STC ST564SO

Installation of HF antenna and associated hardware and structural provisions for mounting HF tuning unit.

Current Issued Aircraft Large Multi-Engine Rev 11/19/1973 View PDF on drs.faa.gov ↗

What is an STC?

A Supplemental Type Certificate authorizes a major modification or alteration to an FAA-certificated aircraft. STCs are how operators legally install new avionics, change fuel systems, add floats, swap engines, etc. — every change beyond a minor modification needs one.

Applicable aircraft (2)

4A28 The Boeing Company · 720B
4A28 The Boeing Company · 720

Certification basis — 14 CFR

Part 21

Specific sections

§ 21.111
§ 21.113
§ 21.115
§ 21.117
§ 21.119
§ 21.120

The STC PDF on drs.faa.gov is the authoritative document — it lists installation instructions, ICA requirements, and any limitations. Open PDF ↗