14 CFR Subpart C Section 25-305
14 CFR Subpart C Section 25-305
(OP)
Friends, I'd like to know if you have any useful comments or suggestions on how you have interpreted this regulation.
I wrote about it here: http://www.stressebook.com/14-cfr-subpart-c-sectio...
Would be nice to know your thoughts as well.
I wrote about it here: http://www.stressebook.com/14-cfr-subpart-c-sectio...
Would be nice to know your thoughts as well.
Aerospace Stress Analysis and FEA Courses
http://www.stressebook.com
Stressing Stresslessly!





RE: 14 CFR Subpart C Section 25-305
Having been a DER now for over 18 years, the FAA requires us to show compliance to the rule, not interpret it. However, obviously, the working level engineer needs to understand what his substantiation needs to comply with. As a recommendation, try looking into FAA Advisory Circular AC 25-21 "Certification of Transport Airplane Structure". It attempts (weakly albeit) to provide some background and intent of the rule. The other place to look is into the earlier CAR 4b equivalent regulations and predecessors. These where written at a time when we did not have soo much assistance from the legal folks and actually prescribes regulations in laymen terms.
Good luck
RE: 14 CFR Subpart C Section 25-305
I definitely agree the terminology of "interpret" is mainly to understand, but yes it is required to be complied with.
Are you on linkedin by any chance? Would love to connect with you there.
Aerospace Stress Analysis and FEA Courses
http://www.stressebook.com
Stressing Stresslessly!
RE: 14 CFR Subpart C Section 25-305
RE: 14 CFR Subpart C Section 25-305
Aerospace Stress Analysis and FEA Courses
http://www.stressebook.com
Stressing Stresslessly!
RE: 14 CFR Subpart C Section 25-305
Aerospace Stress Analysis and FEA Courses
http://www.stressebook.com
Stressing Stresslessly!
RE: 14 CFR Subpart C Section 25-305
Aerospace Stress Analysis and FEA Courses
http://www.stressebook.com
Stressing Stresslessly!
RE: 14 CFR Subpart C Section 25-305
I will try to address both of your comments. During a review of data to demonstrate compliance, many aspects are looked at. The FAA does provide a lot of guidance however. Particularly, you can find guidance in the FAA Advisory Circulars which present acceptable methods of compliance but of course they are not the only way to show compliance. Additionally, thru DER recurrent training, the FAA provides training material which also provides guidance. In fact, one of the recent training courses provides a very thorough discussion of the use of finite element models and the expected levels of validation for demonstrating compliance. All of this material is available thru the FAA website.
With regards to the older regulations, the couple of links you presented stressbookllc are indeed some of the documents I mentioned. However, the following link a the transportation department (which can be reached thru the faa website) presents full copies of all of the older regulations:
http://specialcollection.dotlibrary.dot.gov/Conten...
In particular, if you look thru the table of contents, locate the CAM 4 manual and it contains numerous appendices with guidance material. Also, if you look thru the older regulations you will find numerous technical approaches to the regulations.
good luck
RE: 14 CFR Subpart C Section 25-305
I think crackman would say that when performing the compliance review to compare the design data to the regulations, if a regulation requires "interpretation" to determine exactly what has to be complied with, then only the FAA can make that call. I expect to be corrected if I am off base.
In the case where tbuelna used the word "interpret" I think I would use the words "compare and evaluate" instead. The idea is that the regulation should give the standard, and the DER either finds compliance with the standard or not. If the standard itself is fuzzy (meaning none of the sources crackman identified such as an AC, seminar, policy letter, white paper, order, etc exist to clarify the standard) then only the FAA can clear up the fuzziness of the standard.
RE: 14 CFR Subpart C Section 25-305