Parachute Materials, Components, and Hardware
What this domain tests
This domain tests whether you can identify parachute fabrics, lines, threads, tapes, and hardware, and whether you understand why approved material matters. Exam items often ask you to choose a replacement part or reject a substitution.
Core rules and concepts
- Fabrics. Canopies are commonly made from MIL-SPEC nylon, often ripstop. Fabric weight, weave, porosity, and finish affect strength and opening. UV exposure, acid, mildew, and abrasion reduce serviceability; a fabric can look clean and still fail a porosity or strength requirement.
- Suspension lines. Line material may be nylon, Dacron, Spectra, Vectran, or another approved fiber. Strength alone is not equivalence: elongation, modulus, diameter, and line trim affect opening shock, canopy trim, and load distribution. Replace lines with the material and size specified in approved data.
- Thread and tape. Bonded nylon thread is common in parachute construction. Thread size, needle size, and stitch balance must match the specification. Webbing and tape carry harness and container loads and must not be replaced with hardware-store equivalents.
- Hardware. Connector links, three-ring releases, ripcords, pilot chutes, spring assemblies, and AADs are load- or function-critical. Inspect for corrosion, cracks, deformation, sharp edges, and correct closure. A connector link that is the wrong size or not fully closed is a reject.
Worked example
A rigger finds a damaged suspension line. The original is nylon; a replacement of the same diameter is available in Spectra, which has higher tensile strength. Is the stronger line acceptable? No. Higher strength does not reproduce the original elongation under load. A low-stretch line can change opening characteristics and canopy trim, and it may overload attachment points. The correct action is to use the line material, size, and construction called out in the parachute’s approved data, then verify line trim and attachment.
Traps that cost marks
- “Stronger is better” substitutions that ignore elongation and trim.
- Matching only diameter or breaking strength instead of the approved part number.
- Passing hardware that is corroded, deformed, or fitted with a nonstandard pin or keeper.
- Assuming clean fabric is airworthy without checking porosity, stains, or UV damage.