At about 29:30, the main investigator states "Make sure the P-5 is set to manual." This is a control switch that controls air pressurization in the plane. You then see the switch being set to "MAN." Seconds later, the investigator leans forward to look at the control panel and states "It's hard to see." At this point, the P-5 control panel can be seen in the top right, and is set to "AUTO".