Simone Fevola

with respect to proposed change to FAR 25.307. With the revised wording, there is a removal of FAA preference to allow for relliable conservative analysis to be projected to higher load levels. Mostly all text book theory is based on a conservative linearization of analysis and subsequent comparison to material or joint test data. Additionally, less critical load cases are typically complied with by analysis validated against other load case limit or ultimate load testing, thereby eliminating the need for many ultimate test articles due to the strengthening effects of strain hardening and subseqent lack of material conformity. This "clarification would un-intentinally undo that flexibility. Recommend specifying exactly what would contitute "reliable" analysis rather than leaving up to the applicant or FAA what "reliable" means. Therefore recomend changing the word "reliable" to "dependable and conservative". Additionally, as is further expained for intent, consider adding to the regulation itself "Where justified test load levels may be less than ultimate", as this statement is needed to avoid testing all load cases to ultimate which has been previously accepted. The word reliable, is in itself, meant to be "from a reliable source", such as a textbook that is based on conservative theory found to be historically accurate. (IE Bruhn). Might also add something in the explaination about the absolute need to validate models and when lack of validation might be acceptable. It would be helpful. On a personal note, harmoziation is good, but clearer regulations are better.