This AC provides an acceptable means, but
not the only means, to address operational use of Airborne Collision Avoidance Systems
(ACAS) in compliance with Title 14 of the Code of Federal Regulations (14 CFR)
part 91, 121, 125, 129, and 135 requirements. Title 14 CFR uses the term Collision
Avoidance System (CAS) or Traffic Alert and Collision Avoidance System (TCAS) to
describe what Title 49 of the Code of Federal Regulations (49 CFR) and the international
community has named ACAS. Other traffic awareness systems, such as Automatic
Dependent Surveillance-Broadcast (ADS-B) Traffic Advisory System (ATAS), are not
covered in this AC. CAS for unmanned aircraft, including Remain Well Clear (RWC)
and Detect and Avoid (DAA) systems, are not covered in this AC.

This notice announces the expiration of Exemption 12555 and removal of guidance in Federal Aviation Administration (FAA) Order 8900.1, Volume 3, Chapter 2, Section 3, Exemption 12555, and explains the action inspectors who have oversight of exemption holders must take. This notice contains information that is administrative in nature.

This notice announces the release of a new Letter of Authorization
(LOA) C381 for foreign General Aviation (GA) operators operating foreign-registered aircraft in
the United States under Title 14 of the Code of Federal Regulations (14 CFR) part 91. This
notice also announces a new section in Federal Aviation Administration (FAA) Order 8900.1
providing guidance for the issuance of LOA C381.

This final rule adopts permanent amendments and a Special Federal Aviation Regulation (SFAR) for a period of ten years to: facilitate the certification of powered-lift pilots, clarify operating rules applicable to operations involving a powered-lift, and finalize other amendments which are necessary to integrate powered-lift into the National Airspace System (NAS). In this final action, the FAA finalizes its alternate framework to stand-up initial groups of powered-lift pilots and flight instructors. Most notably, the FAA adopts alternate frameworks to facilitate the certification of pilots seeking qualifications in a powered-lift with single functioning flight controls and a single pilot station. In response to commenters, the FAA provides clarification for certain operating rules and adopts a performance-based approach to certain operating rules to enable powered-lift operations. In addition to finalizing provisions for powered-lift, this action also makes changes to practical tests in aircraft that require type ratings, including airplanes and helicopters, training center rotorcraft instructor eligibility, training and testing requirements, and training center use of rotorcraft in flight training.

This advisory circular (AC) is a summary of the current available data regarding identification
and treatment of corrosive attack on aircraft structures and engine materials. Corrosion
inspection frequency, corrosion identification, and especially corrosion treatment continues to be
the responsibility of the operator. These inspections should be accomplished per this AC, the
manufacturer’s recommendations, or the operator’s own maintenance program. The procedures
in this AC are an acceptable means, but not the only acceptable means, of corrosion treatment.
The information in this AC is applicable to aircraft for which the manufacturer has not published
corrosion control information. Where the airframe or engine manufacturer has published a
recommended corrosion inspection schedule and treatment program, the applicable program
must take precedence over the recommendation of this AC.