AC 43.13-2B, Chapter 12, Section 1203 (a) (1-3) covers "Cargo Tiedown Devices." It says "Cargo tiedown devices may be assembled from webbing, nets, rope, cables, fittings, or other material that conforms to a FAA-PMA, TSO, NAS, AN, or MIL-SPEC standards[sic]". Note that the AC covers the raw materials, not the finished net.
No mention is made of an STC requirement.
The website of the manufacturer I cited says they make nets for "military, police, fire, government, aviation and marine applications."
I leave the rest of the exercise to the reader.
