Figure 5

The oculogravic effect. In the absence of any visible horizon and probably of any depth perception associated with the lights of the oil platform, the pilots were unaware of the increasing pitch-up attitude of the aircraft, which had reached 22° at the point of impact with the sea (angle α). They had unconsciously used the sensation of level flight generated by the helicopter dynamics as the frame of reference against which to judge their position relative to the platform. In consequence, they had perceived the platform to be below them.