ATA Chapters Used Most Frequently

The ATA Chapter Numbering System is the foundation of modern aircraft maintenance documentation. By assigning every aircraft system a standardized chapter number, it enables engineers, technicians, CAMO personnel, lessors, operators, MROs, and manufacturers to communicate efficiently and locate technical information quickly.

Regardless of whether an engineer is working on an Airbus A320, Boeing 737, ATR 72, or Embraer E-Jet, ATA chapter numbers provide a universal reference system that improves maintenance efficiency, reduces errors, and supports regulatory compliance throughout the aircraft's operational life.

For most Airbus and Boeing maintenance activities, engineers primarily work with:

• ATA 21 – Air Conditioning

• ATA 22 – Auto Flight

• ATA 23 – Communications

• ATA 24 – Electrical Power

• ATA 25 – Equipment & Furnishings

• ATA 26 – Fire Protection

• ATA 27 – Flight Controls

• ATA 28 – Fuel

• ATA 29 – Hydraulic Power

• ATA 30 – Ice & Rain Protection

• ATA 31 – Indicating Systems

• ATA 32 – Landing Gear

• ATA 33 – Lights

• ATA 34 – Navigation

• ATA 35 – Oxygen

• ATA 36 – Pneumatic

• ATA 38 – Water/Waste

• ATA 49 – Auxiliary Power Unit

• ATA 52 – Doors

• ATA 53 – Fuselage

• ATA 54 – Nacelles/Pylons

• ATA 55 – Stabilizers

• ATA 56 – Windows

• ATA 57 – Wings

• ATA 71–80 – Engine Systems