The purpose of this memorandum is to eliminate confusion in current guidance material related
to Unmanned Aircraft Systems (UAS) maintenance. This memorandum clarifies two areas: (1)
the issuance of appropriate maintenance operating limitations (#34 through #38) in FAA Order
8130.34D, Appendix A, and (2) maintenance requirements for UAS conducting IFR operations.
This memorandum authorizes the following deviation(s) to FAA Order 8130.34D, Appendix A,
Operating Limitations (34) through (38).

This AC provides information
and guidelines to Title 14 of the Code of Federal Regulations (14 CFR) part 135
air carriers/operators to aid in the development of a Second in Command Professional
Development Program (SIC PDP) which meets the requirements of part 135, § 135.99(c).
This program allows a pilot employed by the part 135 air carrier/operator and serving
as an assigned second in command (SIC) in a multiengine airplane or single-engine,
turbine-powered airplane to log SIC flight time during operations that do not require
a second pilot.

This advisory circular (AC) sets forth an acceptable means, but not the only means, for
demonstrating compliance with title 14 of the Code of Federal Regulations (14 CFR) §§ 23.562,
25.562, 27.562, and 29.562, as well as Technical Standard Order (TSO) TSO-C127a, and
TSO-C127b. This AC includes guidance for certifying seats by computer modeling analysis
techniques that are validated by dynamic tests. This AC defines the acceptable applications,
limitations, validation processes, and minimum documentation requirements involved when
substantiation by computer modeling is used to support a seat certification program.
If you have any suggestions for improvements or changes, you may use the Advisory Circular
Feedback form at the end of this AC.