30 CFR § 7.7
Quality assurance.
Applicants granted an approval or an extension of approval under this part
shall--
(a) Inspect or test, or both, the critical characteristics in
accordance with the appropriate subpart of this part;
(b) Unless otherwise specified in the subparts, calibrate instruments
used for the inspection and testing of critical characteristics at least as
frequently as, and according to, the instrument manufacturer's
specifications, using calibration standards traceable to those set by the
National Bureau of Standards, U.S. Department of Commerce or other nationally
recognized standards and use instruments accurate to at least one significant
figure beyond the desired accuracy.
(c) Control production documentation so that the product is
manufactured as approved;
(d) Immediately report to the MSHA Approval and Certification Center,
any knowledge of a product distributed with critical characteristics not in
accordance with the approval specifications.
[60 FR 33719, June 29, 1995]