a pnr/cp is by definition always "critical"
Warren, I'll say it also. "CP" is the point of equal time back and on in the middle of the flight, timewise. It is
not the PNR, which is a totally different kettle of fish. The CP is also called the ETP.
the acronym LPSD latest point of safe diversion is also used.
Iccy, I have always considered that PNR and LPSD are different. LPSD is an offtrack PNR ie to a place off track. PNR, by definition, is the point of no
return to the place of departure.