Service Letters and Service Bulletins were produced by Aircraft Manufacturers to inform all concerned of new maintenance information, modifications, improvments and policies pertaining to the operation and support of their aircraft. Service Bulletins describe mandatory procedures that must be observed for safety reasons. Service Bulletins are identified by the word BULLETIN printed (originally in Red) on the right margin. Service Letters were issued to explain service policies and describe modifications, processes, new products and other information pertinent to the operation, maintenance and repair of our aircraft. Service Letters can be identified by the word LETTER printed (orignially in Blue) on the right margin.
| Letter | Subject | Status | Applicability |
| 68-1 | Availability of Service Letters and ServiceBulletins | Current | AA1, AA1A |
| 68-2, 69-1 | Obsolete | AA1 | |
| 69-1A | Control System Improvements | Supercedes SL68-2,69-1 | AA1 |
| 69-2 | Exhaust System Modifications | Current | AA1 |
| 69-3 | Throttle Control | Obsolete – See Service Manual | AA1 |
| 69-4 | Throttle Control Inspection and Rigging | Inactive – See Service Manual | AA1 |
| 69-5 | Spring Plunger Elimination | Obsolete – See SL-75-1 | AA1 |
| 69-6 | Exhaust System Inspection | Obsolete See SB-116 | AA1 |
| 70-1 | Canopy Screw Inspection | Current | AA1 |
| 70-2 | Nose Wheel Spacer Replacement | Current | AA1 |
| 70-3 | Wheel Fairing Installation | Supercedes SB101,104A | AA1 |
| 70-4 | Canopy Improvements | Supercedes SB102 | AA1, AA1A |
| 70-5 | Landing Gear Inspection | Current | AA1, AA1A |
| 70-6 | Wing Tip Stiffener Inspection | Current | AA1 |
| 70-7 | Vendor Service Publications | Current | AA1, AA1A |
| 70-8 | Rudder Bellcrank Modifications | Current | AA1 |
| 71-1 | Model AA1A Service Manual Supplement | Current | AA1, AA1A |
| 71-2 | Service Information Summary | Current | AA1, AA1A |
| 71-3 | Muffler Inspection | Supercedes SB122 | AA1 |
| 71-4 |
Canopy Track Improvement Windshield/Canopy Hardware Improvement Exhaust Joint Sealing Nose Gear Inpection and Precautions Nose Gear Strut Sealing Static System Improvements Air Vent Improvements Fuel Selector Valve Lubrication Lycoming Service Instructions 1070C and 1237 |
Current | AA1, AA1A |
| 71-5 | Cabin Floor Inspection and Modification | Current | AA1, AA1A |
| 71-6 | AA1A Trainer Owners Manual Correction | Current | AA1A |
| 71-7 | Rudder/Elevator Rib Rivnut Inspection | Current | AA1, AA1A |
| 71-8 | Defroster Outlet Design Improvement | Current | AA1, AA1A |
| 71-9 | Battery Box Cover Modification | Current | AA1, AA1A |
| 71-10 | Carburetor heat/mixture control fitting replacement | Obsolete See SL-74-4 | AA1, AA1A |
| 71-11A | Bungee Inspection | Replaced SL 71-11 | AA1, AA1A |
| 71-12 | Carburetor Air Valve Screw Inspection | Current | AA1, AA1A |
| 71-13 |
Stall Warning Wire Relocation Master Cylinder Operation Windshield/Canopy Improvement Nose Gear Fork Installation Canopy Attachement Improvement Presolite Service Bulletin ASM-5 |
Current | AA1, AA1A |
| 72-1 | Propeller Care and Operation Limits | Current | AA1, AA1A |
| 72-2 | Rudder Rigging | Current | AA1, AA1A |
| 72-3 |
Step Drail Hole Modification Flap Position Indicator Modification Aileron Balance Weight Arm Modification Canopy Latch and Lock Sealing Improvement Canoy Track Teflon Runner Roll Pins Reas Seat Clou Out Covers Tail Tie Down Rings |
