Aerospace Decimal Classification (ADC)

A Classification for Aeronautics, Astronautics, and Aerospace Sciences

Classification

Aerospace Decimal Classification

Classification Code

ADC

Classification Number

Decimal number identifying a class; e.g. 341

Notation

ADC followed by the decimal Classification Number; e.g. ADC341

Class Term

Term designating a class; e.g. Aircraft Performance

Class

Represented by its Notation followed by the Class Term; e.g. ADC341 – Aircraft Performance

Version

1.0

Version date

2026-09-21

Language

English

Author

Dieter Scholz

Maintained by

Aircraft Design and Systems Group (AERO), Hamburg University of Applied Sciences (HAW Hamburg)

Number of Classes

136

Persistent URL

https://purl.org/aero/classification

License

Creative Commons Attribution 4.0 International (CC BY 4.0)

Contents

• Definition
• ADC Notation, Numbering, and Class Terms
• Rules for Application
• Classification
• Alphabetical Subject Index
• Relationship between 'ADC124 Systems' and 'ATA Chapters'
• Background and Documentation
• Scope Notes
• Citation
• Version History

Available Formats

PDF Excel

Definition

The Aerospace Decimal Classification (ADC) is a hierarchical subject classification for aeronautics, astronautics, and aerospace sciences. It was developed at Hamburg University of Applied Sciences (HAW Hamburg) for the systematic organization, indexing, and retrieval of aerospace-related knowledge and documents. The classification uses decimal notation and is intended, among other applications, for subject indexing in library catalogs and repositories. ADC Version 1.0 comprises 136 classes.

ADC Notation, Numbering, and Class Terms

An ADC notation consists of the Classification Code ADC followed by the decimal Classification Number. The Classification Code identifies the classification independently of the bibliographic data format or database in which the Notation occurs. Example: ADC341. Earlier publications may show the Classification Number without the Classification Code ADC (for example, 341 ). From Version 1.0, the complete Notation includes the Classification Code (for example, ADC341 ).

Numbering of classes on the same level start with '1'. Every new level starts with a '1'. The third digit is followed by a dot, which serves the purpose of visual structuring. A Notation never ends with a dot. A Classification Number contains at least three digits; shorter numbers are filled with zeros e.g. 3 >>> 300.

Class Terms use Chicago-style title case. Class Terms denoting countable classes of physical objects normally use the plural where linguistically appropriate. Class Terms are intended to remain meaningful when used independently. Within the aeronautics branch, established aviation terms do not normally require the qualifier aircraft. Where a Class Term could otherwise refer equally to aeronautics or astronautics, an appropriate qualifier such as aircraft or spacecraft is added.

Rules for Application

ADC should be assigned at the most specific applicable class. Normally, one ADC notation should be sufficient to describe the principal aerospace subject of a document. A second ADC notation may be assigned if the document substantially covers a second subject that cannot adequately be represented by the first notation. Broader classes should not additionally be assigned when their subject content is already represented by a more specific subordinate class. ADC may be used independently of other subject indexing systems.

Classification

Alphabetical Subject Index

The Alphabetical Subject Index lists all Class Terms alphabetically and links each Class Term to its ADC notation.

Relationship between 'ADC124 Systems' and 'ATA Chapters'

The detailed ATA chapter structure is grouped into the broader aircraft-system classes used by ADC. The grouping is designed to cover the applicable ATA chapters without reproducing the full ATA classification. An ATA chapter may be associated with more than one ADC group where its subject matter spans different system categories; ATA 33 is intentionally divided between two ADC groups. ATA references are additional mapping information and are not part of the ADC notation or Class Term.

ADC Class and ATA Chapter

ATA Chapter Numbers and Names

Source:
   SCHOLZ, Dieter, 2005. Aircraft Systems. Lecture Notes, p. 3.
   WIKIPEDIA, 2026. ATA-Kapitel.

Note: The name for ATA 44 Cabin Systems can be confusing compared with ADC124.16 – Cabin Systems. ATA 44 comprises only the electronic cabin systems (avionics): Cabin Core System (44-10), Inflight Entertainment System (44-20), External Communication System (44-30), Cabin Mass Memory System (44-40), the Cabin Monitoring System (44-50), and Miscellaneous Cabin Systems (44-60). In contrast, ADC124.16 – Cabin Systems comprises the predominantly mechanical cabin systems (21, 25, 33, 35, 38, 50).

Background and Documentation

The classification was originally developed by Dieter Scholz in 2013 (as Editor in Chief) for the Aims & Scope (and for manuscript handling) at the journal Advances in Aerospace Science and Technology (AAST). In 2022, the classification was reviewed against DIN 32705 in a Bachelor thesis by Schaugar Taher Gulani at Hamburg University of Applied Sciences; minor revisions were introduced during this thesis work. In 2026 the name Aerospace Decimal Classification (ADC) was established, the Classification Code ADC was added; the terminology consolidated; Class Terms were prepared for independent use in bibliographic indexing; documentation and ATA mapping separated from Class Terms.

• Conference poster (2023)
• Thesis landing page (2022)
• AAST Aims & Scope (2013)

Scope Notes

ADC111.12 Lighter-than-Air Vehicles. Rigid airships are commonly known as Zeppelins. Non-rigid airships are commonly known as blimps.

ADC124 Systems. Systems are considered airframe systems in contrast to engine systems, which are part of ADC123. See above for the Relationship between 'ADC124 Systems' and 'ATA Chapters'.

ADC124.1 Utility Systems. Utility Systems are also called Aircraft Basic Systems. These are predominantly mechanical systems.

ADC124.22 Mission Avionics. Mission Avionics comprises avionics primarily supporting the mission or operational purpose of the aircraft, including civil, special-mission, and military applications. For commercial transport aircraft, this includes cabin electronics supporting the passenger transport mission; for military aircraft, it includes avionics supporting operational mission functions.

ADC125 Weapons. This class comprises weapons themselves and systems and equipment directly concerned with carrying, controlling, aiming, releasing or firing weapons.

ADC224.1 Astrionics. Astrionics denotes electronics and electronic systems specifically for spacecraft. Although avionics is widely used for spacecraft electronics, ADC uses astrionics to distinguish this field from aircraft avionics.

ADC224.3 Photovoltaics. Photovoltaics is fundamental to spacecraft power supply, whereas its use in aircraft is limited to relatively few applications. Therefore, Photovoltaics is classified under Spacecraft Systems and not under Aircraft Utility Systems.

ADC244 Aerospace Philosophy. Aerospace philosophy is primarily concerned with spaceflight but may also address philosophical questions originating from aviation.

ADC300 Aerospace Sciences. Aerospace Sciences comprise scientific and engineering disciplines with applications to both air and space.

Citation

SCHOLZ, Dieter, 2026. Aerospace Decimal Classification (ADC) . Version 1.0. Hamburg: Hamburg University of Applied Sciences. Available from: https://purl.org/aero/classification .

Version History

  Prof. Dr. Scholz
  Aircraft Design and Systems Group (AERO)
  Aeronautical Engineering
  Faculty of Aviation and Automotive Systems
  Hamburg University of Applied Sciences