5 2 . ▁ ▁In ▁ 1 9 5 5 , ▁the ▁Civil ▁Aer onaut ics ▁Board ▁separated ▁the ▁parts ▁authority ▁out ▁of ▁the ▁air worth iness ▁standards , ▁and ▁placed ▁it ▁in ▁a ▁more ▁general ▁location ▁so ▁that ▁one ▁standard ▁would ▁apply ▁to ▁replacement ▁and ▁modification ▁parts ▁for ▁all ▁different ▁forms ▁of ▁aircraft . ▁ ▁In ▁ 1 9 6 5 ▁C AR ▁ 1 . 5 5 ▁became ▁Federal ▁A viation ▁Reg ulation ▁section ▁ 2 1 . 3 0 3 . ▁ ▁The ▁ 1 9 6 5 ▁regul atory ▁change ▁also ▁im posed ▁specific ▁oblig ations ▁on ▁the ▁P MA ▁holder ▁related ▁to ▁the ▁Fab ric ation ▁In spe ction ▁System . ▁ ▁Am end ment ▁ 2 1 - 3 8 ▁of ▁Part ▁ 2 1 ▁was ▁published ▁May ▁ 2 6 , ▁ 1 9 7 2 . ▁ ▁This ▁was ▁the ▁next ▁rule ▁change ▁to ▁affect ▁P MA s . ▁ ▁This ▁rule ▁elimin ated ▁the ▁incorpor ation ▁by ▁reference ▁of ▁type ▁cert ification ▁requirements ▁in ▁favor ▁of ▁P MA - specific ▁data ▁submission ▁requirements . ▁ ▁This ▁change ▁established ▁the ▁separate ▁process ▁and ▁separate ▁requirements ▁for ▁data ▁that ▁must ▁be ▁submitted ▁by ▁an ▁applic ant ▁for ▁a ▁P MA ▁( p rior ▁to ▁this ▁there ▁was ▁no ▁explicit ▁distinction ▁between ▁the ▁application ▁data ▁requirements ▁for ▁type ▁certific ated ▁products ▁and ▁the ▁data ▁requirements ▁for ▁P MA ed ▁articles ). ▁ ▁The ▁aircraft ▁parts ▁after market ▁expanded ▁greatly ▁in ▁the ▁ 1 9 8 0 s