(a) Head assembly. The head consists of the assembly designated as SA 106 010 on drawing No. SA 106C 001, sheet 2, and conforms to each drawing listed on SA 106C 001, sheet 8.

(b) Head assembly impact response requirements. When the head is impacted by a test probe conforming to §572.77(a)(1) at 7 feet per second (fps) according to the test procedure in paragraph (c) of this section, then the resultant head acceleration measured at the location of the accelerometer installed in the headform according to §577.77(b) is not less than 130g and not more than 160g.

(1) The recorded acceleration-time curve for this test is unimodal at or above the 50g level, and lies at or above that level for an interval not less than 1.0 and not more than 2.0 milliseconds.

(2) The lateral acceleration vector does not exceed 5g.

(c) Head test procedure. The test procedure for the head is as follows:

(1) Seat and orient the dummy on a seating surface having a back support as specified in §572.78(c), and adjust the joints of the limbs at any setting (between 1g and 2g) which just supports the limbs' weight when the limbs are extended horizontally and forward.

(2) Adjust the test probe so that its longitudinal center line is—

(i) At the forehead at the point of orthogonal intersection of the head midsagittal plane and the transverse plane which is perpendicular to the Z axis of the head as shown in Figure 40;

(ii) Located 2.7 ±0.1 inches below the top of the head measured along the Z axis, and;

(iii) Coincides within 2 degrees with the line made by the intersection of the horizontal and midsagittal planes passing through this point.

(3) Impact the head with the test probe so that at the moment of contact the probe's longitudinal center line falls within 2 degrees of a horizontal line in the dummy's midsagittal plane.

(4) Guide the test probe during impact so that there is no significant lateral, vertical, or rotational movement.

(5) Allow at least 60 minutes between successive head tests.