SR71:
Cape Hallett – Clear weather. The passengers took photos of it. I haven’t seen these photos, but I’ve seen other photos of Cape Hallett. It’s a very impressive sight and would have been one of the highlights of the flights.
Drift in the AINS – The actual impact position was about 3nm off the nav track position, ie, not much. But I’m not suggesting that drift was the primary potential problem with the AINS. The primary problem was the human input.
Communication problems – Agreed: The crew can’t be blamed for that penny not dropping. To do so would be to engage in “Monday Morning Quarterbacking”, as Pakeha Boy calls it.
“Know” and “Sure” – This is more of lawyer’s issue, but I would say that you can be sure that the world is flat, but you can’t know that the world is flat, cos it isn’t. Putting the semantics to one side, isn’t the real issue the independent verification? Even if the crew had obtained the radar fix, they still wouldn’t know their position to the level of 100% certainty, because the radar operator might have made a mistake. But the chance of two independent navigation aids both being wrong at the same time is so remote that it can be discounted. I still can’t accept that you have sufficient knowledge of your position by simply locking on to the nav track, because you are relying on the AINS alone. That’s fine at 30,000 feet over the Pacific, but not at 10,000 feet near Ross Island.
Brian Abraham:
If the alleged error is the decision to go down, then doesn’t that remove the whiteout issue? There was no sector whiteout at 18000 feet. Whiteout only became an issue once under the cloudbase. So the decision to go down would have been an error in any area, polar or tropical, with 13000 feet worth of high ground around.
So I’d be “tooling around” with Prospector at 18000 feet.
I’ve had another read through the whole 30 minutes of the transcript. There is a definite impression that the captain was anxious to get the radar fix. Note that he gets on the blower himself at about 40 miles out, which was the radar range he had been given by ATC.