F.1.13 Rollover Protection Envelope
The Primary Structure plus a plane from the top of the Main Hoop to the top of the Front Hoop, plus a plane from the top of the Main Hoop to the rearmost Triangulated structural tube, or monocoque equivalent. * If there are no Triangulated Structural members aft of the Main Hoop, the Rollover Protection Envelope ends at the rear plane of the Main Hoop
Explanation
The Rollover Protection Envelope is an extension of the Primary Structure. Rollover Protection includes the Primary Structure, plus two tangent planes. The first tangent plane connects the top of the Main Hoop to the top of the Front Hoop, and the second tangent plane connects the top of the Front Hoop to the rearmost triangulated structure, in this case it is Rear Impact Protection for the EV system.