Clinserts are interchangeable with MS part numbers

1. possesses such functional and physical characteristics as to be equivalent in performance, reliability, and maintainability, to another item of similar or identical purposes; and
   (2) is capable of being exchanged for the other item
   (a) without selection for fit or performance, and
   (b) without alteration of the items themselves or of adjoining items, except for adjustments.
   
   Clinserts are a substitute item for MS part numbers

Clinserts possesses such functional and physical characteristics as to be capable of being exchanged for another only under specified conditions or in particular applications and without alteration of the items themselves or of adjoining items.

Clinserts are Form, Fit and Function
1. Form: The shape, size, dimensions, mass, weight, and other physical parameters which uniquely characterize an item.
2. Fit: The ability of an item to physically interface or interconnect with or become an integral part of another item.
3. Function: The action or actions which an item is designed to perform.

Clinserts are two-way interchangeable

classes Common types of Interchangeability and Substitution (I&S) are as follows:
• Two-way interchangeable
• One-way interchangeable
• Substitutional
• Not interchangeable

See also:

https://www.fma.no/maanor/regulations/Regulation%20for%20approved%20military%20aircraft%20parts.pdf/_/attachment/inline/0be44fc9-c00c-4f1b-b86e-6e1b1814889f:377390145044fef14e82a61243b83af37b031dc7/Regulation%20for%20approved%20military%20aircraft%20parts.pdf