Piper PA-23-235 Apache & PA-23-250 Aztec 1960–1981 Service Manual OEM (P/N 753-564)

• Covers 1960–1981 Piper PA-23-235 Apache and PA-23-250 Aztec variants, including 14-volt, 28-volt, and six-place configurations.
• Official Piper Aircraft publication (P/N 753-564, reissued February 1981), containing all interim updates for the production run, including specialized turbocharger and oxygen systems.
• 1,309 pages featuring 52 exploded-view diagrams, 35 fuel and hydraulic schematics, and 23 comprehensive torque and service-limit tables.
• Features comprehensive overhaul procedures for the hydraulic Powerpak, Janitrol and South Wind combustion heaters, Scintilla magnetos, pneumatic de-icer systems, and AltiMatic autopilots.
• Details step-by-step tear-downs for Delco-Remy alternators, Hartzell propellers, Weldon rotary fuel pumps, Bendix RSA fuel injection systems, and AiResearch turbochargers.

Documented Aircraft Systems

This official reference details the inspection, handling, and structural verification requirements for the PA-23 twin-engine monoplane series. It directly supports daily shop work by providing exact factory baselines for accurate diagnostic procedures. By referencing this digital PDF directly at the aircraft, mechanics can continuously compare intricate wiring diagrams to the actual airframe, accelerating the troubleshooting workflow. Whether you are calibrating fuel systems or repairing cabin environmental controls, the documentation prevents costly trial and error. Power plant servicing data covers both carburetor and fuel injection setups extensively. Additionally, the electrical section maps out generator and alternator configurations across the entire Apache and Aztec airframe life cycle.

Completing heavy maintenance tasks—such as rebuilding the air-oil oleo struts, tearing down the hydraulic Powerpak, or internally timing the magnetos—typically requires outsourcing to expensive specialized facilities, but this manual outlines the exact repair procedures to keep that work in-house. To further clarify complex mechanical relationships, the content incorporates concrete visual aids like the Generator Wiring System Schematic, Flow Diagram Landing Gear Selector Lever Down, Alternator Paralleling System Wiring Schematic, Hydraulic Powerpak Exploded View, and the Nose Gear Oleo Strut Assembly drawing.

Specifications and Reference Data

For precise bench work and line maintenance, the manual supplies essential tolerances and factory specifications. Mechanics rely on these charts for multi-stage bolt torque values and landing gear service limits. This includes specific tire pressures for 4-ply and 6-ply configurations, ranging from 27 to 46 psi. You will also find engine oil sump capacities listed at exactly 12 U.S. quarts. Further reference materials detail cable tension settings, consumable material vendor listings, and oxygen bottle pressures relative to ambient temperature.

When maintaining the PA-23 series, technicians should be aware of a few specific repair pitfalls. During a Powerpak overhaul, even minor mishandling of the poppet seats or check valves will cause irreparable damage to the sealing surfaces, requiring the entire unit to be sent out for a complete factory overhaul. Furthermore, improper routing of the alternator blast tubes can allow the internal wire coil to chafe against the field terminal posts, potentially shorting out the entire charging circuit.

Aviation safety remains paramount. This documentation serves as a vital reference tool for theory and system familiarization. Always verify procedures against the latest FAA-mandated service bulletins and consult certified A&P mechanics before initiating active maintenance on any aircraft.