1975–1981 Piper Seneca II PA-34-200T Aircraft Service Manual (P/N 761 590)

The Piper service manual, P/N 761 590, covers the 1975–1981 Seneca II PA-34-200T, a six-place twin-engine aircraft with turbocharged engines. This is the October 11, 1979 reissue, with revisions recorded through February 5, 1997.

• Airframe and flight controls: Wing and empennage removal, control-surface balancing, cable rigging, and adjustment of ailerons, stabilator, rudder, and flaps.

• Hydraulics, gear, and brakes: Pump and actuating-cylinder repair, gear alignment, retraction-system testing, Cleveland brake service, and gravity or pressure bleeding.

• Powerplant service: Engine removal and installation, Bendix magneto inspection and timing, propeller-governor adjustment, and turbocharger wastegate setup.

• Fuel systems: Tank and optional fuel-cell repair, selector-valve servicing, auxiliary-pump checks, and fuel-quantity gauge calibration.

• Electrical and instruments: Alternator and starter overhaul, voltage-regulator testing, ELT checks, and system wiring diagrams with serial-specific configurations.

• Cabin and optional equipment: Janitrol heater overhaul, propeller and pneumatic deicer testing, oxygen-system service, air-conditioning maintenance, and synchrophaser checks.

The manual specifies that only qualified personnel should perform its procedures; its rigging, bench-testing, and system-repair sections are intended for aircraft maintenance work.

Airframe Inspection and Control Rigging

Ground-handling instructions cover jacking, weighing, and leveling. Main- and nose-gear lubrication charts accompany the inspection reports, while structural procedures address wing panels, empennage surfaces, windows, and doors.

Control-surface balancing accounts for paint, repairs, and installed equipment. Rigging data combines control travels with cable-tension corrections for ambient temperature, supported by fabricated rigging-tool drawings. Reference tables cover electrical bonding resistance and flare-fitting torques for aluminum and steel tubing.

Landing-Gear Hydraulics and Brake Repair

The Schematic Diagram of Hydraulic System supports pump testing and fault tracing. Troubleshooting charts distinguish hydraulic supply problems, actuator leakage, gear-locking faults, and brake complaints. Oleo service tolerances and master-cylinder repair procedures accompany the wheel and brake instructions.

The manual warns that trapped pressure during manual gear cycling can release the downlocks and allow the gear to collapse when the wing jacks are removed. It also warns against removing the compressed nose-gear centering spring from its shaft assembly; the retaining pins have fused heads.

Powerplant Service and Overhaul Boundaries

Magneto procedures cover internal timing and installation on the counter-rotating engines. The Schematic Diagram of Turbocharger System accompanies Rajay turbocharger and wastegate setup, while propeller service includes Hartzell governor rigging and blade-track checks.

Engine coverage extends to removal, installation, minor repair, and servicing. Major engine repairs, overhauls, and engine torque data require the component manufacturer's literature. Internal propeller repair is referred to Hartzell or a certified repair station.

Fuel Indication and Electrical Fault Tracing

Fuel-system instructions distinguish installations with and without primer systems. Installed sender/gauge checks and the Resistor Set-up/Test for Fuel Quantity Gauge help isolate inaccurate fuel indications before a sender or gauge is replaced.

Separate radio-bus schematics cover serial numbers 34-7570001–34-7570337, 34-7670001–34-8070001, and 34-8070002 and up. Instrument documentation also distinguishes gyro-pressure and pitot-static configurations. Electrical test sections address regulator adjustment, overvoltage protection, and starter bench checks.

Heaters, Deicing, and Accessory Service

Janitrol heater instructions include combustion-tube inspection and bench testing. The pressure-decay test is referred to separate Janitrol literature. The Pneumatic Deicer System Schematic and Air Conditioning Wiring Schematic support accessory diagnosis; propeller-deicer checks cover timers, brushes, and slip rings.

Oxygen coverage includes portable units and the optional fixed system. Sankyo air-conditioning procedures cover compressor removal, installation, oil checks, and drive-belt adjustment; internal compressor service requires a suitably equipped specialist shop.

AutoControl and AltiMatic autopilot servicing requires separate system-specific manuals. Synchrophaser instructions distinguish Auto Synch/Manual and Phase Adjustment controls and specify Hartzell Test Set B-4467 for wiring-harness checks.

Examples of Magneto Timing and Oleo Dimensions

These settings are a small sample of the manual's adjustment data. Bendix 25 Series magneto timing is listed at 20° BTC, with separate firing orders for the left and right engines.

Main-gear oleo piston-tube exposure is 3.60 ± 0.25 inches with the airplane on a level surface under normal static load, defined as empty weight plus full fuel and oil.

Search, Bookmarks, and PDF Contents

Text access and wiring detail: Embedded OCR supports text searches across the service sections. PDF bookmarks link sections, procedures, tables, and figures. Small wiring labels require zooming; some faint or incomplete labels remain difficult to read.

One printable 675-page PDF contains all three Aerofiche cards of this single service manual. The total includes the three original card covers, revision records, indexes, and 22 intentionally blank pages.