slast:
Hi Tom
You're dead right that there are a lot of good lessons from way back being forgotten. Good to see Joe O and Larry DeC referenced!
By coincidence I was just looking up some stuff from the original OPSP in Montreal......... happy (!?!) days...
I'm the third name Tom mentions. Larry D. and I did a fair amount of work together.
There are more issues and limitations with RNP AR than benefits. It DOES provide wonderful benefits for those who have IRUs and all the attendant redundancies, and are will to go through a vary onerous certification, training, qualification, and database maintenance process. That bar is far too high for most.
And, RNP AR, as good as it is for the very rich to get into Rifle, Colorado, it is being horribly over-implemented at air carrier airports that have perfectly good ILS.
Is to BHM, the crew was mandated to NOT leave MDA unless they had the PAPI in view and used its vertical guidance to nearing the threshold. Or, they could have held for a few minutes until the ILS runway was reopened.
Runways the like of 18 at BHM will not have a vertically guided approach with the FAA's terrain and obstacle free runway zone requirements. Those standards have become much more conservative than even 15 years ago.