Text in force at CS27-10: from CS27-0, effective 14 Nov 2003.
(a) The methods of fabrication used must produce consistently sound structures. If a fabrication process (such as gluing, spot welding, or heat-treating) requires close control to reach this objective, the process must be performed according to an approved process specification.
(b) Each new aircraft fabrication method must be substantiated by a test program.
ED Decision 2003/015/RM · Source