DozyW -- re'your's on that 1979 B727 case "... line pilots knew about the use of CB's to pop the slats in cruise ... the NTSB and the FAA ... looking for an opportunity to end the practice..."
From inside, there never were any B727pilots who had done that "pop the slats" at Crz FL390: On Oct'2 1980, in Seattle, aboard the company's ship E209, TBC did the purported C/B drill -- it didn't work; TBC tried various methods, using various Circuit Breakers, eventually finding other combinations of C/Bs. Similarly, at the operator TWA, no pilots had done it -- never heard of it (but those second-hand rumors live-on). The IIC [Dean Kampshore] admitted this later, during deposition.
Re' INS into McMurdo, I had flown into McMurdo the during the Oct'78 re-supply, landing on the "ice". Just as we had done, ANZ also forced their INS's into "Grid" mode while south of 60S. These ANZ-guys had been given some extra training on INS & its weaknesses [the err-rate curve after 5-hours shoots up exponentially].
Re' the NDB, MacJob's _AD_ [Vol2, pg73, mid], contrary to the ANZ briefing, the McMurdo NDB was actually still operative during Nov'79 mishap.