Comparison
ATA 100 vs iSpec 2200: What Changed
The Short Answer
One Specification Absorbed the Other
ATA Spec 100 was the airline industry's guide to manufacturers' technical data, first issued in 1956. In 2000 it was incorporated, together with ATA Spec 2100, into ATA iSpec 2200. Spec 100 was left frozen at its 1999 revision. iSpec 2200 carries on, with the current revision at 2025.1.
So the two are not rivals to choose between. One is a closed historical document; the other is the live standard that contains its numbering. When a buyer asks for “ATA 100,” the useful question is what they actually need delivered.
Lineage
From Spec 100 to iSpec 2200
- 1956: Spec 100 is first issued
- ATA Spec 100, Manufacturers' Technical Data, set format and content guidelines for the technical manuals that aircraft manufacturers and suppliers write for airlines, plus the industry-wide systems numbering that became known as the ATA chapters. It was written for conventional printed documentation.
- Before 2000: Spec 2100 covers digital data
- ATA Spec 2100 is listed as Digital Data Standards for Aircraft Support. It addressed technical information prepared as digital media. Sources disagree on when it was first issued.
- 2000: both are incorporated into iSpec 2200
- A4A states that in 2000 Spec 100 and Spec 2100 were incorporated into ATA iSpec 2200, Information Standards for Aviation Maintenance. Its e-Business site words the same event as the two being replaced. Both older specifications stop at their 1999 revision level and are not updated.
- 2000 to 2025: iSpec 2200 keeps being revised
- iSpec 2200 began with revision 2000.1 and is still revised; the current revision is 2025.1, whose notes describe attribute fixes across its DTDs. Spec 100, by contrast, is a frozen document.
What Changed
More Than the Chapter Numbers
- From guidelines for print to a data standard
- Spec 100 described what a printed manual should contain and how to number it. A4A describes iSpec 2200 as a standard for the content, structure, and electronic exchange of aircraft engineering and maintenance information, a suite of data specifications covering maintenance requirements and procedures and aircraft configuration control.
- Machine-checkable structure
- The e-Business program lists SGML Document Type Definitions as part of iSpec 2200. A DTD lets software validate that a manual is built the way the specification says, which a paragraph of guidance cannot. Whether a given revision also ships XML schemas is worth checking in the download package of the revision you license.
- A living revision cycle
- Because iSpec 2200 is revised, a contract that cites it should name a revision. Citing Spec 100 can only mean the 1999 revision, since nothing later exists.
- The numbering moved house, not away
- The ATA Standard Numbering System is part of iSpec 2200, so the chapter numbers survive in the new specification. Our iSpec 2200 standards page lists them; this article does not.
In Practice
Why People Still Say ATA 100
The phrase survives because the numbering is what everyone uses daily: maintenance documents, task cards, and parts systems all speak in chapters. A4A's own Spec 100 page notes the numbering is often called ATA system or chapter numbers. Formal documents use the 2200 name; the FAA, for example, cites ATA Spec 2200 when it points manufacturers to a format for service bulletins.
In a contract, though, precision pays. If a statement of work says “per ATA 100,” confirm whether it means the chapter numbering alone, the 1999 specification, or iSpec 2200 at a named revision. Our comparison of iSpec 2200 and S1000D covers the document-versus-database question, and the ATA Spec 1000BR page covers the business rules layer for S1000D on civil aircraft. For supply chain data exchange, which is a different family, see ATA Spec 2000. For the manuals that carry these numbers, see aircraft manual types.
FAQ
Questions We Hear
Is ATA 100 the same as iSpec 2200?
No, but one grew out of the other. ATA Spec 100, first issued in 1956, was incorporated along with Spec 2100 into iSpec 2200 in 2000. Spec 100 is frozen at its 1999 revision; iSpec 2200 is still revised, currently at 2025.1.
What is ATA Spec 100?
The Air Transport Association's specification for manufacturers' technical data: format and content guidelines for printed technical manuals, plus the aircraft systems numbering that the industry calls ATA chapters. The association is now Airlines for America (A4A).
Do people still say ATA 100 chapters?
Yes. A4A's own Spec 100 page describes the numbering as often called ATA system or chapter numbers, and the habit outlived the document. Today the numbering is part of iSpec 2200 as the ATA Standard Numbering System, so the phrase is common shorthand rather than a citation of a current standard.
Is ATA 100 still used?
The numbering is, constantly. The Spec 100 document itself is no longer updated. If a contract or a library says ATA 100, ask whether it means the chapter numbers or the 1999 specification, and which iSpec 2200 revision actually governs the content.
How does ATA 100 compare with S1000D?
They sit at different levels. Spec 100 told manufacturers how to write printed manuals; S1000D is a database-oriented specification for modular content. The ATA chapter logic carries into S1000D numbering for civil aircraft. Our comparison of iSpec 2200 and S1000D covers the document-versus-database difference.
Get In Touch
Know Which Specification Your Library Follows
We work with iSpec 2200 and S1000D libraries. Tell us which revision your contract cites and we will tell you what it commits you to.