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The purpose of this SAE Aerospace Recommended Practice (ARP) is to provide a practical definition of external hydraulic fluid leakage exhibited by landing gear shock absorbers/struts. The definition will outline normal (acceptable weepage) and excessive leakage (unacceptable leakage) of shock absorbers/struts that is measurable. The definition of leakage is applicable to new gear assemblies, refurbished/remanufactured (overhauled) shock absorbers/struts, leakage of shock absorbers/struts encountered during acceptance flights, newly delivered and in-service aircraft. This ARP is intended to provide guidelines for acceptable leakage of landing gear shock absorbers/struts between the ambient temperatures of -65 °F (-54 °C) and 130 °F (54 °C) and to outline the procedure for measuring such leakage. The specific limits that are applied to any particular aircraft shall be adjusted by the aircraft manufacturer before inclusion in the applicable maintenance manual.

This SAE Aerospace Recommended Practice (ARP) provides guidance on the definition, development, and establishing a LGIP.

The scope of this document is to discuss the differences between electromechanical and proximity position sensing devices (sensor or switch) when used on landing gear. It also contains information which may be helpful when applying either type of technology after the selection has been made. The purpose is to help the designer make better choices when selecting a position-sensing device. Once that choice has been made, this document includes information to improve the reliability of new or current designs. It is not intended to replace recommendations from sensor manufacturers or actual experience, but to provide a set of general guidelines based on historic infromation of what is being used.

The intent of this SAE Aerospace Information Report (AIR) is to document the design requirements and approaches for the crashworthy design of aircraft landing gear. This document covers the field of commercial and military airplanes and helicopters. This summary of crashworthy landing gear design requirements and approaches may be used as a reference for future aircraft.

This document establishes a procedure for disposition of landing gear components that have been involved in accidents/incidents. The recommendations in this document apply to components made of ferrous and non-ferrous alloys. The recommendations in this document do not apply to components made of non metallic composite materials.

The scope of this document is to discuss the differences between electromechanical and proximity position sensing devices when used on landing gears. It also contains information, which may be helpful, when applying either type of technology after the selection has been made. The purpose is to help the designer make better choices when selecting a position-sensing device. Once that choice has been made, this document includes information to improve the reliability of new or current designs. It is not intended to replace recommendations from sensor manufacturers or actual experience, but to provide a set of general guidelines.

This document examines the most important considerations relative to the use of proximity sensing systems for applications on aircraft landing gear. In general, the recommendations included are applicable to other demanding aircraft sensor installations where the environment is equally severe.

This information report provides general guidance for the design considerations, qualification in endurance, strength and fatigue of landing gear using composite components as principle structural elements. The information discussed herein includes the development and evaluation of design data considering: the potential for imbedded manufacturing defects, manufacturing process variations, the component operating environment, potential damage threats in service, rework and overhaul, and inspection processes. This AIR mainly discusses the use of thick composites for landing gear structural components. Considerations and recommendations provided in this AIR may therefore differ greatly from considerations and recommendations found in widely accepted composite design references such as CMH-17 and Advisory Circulars such as AC 20-107(B).

This SAE Aerospace Information Report (AIR) provides guidelines for the development of landing gear fatigue spectra for the purpose of designing and certification testing of Part 25 landing gear. Many of the recommendations herein are generalizations based on data obtained from a wide range of landing gears. The aircraft manufacturer or the landing gear supplier is encouraged to use data more specific to their particular undercarriage whenever possible.

This Aerospace Information Report (AIR) will examine considerations relative to the use of mechanical switches on aircraft landing gear, and present "lessons learned" during the period that these devices have been used.

This recommended practice covers the fixed structure, or independent energy absorbing system affixed to the airframe to afford protection to the control surfaces, engine and other portions during ground handling, take-off and landing.

This SAE Aerospace Recommended Practice (ARP) applies to fatigue testing of landing gear and landing gear components.

This document outlines the most common repairs used on landing gear components. It is not the intention of this AIR to replace Overhaul/Component Maintenance or Technical Order Manuals, but it can serve as a guide into their preparation. This document may also be used as a template to develop an MRB (Material Review Board) plan. The recommendations in this document apply to components made of metallic alloys. These recommendations are intended for new manufactured components as well as for overhauled components. The extent of repair allowed for new components as opposed to in-service components is left to the cognizant engineering authorities. Reference could be made to this document when justifying repairs on landing gears. For repairs outside the scope of this document, a detailed justification is necessary. It must be understood that all the repairs listed in this document are not to be applied without the involvement of the cognizant engineer.

This SAE Aerospace Recommended Practice (ARP) applies to landing gear structures and mechanisms (excluding wheels, tires, and brakes and other landing gear systems) for all types and models of civil and military aircraft. All axles, wheel forks, links, arms, mechanical and gas/oil shock struts, downlock and uplock assemblies, braces, trunnion beams, and truck beams etc., that sustain loads originating at the ground, and that are not integral parts of the airframe structure, should be designed and validated in accordance with this document. Hydraulic actuators (retraction, main and nose gear steering, positioning, damping, etc.) should also be included in this coverage. System level, non-structural components such as retraction/extension valves, controllers, secondary structure and mechanisms in the airframe (e.g., manual release mechanisms, slaved doors) as well as equipment that is located in the cockpit are not addressed in this ARP.

This document provides recommended practices for the design, development, and verification testing of aircraft nosewheel steering (NWS) systems.

This SAE Aerospace Recommended Practice (ARP) applies to fatigue testing of landing gear and landing gear components.

This recommended practice covers the fixed structure, or independent energy absorbing system affixed to the airframe to afford protection to the control surfaces, engine and other portions during ground handling, take-off and landing.

This ARP applies to all types and models of civil aircraft for landing gear structure and mechanism excepting wheels, tires and brakes. All axles, wheel forks, axle beams, links, arms, mechanical and air-oil energy absorbers, braces, lock assemblies, trunnion beams, etc., that sustain loads originating at the ground and that are not integral parts of the airframe structure shall be in accordance with this practice.

This document establishes a procedure for disposition of landing gear components that have been involved in accidents/incidents. The recommendations in this document apply to components made of ferrous and non-ferrous alloys.

Verification of landing gear design strength is accomplished by dynamic and static test programs. This is essentially a verification of the analytical procedures used to design the gear. An industry survey was recently conducted to determine just what analysis and testing are currently being applied to landing gear. Timing in relation to first flight of new aircraft was also questioned. Opinions were solicited from designers of the following categories and/or types of aircraft: a Military - Large Land Based (Bomber) b Military - Small Land Based (Fighter) c Military - Carrier Based (Navy) d Military - Helicopter (Large) e Military - Helicopter (Small-attack) f Commercial - Large (Airliner) g Commercial - Small (Business) h USAF (WPAFB) - Recommendations It is the objective of this AIR to present a summary of these responses. It is hoped that this summary will be useful to designers as a guide and/or check list in establishing criteria for landing gear analysis and test.