Advisory Circulars

Explains how to compute airport capacity and aircraft delay for airport planning and design. Consolidated file contains Changes 1 and 2.

Note: Portions of this AC are under review for update. Please contact the National Planning and Environmental Division for assistance.

Because of the size of this document, it is available as one large file (see Complete) or as several smaller files (see Parts 1-4).

Provides a means whereby air taxi operators may submit a maintenance program to comply with FAR Part 135, Section 135.91.

Establishes an acceptable means, but not the only means, of obtaining operational approval of an airborne wind shear alerting and flight guidance system. It describes acceptable simulation test criteria, wind field modeling data, and minimum performance parameters for evaluating candidate systems.

Sets forth an equivalent means of complying with the provisions of Part 25 of the Federal Aviation Regulations (FAR) pertaining to the certification requirements of active flight controls. The procedures set forth herein apply to load alleviation systems (SAS), and flutter suppression systems (FSS). These procedures provide compliance with Part 25 under the equivalent safety provisions of Section 21.21(b)(1) in addition to compliance with the applicable sections of Part 25.

Provides air carriers, freight forwarders, and shippers with sources of regulatory and training information and provides office locations and telephone numbers where technical assistance may be obtained dealing with the provisions of the appropriate regulations concerning the transportation by air of commodities which have been designated as regulated hazardous materials.

Provides guidance to the operators of ultralights in the United States. It discusses the elements, which make up the definition of ultralight vehicles for the purposes of operating under Federal Aviation Regulation (FAR) Part 103. It also discusses when an ultralight must be operated as an aircraft under the regulations applicable to certificated aircraft.

Provides background information on G-forces, their effect on the human body and their role in safe flying, and offers suggestions for avoiding problems caused by acceleration encountered in aerobatic maneuvers.

Recommends several actions that the user can take to alleviate problems of frequency congestion in the 190-535 kHz frequency range.

Provides information relating to the use of alternate grades of gasoline when grade 80/87 aviation is not available and the resultant effects of the use of the alternate fuels which have higher TEL (tetraethyl lead) content. Suggestions are offered as acceptable means of avoiding engine operating difficulties when using alternate fuels. This circular also provides suggestions for added safety in the use of automotive gasoline in those aircraft engines and aircraft covered by Supplemental Type Certificates (STCs).

Provides recommendations, but is not the only means, that may be used by glider pilots who desire to transition into sailplanes or gliders with self-launching capability.

Sets forth acceptable conditions under which automobile gasoline (autogas) may be used in restricted category agricultural aircraft powered by Pratt and Whitney R-985 and R-1340 radial engines, and being used in agricultural operations under Federal Aviation Regulations Part 137.

Provides information and guidance concerning compliance with Part 23 for self-locking nuts used on bolts subject to rotation in operation.

Provides information and guidance to individuals who come in contact with depleted uranium contained in aircraft control surfaces during accident investigations.

Sets forth a specific method of compliance with the requirements of section 25.1455 of the FAR pertaining to draining of fluids through drain masts when the fluids are subject to freezing. This method is designed to verify that draining fluids will not accumulate as ice in sufficient quantity to be hazardous. Is for guidance purposes and to set forth one method of compliance that has been found acceptable.

Modifies and updates the flight information available to pilots as a result of changes in the basic Airmen Information Manual format.

Describes a range of impact trauma which may be used to establish bases for acceptance levels or performance criteria in the evaluation of occupant survivability characteristics in civil aircraft.

Provides revised guidelines on the marking of aircraft powerplant instruments and electronic displays (cathode ray tubes, etc.). These guidelines offer acceptable, but not exclusive, methods of compliance with the powerplant instrument color marking requirements.

Describes a method of demonstrating compliance with the requirements of the FAR concerning the ingestion of water from the runway/taxiway surface into the airspeed system, the engine, and essential auxiliary power unit air inlet ducts of turbine engine power unit air inlet ducts of turbine engine powered airplanes.

Provides guidance material for acceptable means of demonstrating compliance with the requirements of Part 33 of the Federal Aviation Regulations (FAR) relative to surge and stall characteristics and thrust response of turbine engines. These guidelines do not constitute a regulation and are therefore not mandatory.

Familiarize the helicopter pilot/instructor and pilot school personnel of the hazards associated with dynamic rollover.

Provides estimates of noise levels or measured noise levels from airplanes not certificated to FAR Part 36.

Provides guidelines for the evaluation of turbine engine (turbojet, turboprop, and turboshaft) operating characteristics for subsonic transport category airplanes.