1. PURPOSE OF THIS ADVISORY CIRCULAR (AC). The intent of this AC is to facilitate
operations using Automatic Dependent Surveillance-Broadcast (ADS-B) technology in
compliance with Title 14 of the Code of Federal Regulations (14 CFR) part 91, §§ 91.225
and 91.227. The appendices provide guidance on additional ADS-B Out and ADS-B In
operations that may be authorized by the Administrator.
2. PRINCIPAL CHANGES. This change adds Appendix F, which describes Interval
Management (IM) and provides guidance to operators seeking Federal Aviation Administration
(FAA) authorization to conduct IM operations. This change also updates references throughout
the AC.

This notice announces clarification to guidance in Federal Aviation
Administration (FAA) Order 8900.1, Volume 5, Chapter 9, Section 2, Airman Qualification
Requirements for Aircraft for Which the Operating Limitations Require an FAA-Issued
Authorization to Act as Pilot in Command.

The FAA proposes to amend
certain airworthiness regulations to
standardize the criteria for conducting
safety assessments for systems,
including flight controls and
powerplants, installed on transport
category airplanes. With this action, the
FAA seeks to reduce risk associated
with airplane accidents and incidents
that have occurred in service, and
reduce risk associated with new
technology in flight control systems.
The intended effect of this proposed
action is to improve aviation safety by
making system safety assessment (SSA)
certification requirements more
comprehensive and consistent.

The FAA proposes to revise certain regulations governing airman certification.

Specifically, the FAA Airman Certification Standards and Practical Test Standards are currently utilized as the testing standard for practical tests and proficiency checks for persons seeking or holding an airman certificate or rating. The FAA proposes to incorporate these Airman Certification Standards and Practical Test Standards by reference into the certification requirements for pilots, flight instructors, flight engineers, aircraft dispatchers, and parachute riggers.

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.

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.

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.

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.