Modification of main rotor blade part number 61170-20201 in accordance with Master Drawing List RR 9633-08, Revision A, dated September 17, 2002, or later FAA approved revision. Retirement life for the modified main rotor blade, part number RR-61170-20201 is 21,200 total time in service. View PDF on drs.faa.gov ↗

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