: Installation of Isolair Model 3900-110 Spray Tank System, in accordance with Federal Aviation Administration (FAA) approved Installation Instructions No. 3900-50, Pages 1 and 2, and Figures 1 through 7, Revision A, dated February 14, 1990, or later FAA-approved revisions and Drawing List Report No. 3980-110, Pages 1 through 4, dated February 14, 1990, or later FAA-approved revision. The modified helicopter must be maintained in accordance with Isolair Maintenance Instructions No. 3900-10, dated February 14, 1990, or later FAA-approved revision. Or optional installation of Isolair Model 3900-206 Spray System, in accordance with FAA-approved Installation Manual No. 39206INS Revision B, dated August 22, 2006, or later FAA-approved revision. Manufactured in accordance with Master Drawing List 3900-206, Revision IR, dated August 14, 2006 or later FAA-approved revision. The modified helicopter must be maintained in accordance with Isolair Document 3900ICA, Revision A, dated August 6, 2006, or later FAA-accepted revision. View PDF on drs.faa.gov ↗

The STC PDF is authoritative: installation instructions, ICA requirements and limitations.