Brian Abraham.
"if as prospector maintains ALL FLIGHTS were to make their descent in the airline stipulated sector."
This from Maurice McGreal publication. "In relation to the criticism that the flight was planned over Mt Erebus, an active volcano, Bolt/Kennedy responded by saying that the duty of CAD was not to specify the route, that was for the airline, and CAD's job was to set the conditions that would ensure the safety of the flight.This clearly related to to the fact that the minimum safe altitude named in the Civil Aviation requirements for the flight was 16,000ft until the aircraft had passed over the McMurdo base station at which time it could descend to 6,000ft provided that the visibility was satisfactory, that is in visual conditions."
Because Air New Zealand took it upon themselves to treat these requirements as they did does not make them any less the mandatory requirements from the regulating body.