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Atlas / STC / SH338NW

FAA · Supplemental Type Certificate

STC SH338NW

Installation of transmission oil cooling system on the Allison250-C20 turbine powered Hiller UH-12D rotorcraft. (UH-12D (ARMY UH-23D modified per STC SH177WE)

Current Reissued Aircraft Rotorcraft Rev 08/19/2005 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 (1)

Certification basis — 14 CFR

Specific sections

  • Sec. 111
  • Sec. 113
  • Sec. 115
  • Sec. 117
  • Sec. 119
  • Sec. 120
  • § 21.47

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