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Atlas / STC / SA174GL

FAA · Supplemental Type Certificate

STC SA174GL

Modification of floor support between stations 228.5 and 353 to eliminate decrease in allowable floor loading with increased zero fuel weight.

Current Issued Aircraft Large Multi-Engine Rev 05/12/1977 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.

Certification basis — 14 CFR

Specific sections

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

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