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SERVICE LETTERS

Service Letter

Subject (Applicability)
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C-135

Landing Gear Thru-Bolt and U-Bolt Inspection and Maintenance

C-139

Inspection and Repair for Lost Rib Nails (Wood Spar)

406

Wood Spar Inspection (Revision A)

417

Optional Inspection Cover Installation (Wood Spar, Revision C)

418

Electrical System Update (Revision A)

419

Fuel Line / Flap Sector Clearance (7GCBC, 8GCBC)

420

Metal Spar Wing Conversion Guidance (Revision A, Pre 7ECA)

421

Seat Belt Retrofit on Early Model Aircraft

422

Aluminum Gear Retrofit (Rev. A, 7ECA, 7GCAA, 7KCAB, 7GCBC,
8KCAB, 8GCBC)

423

Normal Category Gross Weight Increase (8KCAB)

424

Flap Wing Root Pulley and Cable Inspection (7GCB, 7GCBC, 8GCBC)

425

Inspection of Toe Brake Cotter Pin (7ECA, 7GCAA, 7KCAB, 7GCBC, 8KCAB, 8GCBC)

426

Inspection / Upgrade of Wing Tip Attachment (All Models)

427

Inspection of Nicopress Sleeves (Revision B)

428

Inspection of Repaired Wide Rear Seat

429

Inspection of Stereo Headphone Wiring

430

Conversion of 7ECA, 7GCAA and 7GCBC to Lycoming O-320-B2B

431

Inspection Folding Rear Seat Hinge

432

Inspection Folding Rear Sear Restraint Cable

433

Installation of Front Seat Lap Belts  

434

Door Release Pin and Ring

435

Fuselage Inspection for Loose Items

436

Installation Floorboard Extensions or Revised Floorboards

437

One Time Inspection of Folding Front Seat Bottom

438

Inspection of Fuselage Frame at Main Gear Attachment

439

Airbox Inspection (1974 and Newer)

440

Airbox Inspection (IO-390 and AEIO-390 Engines)

441

Sealed Battery Installation; Global Alternate Method of Compliance

442

Inspection of Aileron Hinge Rib and Support (Rev. A, 8KCAB-Newer)

443

Inspection of Aileron Hinge Rib and Support (8KCAB-Older)

444

Installation of Aileron Hinge Reinforcement

445

Aerobatic Maneuvering and Aileron Application (8KCAB)

446

Elevator Control Cables

448

8KCAB Loading Schedule (W&B Correction)

449

Corrosion Inspection and Preventative Maintenance

450

Exterior Washing

451

Bolt Wear at Exhaust Slip Joints

452

Relocation of Cowl Fastener

453

Shroud to Nosebowl Clearance

454

Improved Cabin Heat

455

Air Box Screw/Bolt Abrasion

457

Lycoming Electronic Ignition System Placard
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