2020-02741

Document Headings Document headings vary by document type but may contain the following: • the agency or agencies that issued and signed a document • the number of the CFR title and the number of each part the document amends, proposes to amend, or is directly related to • the agency docket number / agency internal file number • the RIN which identifies each regulatory action listed in the Unified Agenda of Federal Regulatory and Deregulatory Actions See the Document Drafting Handbook for more details. Department of Transportation Federal Aviation Administration • 14 CFR Part 27 • [Docket No. FAA-2019-0546; Notice No. 27-048-SC] AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final special conditions. SUMMARY: These special conditions are issued for the Bell Helicopter Textron Canada Limited (BHTCL) Bell Model 505 helicopter. This helicopter as modified by S-TEC will have a novel or unusual design feature associated with installation of the autopilot and stability augmentation system (AP/SAS system). The applicable airworthiness regulations do not contain adequate or appropriate safety standards for this design feature. These special conditions contain the additional safety standards that the Administrator considers necessary to establish a level of safety equivalent to that established by the existing airworthiness standards. DATES: These special conditions are effective February 19, 2020. FOR FURTHER INFORMATION CONTACT: Andy Shaw, Aerospace Engineer, FAA, Rotorcraft Standards Branch, Policy and Innovation Division, 10101 Hillwood Pkwy, Fort Worth, TX 76177; telephone (817) 222-5384; email Andy.Shaw@faa.gov. SUPPLEMENTARY INFORMATION: Background On January 21, 2019, S-TEC applied for a supplemental type certificate (STC) to install an AP/SAS system on the Bell Model 505 helicopter. The Bell Model 505 helicopter is a 14 CFR part 27 normal category, single turbine engine, conventional helicopter designed for civil operation. This helicopter model is capable of carrying up to four passengers with one pilot and has a maximum gross weight of up to 4,475 pounds (external loading). The major design features include a 2-blade main rotor, an anti-torque tail rotor system, a skid landing gear, and a visual flight rule basic avionics configuration. S-TEC proposes to modify this model helicopter by installing an AP/SAS system. The AP/SAS system provides attitude stabilization in two or three axes (pitch and roll with optional yaw) as well as higher-level autopilot functions such as altitude hold, heading command and navigation tracking. However, the possible failure conditions for this system, and their effect on the continued safe flight and landing of the helicopter, are more severe than those envisioned by the present rules. The effect on safety is not adequately covered under 14 CFR 27.1309 for the application of new technology and new application of standard technology. Specifically, the present provisions of § 27.1309(c) do not adequately address the safety requirements for systems whose failures could result in catastrophic or hazardous/severe-major failure conditions, or for complex systems whose failures could result in major failure conditions. The current regulations are inadequate because when § 27.1309(c) was promulgated, it was not envisioned that a normal category rotorcraft would use systems that are complex or whose failure could result in “catastrophic” or “hazardous/severe-major” effects on the rotorcraft. This is particularly true with the application of new technology, new application of standard technology, or other applications not envisioned by the rule that affect safety. Possible failure modes exhibited by the S-TEC AP/SAS system could result in a catastrophic event. Type Certification Basis Under 14 CFR 21.101, S-TEC must show that the Bell Model 505 helicopter, as modified by the installed AP/SAS, continues to meet the applicable regulations incorporated by reference in the Type Certificate Nu…

Fonte: Federal Register (federalregister.gov). Texto original em inglês. Conteúdo sanitizado por segurança.