DozyW - You’re doing a fine job but there are two points that have yet to be put to bed. You would accept that if the captain had received conflicting information about the final waypoint, then he had to check it if he planned on going below MSA. You say that there was no conflict re the information but, in fact, there was: The briefing used slides and an audiotape. When making the audiotape the briefing officer read from a script. Both the tape and the script were produced as exhibits to the Royal Commission, so there is no doubting that the words in the script were actually heard by those in attendance. I have a copy of the script, which was Exhibit 12. This is what it says: “A standard route definition will be used employing the From-Via-To format. Enter NZAA then 78S/167E this being the approximate co-ordinates of McMurdo Station.”
What was said at the briefing leads into the other point that requires an explanation: Why did the captain decide to turn left when attempting to climb out? The logical explanation is what was said at the briefing: “Your nav track goes to McMurdo Station.”
The night before, the captain plotted the track on his atlas and discovered that it went from Cape Hallett to a point 20nm to the west of McMurdo Station. He would have also noted that a track from Cape Hallett direct to McMurdo Station went over Erebus, but not to worry, because that wasn’t to be his track. So he folds up his paperwork and goes to bed. The next morning, he and the F/O manually entered the co-ordinates – but he never checked that final waypoint. And he had plenty of time to check it on the way down, but never did. There would have been a pre-descent briefing, where going below MSA would have been discussed. At that point, it was imperative that he check the final waypoint, because that was the only thing keeping the aircraft from hitting terrain, and yet he did nothing. The problem only dawned on him at 1500 feet in the jaws of Lewis Bay when the F/E expressed alarm and he decided to climb out. The F/O told him it was clear to the right, but pennies were starting to drop very quickly and he recalled what was said at the briefing, realised he should have checked the final waypoint, and appreciated that Erebus might be dead ahead, which would explain the radio problems. If so, the only way out would be to the left, so he overruled the F/O, pulled out the knob, and initiated a left turn using the autopilot.