Final Publications Archives - Page 50 of 195

FAA AC 25.1309-1B, System Design and Analysis

This advisory circular (AC) describes acceptable means, but not the only means, for showing compliance with the requirements of title 14, Code of Federal Regulations (14 CFR) 25.1309, Equipment, systems, and installations. These means are intended to provide guidance to supplement the engineering and operational judgment that form the basis of any showing of compliance.

Revision B of this AC contains new guidance based on proposed rule changes to § 25.1309. You can find those proposed changes in Notice of Proposed Rulemaking (NPRM) titled System Safety Assessments, Notice No. 23-04. That NPRM was published in the Federal Register on December 8, 2022 (87 FR 75424) and is also available at http://www.regulations.gov/ under Docket No. FAA-2022-1544. The FAA recommends that you refer to that NPRM before reading and commenting on this proposed AC.

FAA AC 25.933-1, Unwanted In-Flight Thrust Reversal of Turbojet Thrust Reversers

This advisory circular (AC) describes various acceptable means for showing compliance with the requirements of paragraphs (a)(1) and (2) of title 14, Code of Federal Regulations (14 CFR) 25.933, Reversing systems, as they apply to unwanted in-flight turbojet thrust reversals on transport category airplanes.

This AC would provide guidance for changes to § 25.933 proposed in the Notice of Proposed Rulemaking (NPRM) titled System Safety Assessments, Notice No. 23-04. That NPRM was published in the Federal Register on December 8, 2022 (87 FR 75424) and is also available at http://www.regulations.gov/ under Docket No. FAA-2022-1544. The FAA recommends that you refer to that NPRM before reading and commenting on this proposed AC.

AC 25.671-1, Control Systems—General

This advisory circular (AC) describes acceptable means for showing compliance with the requirements of title 14, Code of Federal Regulations (14 CFR) 25.671, Control Systems—General. These means are intended to provide guidance to supplement the engineering and operational judgment that forms the basis of any demonstration of compliance. Section 25.671 applies to all flight control system installations (including primary, secondary, trim, lift, drag, feel, and load alleviation and stability augmentation systems, and other systems or functions implemented through or supporting the flight control components) regardless of implementation technique (manual, powered, fly by wire, or other means). This AC provides guidance on means of compliance with regulatory provisions that address operation of the control systems (§ 25.671(a)), design of the control system assembly (§ 25.671(b)), failures of the control system (§ 25.671(c)), control system design in the event all engines fail (§ 25.671(d)), control authority awareness (§ 25.671(e)), and flight control system modes of operation (§ 25.671(f)).

This AC would provide guidance for changes to § 25.671 proposed in the Notice of Proposed Rulemaking (NPRM) titled System Safety Assessments, Notice No. 23-04. That NPRM was published in the Federal Register on December 8, 2022 (87 FR 75424) and is also available at http://www.regulations.gov/ under Docket No. FAA-2022-1544. The FAA recommends that you refer to that NPRM before reading and commenting on this proposed AC.

Draft FAA AC 25.629-1C, Aeroelastic Stability Substantiation of Transport Category Airplanes

This advisory circular (AC) provides general guidance for acceptable means, but not the only means, of demonstrating compliance with those provisions of title 14, Code of Federal Regulations (14 CFR) 25.629, Aeroelastic stability requirements, and other part 25 regulations related to aeroelastic instabilities of flutter, divergence, and control reversal. Revision C would incorporate changes to portions of this AC affected by the System Safety Assessments proposed rulemaking, Notice No. FAA-2022-1544, which would revise the failure criteria specified in §§ 25.629, 25.671, and 25.1309.