Originally Posted by AMPAN
If he thought that the visual problem was overcome because he had his AINS track, then his mistake was lumping visual rules in with instrument rules, taking bits from both. He couldn't have his cake and eat it too. If it wasn't VMC below the cloud, that was the end of it. If he wanted to go down there, he had to do it on instruments.
The operator I fly for descend both VMC both IMC using LNAV/VNAV coupled to the guidance. When flying visually or even VFR (which we occasionally do though not in Antactica) we still use the Area nav to manage the navigation, though we are flying visually and avoiding the rocks by looking out of the window. No lumping together of visual or instrument rules there, just good utilization of what the aircraft offers us. As I suspect Jim Collins was doing.