14 CFR PART 21 SUBPART O—TECHNICAL STANDARD ORDERS (TSO) - Know To This Aeronautical Airplane Engineering Knowledge

A Technical Standard Order (TSO) is issued by the Administrator and is a minimum performance standard for specified articles, such as parachutes. It is important that the parachute rigger understand the TSO process and the various levels of TSO approval under which parachutes are manufactured. Every parachute rigger should read and become familiar with the technical standard orders for parachutes, the 23 series (C23b, C23c, C23d). This is important to the parachute rigger in determining certification compatibility when he/she is assembling approved components.