Current | AA1, AA1A |
| 72-6 | Fuel Quality and Fuel Quick Drain Placards | Current | AA1, AA1A, AA1B, AA5 |
| 72-8A | Canopy trim Retrofit | Current | AA5 |
| 74-2 | Bondline Inspection Procedures | Current | All Aircraft |
| 74-3 |
Flap Switch Boot Installation Nose Strut Length Increase Control Suface Toque Tube Repair Avo Lyoming Service Publications |
Current | AA1, AA1A, AA1B, AA5 |
| 74-4 |
Windshiled Canopy Attach Screw Torque Canopy Latch Improvement Carburetor Heat/Mixture Control Fitting Improvement Fuel Tank Vent Inpection and Modification Inspection Cover Installation Avco Lyoming Service Instruction No. 1266 |
Current | AA1, AA1A, AA1B |
| 74-5 |
Canopy Lock Sealing Fuel Tank Access Cover Improvement Carburetor Airbox Bearing Replacement Wire Bundle Protection |
Current | AA5 |
| 74-6 | Buss Bar/Bearing Collar Clearance | Current | AA1B, AA5 |
| 74-7 | Park Brake Rigging | Current | AA1, AA1A, AA1B, AA5 |
| 75-1 | Improved Anti Shimmy Washer | Current | AA1, AA1A, AA1B,AA5, AA5B |
| 75-2 | Approved Battery Box & Cover Replacement and Inspection | Current | AA1, AA1A, AA1B, AA5, AA5B |
| 75-3 | Improved Front Seat Bottom | Current | AA5, AA5B |
| 75-4 | Landing Light Replacement | Current | AA1, AA1A, AA1B, AA5 |
| 75-5 | Vendor Service Publications | Current | AA1, AA1A, AA1B, AA5 |
| 75-6 | Spinner Bulkhead Preload | Current | AA5B |
| 75-7 | Improved Fuel Level Visibility | Current | AA1A, AA1B |
| 75-8 | Flap Bondline Inspection | Current | AA5, AA5A, AA5B |
| 75-9 | Spark Plug Lead Fouling | Current | All |
| 75-10 | Parking Brake Improvement | Current | AA1, AA1A, AA1B, AA5A, AA5B |
| 75-11 | Exhaust Stack / Cowl Clearance | Current | AA5B |
| 76-1 | Telex Microphone Replacement | Current | AA1B, AA5, AA5A, AA5B |
| 76-2 | Vendor Service Publications | Current | AA1, AA1A, AA1B, AA5A, AA5B |
| 77-1 | Engine Primer O Ring Replacement | Current | AA1, AA1A, AA1B, AA5A, AA5B |
| 77-2 | Magneto Lead Isolation & Routing | Current | All Models |
| 77-3 | Canopy Lock Release Lever Placard | Current | AA5, AA5A, AA5B |
| 77-4 | Replacement of Induction Air Filter Assembly | Current | AA5B |
| 78-1 | Improved Sun Visor Material | Current | AA5A, AA5B |
| 78-2A | AA5 Series Fuel Sump Tank Repair | Superseded 78-2 | All AA5 Series |
| 78-3 | New Service and Accessory Kits | Current | AA1, AA1A, AA1B, AA5A, AA5B |
| 78-4 | Narco Avionics Service Bulletin ELT-10 No. 10 | Current | AA1C, AA5A, AA5B w/Narco ELT-10 |
| 78-5 | Upholstery Replacement/Herculon Material | Current | AA1B, AA5, AA5A, AA5B |
| 79-2 | Carburetor Mixture Control Retainer | Current | AA5B |
| 79-3 | Carburetor – Improved Sealing to Reduce Throttle Friction | Current | AA5B |
| 79-4 | TCP Fuel Additive | Current | All Aircraft |
| 80-1 | Service Kit SK-150, Autopilot Reactivation | Current | AA5, AA5A, AA5B |
| 81-1 | Replacement of Induction Air Filter | Current | AA1, AA5, AA5A, AA5B |
| L192B | Spark Plug Fouling | Current | All Aircraft |
| 93-1 | Outboard Bearing Bracket Assembly | Current | AA5, AA5A, AA5B |
| 93-3 | Placards | Current | AA5B, AG5B |
| 2002-1 | Fuel Gauge Wire Routing | Current | AG5B |
| 2003-3 | Outboard Wing Spar Attach Bolts | Current | AG5B |