STC SA420SW

Install Dual Collins FD-108 flight director system replacing Collins ID -105 Flight Director System having dual instrumentation with single steering computer

Current Reissued Aircraft Large Airplane Rev 06/26/1969 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 (4)

4A21 The Boeing Company · 707-100B Long Body
4A21 The Boeing Company · 707-100B Short Body
4A21 The Boeing Company · 707-200
4A28 The Boeing Company · 720 Series

Certification basis — 14 CFR

Part 21

Specific sections

§ 21.47
§ 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 ↗