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This SAE Aerospace Information Report (AIR) advises that some of the chemicals being used to disinfect, de-ice, and clean airplanes can cause corrosion and/or degradation of landing gear components. Landing gear equipment includes shock struts, braces, actuators, wheels, brakes, tires, and electrical components. Some of the chemicals that have been recognized as potentially injurious are identified and recommendations for mitigating damage are presented.

This SAE Aerospace Information Report (AIR) advises that some of the chemicals being used to disinfect, de-ice, and clean airplanes can cause corrosion and/or degradation of landing gear components. Landing gear equipment includes shock struts, braces, actuators, wheels, brakes, tires, and electrical components. Some of the chemicals that have been recognized as potentially injurious are identified and recommendations for mitigating damage are presented.

CPs are a process that is executed on a critical landing gear (or undercarriage) part, assembly or equipment that if performed incorrectly or omitted would cause: An operational failure of the aircraft; or An unacceptable risk of injury This document identifies CPs that have either caused operational failure or that can be reasonably expected to cause operational failures based on experience. Note that in the interest of brevity, that this document is not intended to be a definitive listing, only an introduction and a consideration of common processes.

This SAE Aerospace Information Report (AIR) covers the field of civilian, commercial and military airplanes and helicopters. This summary of tail bumper design approaches may be used by design personnel as a reference and guide for future airplanes and helicopters that require tail bumpers. Those described herein will consist of simple rub strips, structural loops with a wear surface for runway contact, retractable installations with replaceable shock absorbers and wear surfaces and complicated retractable tail landing gears with shock strut, wheels and tires. The information will be presented as a general description of the installation, its components and their functions.

This SAE Aerospace Information Report (AIR) covers the field of civilian, commercial and military airplanes and helicopters. This summary of tail bumper design approaches may be used by design personnel as a reference and guide for future airplanes and helicopters that require tail bumpers. Those described herein will consist of simple rub strips, structural loops with a wear surface for runway contact, retractable installations with replaceable shock absorbers and wear surfaces and complicated retractable tail landing gears with shock strut, wheels and tires. The information will be presented as a general description of the installation, its components and their functions.

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.

Steel alloys, such as AF1410 (AMS 6527, UNS K92571) and AerMet 100 (AMS 6532), have been developed which have improved Fracture Toughness characteristics compared to the current landing gear steel alloy, 300M (AMS 6419 and AMS 6257, MIL-S-8844, UNS K44220). The 300M steel is the most widely used material in current landing gear designs. It has been successfully used in thousands of applications. The use of the 300M material necessitates a safe life design criterion where components are retired after one-fourth to one-sixth the laboratory test life. This criterion was established in part due to the relatively low fracture toughness of low-alloy steel in the 260 to 300 ksi strength range. The high fracture tough alloys give comparable strength levels with an increase in fracture toughness and better resistance to stress corrosion cracking. These alloys may make possible the consideration of new procedures for operation, maintenance, and inspection.

Steel alloys, such as AF1410 (AMS 6527, UNS K92571) and AerMet 100 (AMS 6532), have been developed which have improved Fracture Toughness characteristics compared to the current landing gear steel alloy, 300M (AMS 6419 and AMS 6257, MIL-S-8844, UNS K44220). The 300M steel is the most widely used material in current landing gear designs. It has been successfully used in thousands of applications. The use of the 300M material necessitates a safe life design criterion where components are retired after on-fourth to one-sixth the laboratory test life. This criterion was established in part due to the relative low fracture toughness of low-alloy steel in the 260 to 300 ksi strength range. The high fracture tough alloys give comparable strength levels with an increase in fracture toughness and better resistance to stress corrosion cracking. These alloys may make possible the consideration of new procedures for operation, maintenance, and inspection.

This SAE Aerospace Recommended Practice (ARP) provides recommendations on cavity design, the installation of elastomer type spare seals in these cavities, and information surrounding elastomer material properties after contact with typical shock absorber hydraulic fluid(s) or grease. This ARP is primarily concerned with the use of spare seals on shock absorbers where only a single dynamic seal is fitted and in contact with the slider/shock absorber piston at any one time. These shock absorbers typically have a spare (dynamic) seal gland located on the outer diameter of the lower seal carrier. This spare seal gland is intended to house a spare elastomer contact seal. Split Polytetrafluoroethylene (PTFE) backup rings can also be installed in the spare seal cavity. During operation, if the fitted dynamic shock absorber standard seal begins to fail/leak, then the aircraft can be jacked up, allowing the lower gland nut of the shock absorber to be dropped down.

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

Recent field experience has indicated significant problems with some types of wire and cable as routed on aircraft landing gear. This Aerospace Information Report (AIR) is intended to identify environmental concerns the designer must consider, materials that appear to be most suitable for use in these areas, routing, clamping, and other protection techniques that are appropriate in these applications.

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 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. Refer to the applicable component drawings and specifications for surface finish, thickness, and repair processing requirements. This document may also be used as a guide to develop an MRB (Material Review Board) plan. The repairs in this document apply to components made of metallic alloys. These repairs are intended for new manufactured components and overhauled components, including original equipment manufacturer (OEM)/depot and in-service repairs. 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.

This SAE Aerospace Standard (AS) covers an alternate gland design for the installation of scraper/ wiper rings in the lower end of landing gear shock struts for the purpose of contaminant exclusion. The defined scraper gland covered by this document, as shown in Table 1, is a variant of AS4716, the accepted gland standard for AS568, O-ring packing seals. Piston rod diameters, gland internal diameters, groove sidewall angles and the surface finish are all defined by AS4716, but the gland outer retaining wall diameter is changed. The traditional scraper design installed into the glands detailed in Table 1 typically utilize components made from PTFE, urethane, or nitrile materials. These scraper designs, while still acceptable, must be reviewed in consideration to deicing, cleaners and disinfectant fluids applied to or in contact with the landing gear, as the materials of construction for the installed scrapers may not be compatible to these fluids.

This SAE Aerospace Standard (AS) covers an alternate gland design for the installation of scraper/wiper rings in the lower end of landing gear shock struts for the purpose of contaminant exclusion. The defined scraper gland covered by this document, as shown in Table 1, is a variant of AS4716, the accepted gland standard for MS28775, O-ring packing seals. Piston diameters, gland internal diameters, groove sidewall angles and the surface finish are all defined by AS4716, but the gland outer retaining wall diameter is changed. AS4088 is similar to this document, but was developed by SAE A-6 for flight control and general-purpose cylinders. It differs from this document primarily by the clearance between the rod (piston) and outer gland wall. Since landing gears are more susceptible to dirt contamination, the additional clearance provides a larger path to allow excessive dirt accumulation to exit the gland.

This SAE Aerospace Standard (AS) covers an alternate gland design for the installation of scraper/wiper rings in the lower end of landing gear shock struts for the purpose of contaminant exclusion. The defined scraper gland covered by this document, as shown in Table 1, is a variant of AS4716, the accepted gland standard for MS28775, O-ring packing seals. Piston rod diameters, gland internal diameters, groove sidewall angles and the surface finish are all defined by AS4716, but the gland outer retaining wall diameter is changed. The traditional scraper design installed into the glands detailed in Table 1 typically utilize components made from urethane or nitrile materials. These scraper designs, while still acceptable, must be reviewed in consideration to deicing, cleaners and disinfectant fluids applied to or in contact with the landing gear, as the materials of construction for the installed scrapers may not be compatible to these fluids.

This document defines the criteria used for the selection of landing gear shock strut upper and lower bearings.

This document defines the criteria used for the selection of landing gear shock strut upper and lower bearings (see Figure 1).

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

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