Unknown Airleak Passes Air Loss Rate Test

Unknown leak passes air loss test rate, is this a violation? I think old school thought was that it was still a violation. This question began because of a dataQ. I too personally feel that a leak is a violation and reaches OOS when it passes the air loss test rate, however with that being said, I will explain the argument, and a valid one, that prompted my question. 393.45 d states: “….which would adversely affect the performance of the brake system.” Now considering the leak at a proper connection or a not identifiable location, the vehicle would not be OOS unless it fails the air loss test rate procedure. The argument thus is that the “adverse affect” has been set at failure to pass the air loss test and therefore a leak that does not rise to that level would not be a violation. Again, I see both points and feel we need to get some consistent guidance. As a courtesy to the dataq I reached out to a couple people nationally and got concurrence with both directions. At this time, it appears we need to get this to committee and set some standards.

I agree with Brian,"John is simply quoting FMCSR 393.45(d)…… it is not an interpretation. When you look at the language of the complete section that is quoted one does not need to have an air leak that “would adversely affect the performance”. A violation exists when you have an air system that is not “free of leaks”. I read the regulation as being three part, each a separate condition. We did discuss this issue when handling Issue Request 11-029-VEH “Audible Air Leak at Other Than a Proper Connection”. Although the issue did not specifically address this issue the discussion would be that a leak at a proper connection would be a violation if an air leak is present but not OOS until it failed the air loss rate test. This was the issue request that added photos to the OOS criteria showing a proper connection and one that is not. (d) Brake tubing and hose connections. All connections for air, vacuum, or hydraulic braking systems shall be installed so as to ensure an attachment free of leaks, constrictions or other conditions which would adversely affect the performance of the brake system." in principle but believe the issue is how it is written and decided to run it by an English expert, here is what they said and therefore where the problem lies. That’s why I believe we need to get either an interpretation on what FMCSA intended or at least provide some guidance through CVSA. I believe any leak, common sense, should be a violation and have always supported that but as you can see one could interpret it otherwise, as has been done. Thanks! Here are two possible interpretations of the statement: 1. … to ensure an attachment free of leaks, free of constrictions, and free of other conditions that would adversely affect the performance 2. … to ensure an attachment free of leaks that would adversely affect the performance, free of constrictions that would adversely affect the performance, and free of other conditions that would adversely affect the performance. It’s interesting to note that, in each case, the correct conjunction is “and” rather than “or”. The use of “or” just adds further confusion to the meaning of the sentence. And, you will note that I have replaced “which” with “that”. Since this is a restrictive clause (regardless of which interpretation you choose), it is more proper to use “that” instead of “which”. You will also note that I have added a comma after the next-to-last item in the list. This is called a serial comma, and it is preferred to use it (but not required unless its omission results in ambiguity). Grammatically, either interpretation could be applied. Lists like this often leave themselves open for fuzzy interpretation. However, based on common sense, it appears that the first interpretation (above) makes a lot more sense.

Provide consistent guidance on whether an air leak that passes the air loss test rate is a violation or does the violation not occur until the air loss fails the air loss test rate.