PA28 Pilot Operating handbooks
PA28-181 – Pilot Operating Handbook
PA-28-181 Archer II  – Pilot Operating Handbook
NEW PA-28-161 Warrior II – Pilot Operating Handbook

FAA Safety Leaflets –
American Airspace.
VFR-symbols
Intro to VFR Chart Symbols
Flight Review
Fuel Awareness
Emergency Procedures
Making the right decision
Collision Avoidance
Take off and Landings
Engine Ops
Thunderstorms and ATC
Misfueling
Say It Right card
FAA Tips Crosswind TO and Landings
VFR Takeoff
Runway Markings
Carb Ice
Towered Airfield Proc
Non-Towered Airfield Proc

FAA Publications –
Pilot Handbook of Aeronautical Knowledge
Instrument Flying Handbook
Instrument Procedures Handbook
Airplane Flying Handbook

Free Books –
Aerodynamics for Pilots