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

Piper’s service manual for the 1960–1981 PA-23-235 Apache and PA-23-250 Aztec includes six-place configurations and carries P/N 753-564. This copy includes the February 1981 reissue, April 1983 revisions, and the 1986 interim revisions listed for Aerofiche Card 1.

PDF Search, Bookmarks and Wiring Detail

Search and diagram access: An embedded OCR text layer supports searches through the body text, although some schematic lettering is not indexed. PDF bookmarks link to chapters and individual procedures. Small wire codes and terminal labels on dense wiring pages require zooming.

Supplied as one printable, 1,309-page PDF, combining all five Aerofiche cards. The total includes five card cover pages and 48 pages marked intentionally blank.

Airframe Rigging, Powerpak Overhaul and Aircraft Systems

These selected coverage highlights show part of the manual’s contents. Further topics include thermoplastic repairs and emergency locator transmitter battery replacement.

• Structures and flight controls: Structural component removal, control-surface balancing, cable rigging, trim adjustment, and stabilator trim/flap interconnect procedures.

• Hydraulic system: Powerpak disassembly, inspection, reassembly, bench checks, relief-valve adjustment, and internal-leakage tests for valves and actuating cylinders.

• Landing gear and brakes: Oleo strut rebuilding, gear alignment, door and limit-switch adjustment, brake component repair, and pressure-bleeding procedures.

• Power plant service: Engine removal and installation, Hartzell propeller servicing, Scintilla magneto timing, and carburetor and fuel-injector adjustments.

• Fuel system: Fuel-cell replacement and testing, selector and crossfeed valve checks, quantity-indicating tests, and Weldon rotary pump disassembly and reassembly.

• Electrical diagnosis: Generator and alternator checks, component testing and overhaul, starter-motor bench tests, regulator adjustments, and installation-specific wiring schematics.

• Heating and ice protection: South Wind and Janitrol heater overhaul, electrical propeller deicer checks, pneumatic deicer troubleshooting, and oxygen-system service procedures.

This manual is suited to qualified aircraft maintenance personnel with the special tools and test equipment required for the documented work.

Inspection, Structures and Control Rigging

The inspection report is supported by special inspections for items such as flap outboard hinges and fuel-selector control cables. Structural information includes fuselage tubing dimensions, skin materials and thicknesses, and control-surface balance checks after repair or repainting.

Flight-control instructions distinguish aileron, stabilator, rudder, trim, and flap adjustments. Cable-tension and control-travel tables accompany the rigging procedures, with separate treatment of the stabilator trim/flap interconnect on applicable six-place aircraft.

Powerpak Testing and Landing Gear Repair

The hydraulic checking diagrams help distinguish Powerpak leakage from faults in actuating cylinders, shuttle valves, and other system components before parts are selected for repair. The manual identifies hydraulic test equipment, including Piper test unit 753-080, and provides dimensions for fabricated Powerpak tooling.

Step-by-step Powerpak overhaul instructions are supported by the Hydraulic Powerpak, Exploded View and the Flow Diagram, Landing Gear Selector Lever Down. Piper recommends exchange or specialist overhaul where practicable; damage to poppet or valve seats can require return of the unit for overhaul or exchange.

The independent brake circuit is treated separately from the gear/flap hydraulics. Gear and brake reference material includes wheel and brake wear limits, oleo service tolerances, and the Nose Gear Oleo Strut Assembly drawing.

Engine, Propeller and Fuel-System Scope

Power plant coverage centers on removal, installation, servicing, adjustments, and minor repair. Detailed engine and component work is referred to the respective manufacturers’ manuals.

Hartzell coverage includes blade inspection, blade-track checks, and governor rigging; severe damage and internal propeller repairs are referred to Hartzell or an appropriate repair station. Scintilla magneto instructions include internal timing and timing to the engine, with further repairs referred to the manufacturer’s service instructions.

Carburetor and Bendix RSA-5AD1 sections address maintenance, removal, installation, and idle adjustments. Separate AiResearch and Lycoming turbocharger sections distinguish the installations; Lycoming turbocharger adjustment is referred to an authorized overhaul facility.

Weldon pump procedures include shaft-seal installation, reassembly, and bench pressure adjustment. The drive motor is treated as nonrepairable, and detailed pump inspection limits are referred to Weldon’s separate service information.

Charging, Starting and Instrument Systems

Mechanics can compare the Generator Wiring System Schematic and Alternator Paralleling System Schematic with the aircraft’s installation when tracing faults. Delco-Remy and Prestolite sections provide rotor, stator, rectifier, regulator, and starter test information.

The alternator service notes explain how blast-tube chafing can expose its wire reinforcement and short the field terminals. This is a specific installation hazard, rather than a general electrical warning.

Instrument coverage includes gyro-vacuum system checks, removal and installation, and minor adjustments. AltiMatic and other automatic flight-control systems require the separate service literature for the installed equipment.

Heaters, Oxygen and Deicing Equipment

South Wind 940-series instructions cover disassembly, repair, reassembly, fuel-valve tests, and heater burn testing. Janitrol sections include overhaul and operational testing; the specified combustion-chamber pressure-decay test refers to a separate Janitrol maintenance and overhaul manual.

Oxygen servicing includes leak checks and a cylinder-pressure versus ambient-temperature chart. Deicing coverage distinguishes electrical propeller equipment from pneumatic wing and tail boots, including timer-controlled and pressure-controlled installations. Engine synchrophaser checks are also included.

Selected Powerpak Relief-Valve Specifications

Table VI-II lists main relief-valve cracking pressure at 1,250 ± 50 psi for Powerpak models 750P-1 and 31800-0. For models 31800-2, 31800-2M, and 31800-3, it specifies 1,350 psi with a +50/−0 psi tolerance.

Thermal relief-valve cracking pressure is listed at 2,000 ± 50 psi for both groups, alongside the corresponding bench-check and adjustment procedures.