Posted on October 9, 2026 Kyle Salem
ATA codes help technicians, maintenance planners, and parts researchers locate aircraft information by system. Instead of searching an entire manual for landing gear or electrical power information, readers can begin with the chapter assigned to that subject.
This numbering framework creates a recognizable structure across technical publications. However, a chapter number is only a starting point: it does not identify an exact replacement component or provide instructions for performing maintenance. Understanding how chapters connect to sections, tasks, and parts references makes the system more useful. This guide explains that relationship, introduces common aircraft ATA codes, and demonstrates a practical research workflow.
ATA stands for Air Transport Association. ATA codes classify aircraft systems and technical subjects through a standardized numbering framework.
According to Airlines for America’s description of iSpec 2200: Information Standards for Aviation Maintenance, ATA Spec 100 and Spec 2100 were incorporated into iSpec 2200 in 2000. The standard includes the industry numbering system for aircraft systems and chapters.
The publisher also offers an ATA Standard Numbering System extract specifically covering system and chapter numbering. This is an authoritative reference for the framework, while aircraft-specific publications explain its implementation. A4A Publications
For component research, ASAP Aerospace’s ATA chapter directory provides another browsing route. Its listings supplement aircraft documentation rather than establish installation eligibility.
A commonly encountered ATA reference uses three pairs of digits:
The chapter identifies the broad system or technical topic. The following pairs narrow the reference within that chapter.
This is a common format, not a guarantee that every publication uses identical numbering depth or lower-level organization. Check the numbering explanation in the document being used.
The following breakdown is illustrative:
Read these elements from broad subject to narrower reference. Their precise interpretation depends on the applicable publication.
A reference such as 32-00-00 does not identify a particular inspection, removal procedure, or replacement part. A complete task reference may contain additional identifiers.
A chapter code answers, “Which technical subject is involved?”
A maintenance task identifies a particular operation. Its instructions include prerequisites, warnings, required equipment, procedural steps, and applicable limits.
Only the applicable maintenance data, approved where required, should be used to perform or authorize maintenance. A general article or supplier catalog cannot replace that data.
This selected ATA codes list covers representative chapters rather than every assigned subject. Titles below use familiar chapter wording; check the applicable standard and aircraft publication for exact titles and implementation.
|
ATA Code |
Chapter Subject |
|
ATA 05 |
Time Limits/Maintenance Checks |
|
ATA 12 |
Servicing |
|
ATA 24 |
Electrical Power |
|
ATA 27 |
Flight Controls |
|
ATA 28 |
Fuel |
|
ATA 29 |
Hydraulic Power |
|
ATA 32 |
Landing Gear |
|
ATA 53 |
Fuselage |
|
ATA 57 |
Wings |
|
ATA 72 |
Engine |
|
ATA 79 |
Oil |
|
ATA 80 |
Starting |
ATA 05 and ATA 12 concern broad maintenance and servicing activities. They help readers locate scheduling, check, and servicing information.
These subjects may connect to system-specific instructions elsewhere. A servicing reference should therefore be read with its prerequisites and cross-references.
ATA 24, 27, 28, 29, and 32 separate electrical power, flight controls, fuel, hydraulic power, and landing gear information.
Recognizing these distinctions helps narrow research. However, a fault involving one system can originate in another, so the chapter classification should not be treated as a diagnosis.
ATA 53 and ATA 57 concern fuselage and wing structures. Structural tasks can also reference general practices, material requirements, and inspection instructions.
ATA 72, 79, and 80 distinguish the engine, oil system, and starting system. These related subjects require different initial research paths, even when they concern the same engine installation.
Consider a reader researching a landing gear wheel assembly.
This example demonstrates document navigation only. It is not an aircraft-specific maintenance procedure, and no task or figure number is being invented.
The reader recognizes landing gear as the relevant subject and starts with ATA 32.
Before proceeding, they identify the aircraft model and configuration. This prevents information from another aircraft or modification standard from entering the research.
Using the applicable Aircraft Maintenance Manual index, the reader finds the relevant wheel-related section and selects the required task.
They record the actual task identifier from that manual. They also check effectivity, revision status, prerequisites, and referenced instructions.
The chapter directs them toward the subject; the task supplies the operation-specific requirements.
In the applicable Illustrated Parts Catalog, the reader locates the assembly illustration and corresponding item entry.
They check the figure, item number, part number, description, and effectivity notes. Any alternatives or supersessions require confirmation through the applicable records.
The confirmed identifier can then support supplier research. The ATA 32 landing gear parts catalog offers chapter-based browsing, but catalog placement alone does not prove that a listed component matches the assembly.
The useful output is an exact component requirement supported by aircraft documentation, rather than a chapter number alone.
ATA system codes help connect a reported concern with the appropriate technical subject. They also make maintenance records easier to organize and retrieve.
However, an abnormal indication can involve the monitored equipment, its sensor, wiring, or electrical supply. The first chapter provides context rather than proof of the failed component.
Follow the applicable fault-isolation sequence and cross-references. Replacing an item because its chapter matches the reported system can overlook the underlying cause.
When recording findings, include the actual task reference and results rather than only the chapter classification.
Searches for “FAA ATA codes” often concern the FAA’s Joint Aircraft System/Component, or JASC, classification.
The FAA describes JASC as a modified version of ATA Spec 100 numbering. Its reference table uses four-digit codes and abbreviated titles to support coding and review of aircraft structures and systems data, including service difficulty reports.
ATA chapter references and JASC codes are related, but they should not be treated as interchangeable. Use the framework required by the publication or reporting process.
Neither is a manufacturer part number. A classification organizes information; a part number identifies a component design or configuration within the manufacturer’s identification system.
Chapter-based browsing is useful when the system is known but the component reference still needs investigation.
For example, ASAP Aerospace lists part number 1111A0000-01 under ATA 27 Flight Controls. That record illustrates how a supplier associates an identifier with a chapter.
Before treating any listing as a match, confirm:
Similar descriptions and shared chapter classifications do not establish interchangeability.
They provide common chapter classifications. Applicable chapters, lower-level organization, and technical content can differ between aircraft and publications.
No. Multiple components share a chapter. Use the applicable parts documentation to establish the required identifier and configuration.
Not necessarily. It commonly represents a chapter-section-subject reference. Full task identifiers and their meanings depend on the publication.
Use a chapter code to locate the subject, a task reference to locate the procedure, and a part number to identify the component. Keep those roles distinct.
For broader component navigation, the ATA directory linked above provides a starting point. Carry forward the aircraft-specific references and verified identifiers when comparing listings
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