AS9100 Procedures vs Work Instructions: What Is the Difference?

Author : David Smith | Published On : 27 Aug 2026

For aerospace organizations, effective documentation is essential for maintaining consistent processes, controlling production activities, and demonstrating conformity. Two commonly used types of QMS documentation are AS9100 procedures and work instructions. Although they are related, they serve different purposes within an aerospace quality management system.

Understanding the difference helps organizations create practical AS9100 documentation without making the QMS unnecessarily complicated.

What Are AS9100 Procedures?

AS9100 procedures describe how a process is managed, including its purpose, scope, responsibilities, activities, controls, and required records. They generally provide a process-level view of what needs to happen, who is responsible, and when activities are performed.

For example, an AS9100 supplier control procedure may define how suppliers are evaluated, approved, monitored, and periodically reviewed. It establishes the overall process without necessarily explaining every individual task performed by an employee.

Organizations can use well-structured procedures to support AS9100 QMS implementation, process consistency, internal audits, and control of documented information. Preparing AS9100 QMS procedures can help organizations structure their documentation effectively.

What Are AS9100 Work Instructions?

Work instructions provide more detailed, task-level guidance. They explain how a particular activity should be performed, often using sequential steps, tools, equipment, specifications, acceptance criteria, or other information needed by personnel performing the task.

For example, a manufacturing work instruction might explain the exact steps for assembling a component, operating equipment, performing an inspection, or recording measurement results.

Work instructions are therefore especially useful where an activity requires precise and repeatable execution.

AS9100 Procedures vs Work Instructions

The main difference between AS9100 procedures and work instructions is their level of detail and purpose.

AS9100 procedures describe the overall process. They explain the purpose and scope of an activity, define responsibilities, identify required controls, and describe the sequence or framework for carrying out the process. For example, a supplier control procedure can explain how suppliers are evaluated, approved, monitored, and reviewed.

Work instructions provide more detailed guidance for performing a specific task. They may explain step-by-step methods, equipment requirements, operating parameters, inspection criteria, or other instructions employees need to follow during an activity.

In simple terms, AS9100 procedures explain what needs to be done and who is responsible, while work instructions explain how a specific task should be performed.

Are Procedures and Work Instructions Required by AS9100?

AS9100 Rev D uses the broader term “documented information” rather than prescribing a fixed documentation hierarchy of procedures and work instructions. The organization determines the documented information necessary for effective QMS operation based on factors such as its size, processes, complexity, products, and personnel competence.

This means organizations should not create procedures simply because they believe every process must have a document with that title. Instead, documentation should effectively support process operation and demonstrate that activities are performed as planned.

Why Both Matter in an Aerospace QMS

A strong documentation system connects process-level controls with task-level execution. A procedure can establish the overall quality management process, while work instructions provide the detailed guidance needed at the operational level.

For aerospace manufacturers and suppliers, this approach can help improve consistency, employee understanding, traceability, and AS9100 audit readiness.

Organizations developing or improving their QMS can use structured AS9100 procedures together with supporting work instructions, forms, templates, and other documented information to create a more consistent documentation system.

Conclusion

The difference between AS9100 procedures and work instructions is primarily the level of detail and purpose. Procedures define and control processes, responsibilities, and activities, while work instructions provide detailed guidance for performing specific tasks.

When appropriately structured, both types of documentation can work together to support an effective AS9100 quality management system, consistent operations, and controlled aerospace processes.