Rananim,
Why is it not a simple controlled flight into terrain??
The aircraft was completely serviceable, and it was flown into a mountain.
This was the company order for the descent, and as a copy of it was found in the cockpit after the accident the crew must have been aware of its requirements.
Delete all reference in briefing dated 23/10/79. Note that the only let-down procedure available is VMC below FL160 (16,000ft) to 6000ft as follows.
1. Vis 20 km plus.
2. No snow showers in area.
3. Avoid Mt Erebus area by operating in an arc from 120 Grid through 360 Grid to 270 Grid from McMurdo field within 20 nm of TACAN CH29.
4. Descent to be coordinated with local radar control as they may have other traffic in the area.
You will note that it states THE ONLY LET DOWN PROCEDURE AVAILABLE.
The weather at Mc Murdo was well below this minima, so does that authorize the crew to invent their own let down procedure?? The sector whiteout explains why they flew into Erebus without seeing it, but does not explain what they were doing down there.
Prospector