Service Letters

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
    Seat Tracking Improvement
    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