(a) The head consists of the assembly shown in drawing 78051-61X, revision C, and conforms to each of the drawings subtended therein.

(b) When the head (Drawing number 78051-61X, titled “head assembly—complete,” dated March 28, 1997 (Revision C) with six axis neck transducer structural replacement (Drawing number 78051-383X, Revision P, titled “Neck Transducer Structural Replacement,” dated November 1, 1995) is dropped from a height of 14.8 inches in accordance with paragraph (c) of this section, the peak resultant accelerations at the location of the accelerometers mounted in the head in accordance with §572.36(c) shall not be less than 225g, and not more than 275g. The acceleration/time curve for the test shall be unimodal to the extent that oscillations occurring after the main acceleration pulse are less than ten percent (zero to peak) of the main pulse. The lateral acceleration vector shall not exceed 15g (zero to peak).

(c) Test procedure.

(1) Soak the head assembly in a test environment at any temperature between 66 degrees F to 78 degrees F and at a relative humidity from 10% to 70% for a period of at least four hours prior to its application in a test.

(2) Clean the head's skin surface and the surface of the impact plate with 1,1,1 Trichlorethane or equivalent.

(3) Suspend the head, as shown in Figure 19, so that the lowest point on the forehead is 0.5 inches below the lowest point on the dummy's nose when the midsagittal plane is vertical.

(4) Drop the head from the specified height by means that ensure instant release into a rigidly supported flat horizontal steel plate, which is 2 inches thick and 2 feet square. The plate shall have a clean, dry surface and any microfinish of not less than 8 microinches (rms) and not more than 80 microinches (rms).

(5) Allow at least 3 hours between successive tests on the same head.

[51 FR 26701, July 25, 1986, as amended at 62 FR 27514, May 20, 1997]