Cessna 170 & C305A (USAF O‐1A) T3 Tailwheel Suspension System Installation Instructions

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ABI‐51525 Cessna 170 & C305A (USAF O‐1A) T3 Tailwheel Suspension System Installation Instructions Installation Instructions for Cessna 170 & C305A (USAF O-1A) T3 Tailwheel Suspension System P/N: ABI-51525 Manufactured by ABI, LLC Doc No.: ABI-51525-II REV A October 31, 2023 ABI‐51525 Cessna 170 & C305A (USAF O‐1A) T3 Tailwheel Suspension System Installation Instructions REV A Page 2 of 9 Table of Contents 1 Introduction 1.1 Purpose 2 Kit Components 3 Applicability 4 Equipment Description 5 Installation Instructions 5.1 Remove Existing Equipment 5.2 Install T3 Tailwheel Suspension System 5.3 Weight and Balance Computation 6 Document Distribution 7 Appendices 7.1 Appendix A – ABI-51525 Assembly Drawing 7.2 Appendix B – Bolt Torque Specifications ABI‐51525 Cessna 170 & C305A (USAF O‐1A) T3 Tailwheel Suspension System Installation Instructions REV A Page 3 of 9 List of Revisions Revision Date Page Description - 6/19/2018 ALL Initial Release A 10/31/2023 4-6 Revised applicable models, added Section 5.1.7 ABI‐51525 Cessna 170 & C305A (USAF O‐1A) T3 Tailwheel Suspension System Installation Instructions REV A Page 4 of 9 1 Introduction This manual addresses the installation instructions for the Textron Aviation, Inc. (Cessna) 170 & Regal Air, Inc. (Cessna) 305A (USAF O-1A) T3 Tailwheel Suspension System, P/N ABI-51525. It is published for the guidance of qualified maintenance personnel responsible for the installation and continued airworthiness of a T3 Tailwheel Suspension System. 1.1 Purpose This manual provides the necessary procedures to accomplish the installation of the ABI, LLC T3 Tailwheel Suspension System, P/N ABI-51525 onto a Cessna 170 series or Cessna 305A aircraft. The manual should be retained by the owner or the maintenance facility for future reference. 2 Kit Components The ABI, LLC T3 Tailwheel Suspension System assembly contains all the components required to replace the existing tail spring on a Cessna 170 or Cessna 305A (USAF O- 1A). The ABI-51525 assembly is shown in Appendix A. 3 Applicability The ABI, LLC T3 Tailwheel Suspension System, P/N ABI-51525 is applicable for installation on a Cessna 170B, Cessna 305A (USAF O-1A), or a Cessna 170/170A with the Textron Aviation, Inc. (Cessna) p/n 0512154-1 Bracket, Tailwheel Mounting installed. 4 Equipment Description The suspension system consists of a coil-over style tail spring assembly as a direct replacement for the leaf spring style tail springs currently used. The design features a coil spring and an oil shock that work in tandem to absorb landing energy and reduce rebound. The result is less stress on the fuselage and improved aircraft control on landing rollout, take off, and taxi. The suspension system incorporates structural mounting brackets and side fixture plates to provide a stable basis upon which the suspension system operates. AN hardware is used to fasten the assembly together and to secure the assembly to the fuselage. There are two adjustable portions of the assembly, one is the pre-load, and the other is the rebound. The pre-load is adjusted by turning the spring perch nut to either compress or extend the spring’s static length. Rebound damping is adjusted by turning the adjustment knob at the top of the shock. Both settings are preset at the optimum setting from the factory and are ABI‐51525 Cessna 170 & C305A (USAF O‐1A) T3 Tailwheel Suspension System Installation Instructions REV A Page 5 of 9 not intended to be adjusted. Pilots should regularly check to verify the factory settings are maintained during routine pre-flight inspections. The OEM tailwheel bracket commonly has a crack in the radius on each side of the bracket (shown below) when used under severe conditions. The T3 suspension system was specifically designed to bypass this area and reacts all tailwheel loads into the heavier tail wheel support structure ahead of the area where cracking occurs. Thus, the T3 suspension system eliminates the need for repetitive inspections of this area. The only action necessary if cracks are found in the area shown during this installation will be to clean and corrosion protect the area. This area will be unloaded and further crack growth will not occur so only environmental protection of the part is required. Figure 1: Crack Location in 0512154-1 Bracket (each side) 5 Installation Instructions 5.1 Remove Existing Equipment 5.1.1 Chock the aircraft’s front tires and lock brakes so the aircraft cannot roll 5.1.2 Properly raise the aircraft tail off the ground following the airframe manufacturer’s instructions. 5.1.3 Unbolt existing tail spring from fuselage. 5.1.4 Disconnect the steering chains and spring from the rudder horn. 5.1.5 Remove existing tail spring assembly from airplane. ABI‐51525 Cessna 170 & C305A (USAF O‐1A) T3 Tailwheel Suspension System Installation Instructions REV A Page 6 of 9 5.1.6 Remove the bolt securing the tailwheel assembly to the spring and inspect for wear. ABI, LLC recommends replacing any hardware that appears to have any non-cosmetic wear or damage. 5.1.7 Visually examine the area shown in Figure 1 carefully for cracks. If cracks are found, clean and treat the area in accordance with AC 43.13-1B, Para 6-50 using epoxy primer such as MIL-PRF-23377 or equivalent. No further action is required. 5.2 Install T3 Tailwheel Suspension System 5.2.1 Install the T3 Tailwheel Suspension System in place of the leaf spring in reverse order. Replace hardware with hardware supplied in the optional installation kit, or new hardware of appropriate size. Refer to the torque specifications shown in Appendix B. 5.2.2 Install the T3 attach block (Item No. 22) into the unclamped opening where the leaf spring resided previously. It should be installed with the beveled edges facing upwards and the horizontal hole protruding out of the tail cone. Line up the front leaf spring clamp bolt holes with the attachment block.