What is inspection control?

When we think about inspection control systems, we are considering activities that provide product assurance, that the personnel performing those activities have the correct training and credentials to do so, and that the product is compliant for the particular attribute examined. Information directly applied or added to the product (without affecting capabilities) or by recorded information (including digital media), are ways to certify the fulfillment or not of inspection procedures. The most common means to indicated product inspection/acceptance are:


  • Stamps
  • Signatures
  • Labels
  • Electronic media

Inspection Control Basics

Figure 1: Sample media types for inspection records.


Historically, NASA’s most common means used to signify an inspection has occurred is a stamp. For consistency, we are going to use the same definition of “stamp” as declared on the STEP SMA-QE-WBT-252 [1], in which a Stamp is: “Any means of physically marking a product or it’s associated documentation with an inspector’s unique mark. Sometimes a signature on a separate form can be used for the same purpose”. In this module, we’ll use the term stamp to indicate any and all of these methods.


In the case of NASA, the accomplishment of product assurance actions shall be attested to by signature, with legible printed name and date or by an inspection control system as electronic medium or stamps. It is also a requirement to use plain English. It is a good policy to use quality stamps to keep a clear record that work products have been inspected by qualified personnel, and when the inspection took place.

The standards MIL-Q-9858, “Quality Program Requirements”, and MIL-I-45208, “Inspection System Requirements”, are the basis upon which inspection control procedures have been developed and are the origins of ISO 9001 and all other quality management system standards and regulations over the world.

The use of “stamp” or unique identifier as a requirement to communicate that an inspection has occurred and to communicate its outcome is not new. To illustrate this in the aerospace industry, let’s look at a direct quote from the Department of Defense Inspection System Requirements [2]:


“Indication of Inspection Status. The contractor shall maintain a positive system for identifying the inspection status of products. Identification may be accomplished by means of stamps, tags, routing cards, move tickets, tote box cards, or other normal control devices.”



Requirements today come directly from NASA and other governing bodies for most agency related projects. To get used to this type of requisites, it is good to review a few samples. SAE AS9100/ISO 9001:


“The organization shall identify the product status with respect to monitoring and measurement requirements throughout product realization.”

NASA common inspection stamp

Figure 2: NASA Sample inspection stamp, courtesy of NASA STEP [1].


It is good to review the Federal Acquisition Regulation Part 46 Standard Inspection Clause which states:


“The Contractor shall provide and maintain an inspection system acceptable to the Government covering supplies under this contract and shall tender to the Government for acceptance only supplies that have been inspected in accordance with the inspection system and have been found by the Contractor to be in conformity with contract requirements. As part of the system, the Contractor shall prepare records evidencing all inspections made under the system and the outcome.”


What NASA policy say about inspection control processes?


“Accomplishment of product assurance actions shall be attested to by signature, legible printed name, and date or by an inspection control system such as inspection stamps or electronic media”.


Inspection control is normally the responsibility of Quality Assurance plan, this means that an inspection control system be implemented and documented wherever quality status stamping is used. QA maintains a traceable control stamp system with supporting procedures to regulate all inspection stamps used by employees.


As mentioned on the STEP SMA-QE-WBT-252 [1]: "Generally quality stamps or electronic mediums are used to indicate the quality status or conditions of material, parts, tools, equipment, assemblies, systems, and/or supporting documentation that have been inspected, certified, calibrated, and/or reviewed". In an aerospace project both the developer and the supporting contractors have important roles to play in inspection control, although different responsibilities. In both cases, the warranty in how they accomplish these responsibilities is the same and is critically important: "There is a guarantee that the responsible inspector or operator personally saw or performed the task literally as stated in the build paper, also referred to as the Build Record, Traveler, or Assembly and Inspection Data Sheet."


In any aerospace related project as in many other disciplines, inspection control is a critical area that must be inherit part of all procedures during development, this is not only important for the internal development, but also because most aerospace projects are going to interact with agencies and entities that require this type of certifications and inspection requirement fulfillment.


Answer "Yes" or "No" if you think that the following actors have a role in Inspection Control:


*Images courtesy of NASA STEP SMA-QE-WBT-252 [1].


Finally, we would like to invite you to watch the following short video about Inspection Control from the "Gemba Academy" Youtube channel [3]: