FAA · Supplemental Type Certificate
STC ST173CH
Installation of cockpit blower system. (DC-3 SERIES -TP67 turbine conversion per STC SA 4840NM)
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 (1)
The STC PDF on drs.faa.gov is the authoritative document — it lists installation instructions, ICA requirements, and any limitations. Open PDF ↗