14 C.F.R. Part 27
Airworthiness Standards: Normal Category Rotorcraft
AGeneralBFlightCStrength RequirementsDDesign and ConstructionEPowerplantFEquipmentGOperating Limitations and InformationAppendix A to Part 27Instructions for Continued AirworthinessAppendix B to Part 27Airworthiness Criteria for Helicopter Instrument FlightAppendix C to Part 27Criteria for Category AAppendix D to Part 27HIRF Environments and Equipment HIRF Test Levels27.1335Flight director systems.Repealed