Damage on the facial roll ring rese

Damage on the facial roll ring resembled the shape of the triangular airplane support housing and the roll index that had been fixed to the instrument case. The relative positions of the damage resembling the triangular support and roll index were on the top and bottom of the ring, respectively, when it was placed at an inverted display of attitude. The face of the instrument was placed behind that of an exemplar instrument and, using the damage on the roll ring for alignment, the marks were within 2° of a wings-level inverted attitude.