Section 27.619 - Special factors(a) The special factors prescribed in §§ 27.621 through 27.625 apply to each part of the structure whose strength is-(2) Likely to deteriorate in service before normal replacement; or(3) Subject to appreciable variability due to-(i) Uncertainties in manufacturing processes; or(ii) Uncertainties in inspection methods.(b) For each part to which §§ 27.621 through 27.625 apply, the factor of safety prescribed in § 27.303 must be multiplied by a special factor equal to- (1) The applicable special factors prescribed in §§ 27.621 through 27.625 ; or(2) Any other factor great enough to ensure that the probability of the part being understrength because of the uncertainties specified in paragraph (a) of this section is extremely remote.