Jump plane modifications that are not specifically described in the Aircraft Flight Manual must be accomplished by FAA issuance of either a Supplemental Type Certificate (STC) or a Field Approval. For $100 ($200 for non-members), USPA sells STCs for jump conversions of original and early model Cessna 170, 172, 180, and 182 aircraft. These STCs accommodate the removal of the door, not an in-flight door. E-mail the Government Relations department at govrelations@uspa.org or call (540) 604-9740.