Engineering change notice
An engineering change notice (ECN), or change notice, is a document which records or authorizes a change to a specific design. The reasons for the change should also be recorded.
Following sound engineering principles, control and documentation are necessary to ensure that changes are built upon a known foundation and approved by relevant authorities.
"[A] document approved by the design activity that describes and authorizes the implementation of an engineering change to the product and its approved configuration documentation".
An ECN must contain at least this information:
- Identification of what needs to be changed. This should include the part number and name of the component and reference to the drawings that show the component in detail or assembly.
- Reason(s) for the change.
- Description of the change. This includes a drawing of the component before and after the change. Generally, these drawings are only of the detail affected by the change.
- List of documents and departments affected by the change. The most important part of making a change is to see that all pertinent groups are notified and all documents updated.
- Approval of the change. As with the detail and assembly drawings, the changes must be approved by management.
- Instruction about when to introduce the change—immediately (scrapping current inventory), during the next production run, or at some other milestone.
The telecommunications industry has a formal process that takes elements of the ECN and other considerations and combines them into the “product change notice" (PCN). After telecommunications products have been generally available and/or in service for a period of time, it often becomes necessary for suppliers to introduce changes to those products. As a result of implementing these changes - regardless of who performs the actual work - the telecommunications carriers are significantly impacted with respect to labor and resources, etc. Thus, it is imperative that changes to these products are accurately reported and tracked through completion, according to the needs and requirements of the carriers.
The term “product change” includes changes to hardware, software, and firmware that occur over the entire life of a product. Product changes include those considered reportable and non-reportable. These changes may be applied by a supplier, a customer, or a contractor retained by the customer, depending on negotiated agreements. Fundamentally, the customer’s goal is to ensure there is a process by which there is accurate and efficient tracking and reporting of changes to products.
Changes are considered reportable when they affect the performance or life span of a product. Such changes include any that affect the form, fit, function, or the product technical specification (i.e., documentation) of the product. The desire for supplier or customer traceability may result in a reportable change.
The entire PCN process is documented in GR-209, Issue 6, Generic Requirements for Product Change Notices (PCNs).
- Buckley, Fletcher J. (1996) Implementing Configuration Management: Hardware, Software and Firmware. 2nd Edition. IEEE.
- Ullman, David G. (2009) The Mechanical Design Process, Mc Graw Hill, 4th edition.
- A free Word template with fields for this information is available associated with Ullman.