing KBHM 18, and virtually every other jet air carrier runway globally. RNP's VNAV can provide safe aligned guidance all the way to the to the TDZ, and back out, 100% of the time, even after a first engine failure and 1st nav failure. It is sad to see the ways that some [perhaps well-meaning] authorities have now corrupted [real] RNP with unnecessary and inappropriate criteria baggage being added or modified from the original intent. That regulatory authority criteria "fault" is still unnecessarily putting at risk air carrier operations globally, just as we've now seen at KBHM. There is absolutely no valid scientific reason why a 200' HAT DA(H) couldn't be achieved on KBHM 18 with [real] RNP, and an appropriate application of the VEB. In Australia recently it was even successfully used in Cat III conditions to a safe landing, under non-normal circumstances. [Real] RNP now, and soon GLS, can fix all this to at least lowest Cat I minima, and with GBAS, to Cat III minima, even at KBHM 18.