Sec. 29.619 - Special factors.
(a) The special factors prescribed in §§29.621 through 29.625 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 of the rotorcraft to which §§29.621 through 29.625 apply, the factor of safety prescribed in §29.303 must be multiplied by a special factor equal to --
(1) The applicable special factors prescribed in §§29.621 through 29.625; 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.