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14 CFR 25.1302 regulation: How much can I modify my design before my Cert Basis is updated to include 14 CFR 25.1302?


3rd post in the series

Whether you are designing and then later modifying a single avionics component or a full aircraft, aviation projects can take a long time to move from paper to production. Since a certification basis is typically defined early in a product’s life, there can be a fairly long lag between the time a new rule is released and when that rule officially gets added to the laundry list of rules that a particular product must comply with.

So, the big question is: when will the newly released 14 CFR 25.1302 get added to your cert basis?

We heard this question a lot during the recent research project that we did for the FAA to gather information about the state of industry and FAA understanding and practices that may impact the effective implementation and compliance with the (at the time proposed) 14 CFR 25.1302 regulation. (Note: This project was conducted before 14 CFR 25.1302 was released on May 3, 2013.)

Changed Product Rule 14 CFR 21.101 has the answers

Some people we talked to wanted to know how much design change would require the Certification Basis to be updated to include the new 14 CFR 25.1302 regulation. And the answer is described in the 14 CFR 21.101 regulation (fondly called “the changed product rule”). The 14 CFR 21.101 regulation is used to establish the Certification Basis of a certification project that addresses a design modification. The regulation 14 CFR 21.101 and its companion advisory circular AC 21.101-1A provide criteria and guidance to determine whether or not a specific change should be considered significant for establishing the certification basis for a changed product and for identifying whether it will be necessary to apply for a new type certificate. And, this is not unique to 14 CFR 25.1302. It is a question that is on the top of avionics and aircraft designer’s minds whenever any new regulation is released.

Some confusion?

But, an interesting point is that for some folks there appeared to be some confusion around this when thinking about 14 CFR 25.1302. The confusion may have stemmed from considering the overarching question: “Will system X be evaluated for compliance against 25.1302?”

And, really to answer this question, we need to consider two distinct steps:

     1.    Will your Cert Basis be updated?
If the product change is significant enough, as determined by 14 CFR 21.101, then the Cert Basis will be updated. If 14 CFR 25.1302 is deemed applicable to the product, then it will likely be added to the Cert Basis along with any other applicable regulations.
    
     2. What systems will be reviewed with additional scrutiny against 14 CFR 25.1302?
If our cert basis was updated to include 14 CFR 25.1302 because the change to the product was significant enough and 14 CFR 25.1302 was considered applicable to the product, then a process will be used to make a determination about which systems will be reviewed with additional scrutiny against 14 CFR 25.1302.
    

It is important and useful to distinguish between these two steps to have a good understanding of how to know whether or not a particular system will be evaluated for compliance against 14 CFR 25.1302 and how detailed that evaluation will be. The last point addressing the level of scrutiny to be applied for 14 CFR 25.1302 depends primarily on the levels of novelty, complexity, and integration of your product. Guidance for determining the level of novelty, complexity, and integration is covered in the advisory circular for 14 CFR 25.1302 (i.e., AC 25.1302-1) but, I’ll save that topic for my next post in this series. So, stay tuned!

Want to learn more? You’ve got options: (1) Read my previous posts in this series, (2) Check back for my next installment in this series, and (3) Read our report Human Factors Research Supporting the Anticipated Release of 14 CFR 25.1302 that describes the research we conducted for the FAA.

 

Handy links to the Changed Product Rule regulation and guidance:

  FAA Regulation 14 CFR 21.101, Designation of Applicable Regulations
  http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgPolicy.nsf
/0/ebc74c0510ebcae686257483004f2295/$FILE/PS-AIR-110-14%20CFR%2021.101.pdf
  This FAA Regulation provides criteria to be used to determine whether or not a specific change should be considered significant.
  
  FAA Advisory Circular AC 21.101-1A, Establishing the Certification Basis of Changed Aeronautical Products
  http://www.faa.gov/documentLibrary/media/Advisory_Circular/AC%2021.101-1A.pdf
  This FAA Advisory Circular (AC) to provides guidance for establishing the certification basis for changed aeronautical products in accordance with Title 14 of the Code of Federal Regulations (14 CFR) § 21.101 and to help identify if it will be necessary to apply for a new type certificate (TC) under 14 CFR § 21.19. It describes the process for establishing the certification basis for amended TCs, supplemental type certificates (STC) and amended STCs, detailing evaluations, classifications, and decisions made throughout the process.

 

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