easy question: When creating a list of regulations (and the documents that show compliance with those regulations) that apply to our STC, if one of them has been canceled, would we continue to use that regulation+Amdt basis or the successor regulation?

The install is assumed to be non-significant based on 14 CFR 21.101, so we're using the cert basis on the TCDS.

  • $\begingroup$ Until you discuss your change with DAR or FAA, any assumption is a risk factor. Have you followed 21.101-1B - Establishing the Certification Basis of Changed Aeronautical Products? You need to make a solid case to the FAA that using the 'old' rules is adequate. If you can't, you will need to comply with the current rules. It's typically not a simple yes or no, unless you choose to use the new rules. $\endgroup$
    – Gerry
    Jun 25 '19 at 17:17
  • $\begingroup$ @Gerry thanks, I agree that there is risk until we apply, I'm not asking about determining certification basis via 21.101, I'm specifically interested in understanding if what's on the TCDS can be used if it contains regulations which have been canceled. I agree that we will need to either comply with latest regulations or provide an argument as to why we will not be able to do so if we've been found to be significant by the FAA after we submit the PSCP. $\endgroup$
    – Jeremy
    Jun 25 '19 at 17:53
  • $\begingroup$ I agree this is for the DAR or FAA staff to answer. $\endgroup$ Jun 25 '19 at 18:08
  • $\begingroup$ There are two possible results. You will either need to comply with the current rules or you can use the certification basis that defines the aircraft's current configuration. That basis is defined in the TCDS and any applicable existing STCs. Those STCs may be the same as the TCDS or they could be to rules newer than the TCDS but not necessarily current. If you're using the original cert basis and it includes rules that have been rescinded/superseded, that's acceptable. That's kind of the point of the whole discussion. $\endgroup$
    – Gerry
    Jun 25 '19 at 21:15
  • $\begingroup$ Since you mention the PSCP, I'll point out that that is the vehicle for negotiating the plan with the FAA. It's not a case of "Here's my plan." Every one I've dealt with was multiple drafts back and forth until we had a plan that was approved. The cert basis was a big part of that negotiation. $\endgroup$
    – Gerry
    Jun 25 '19 at 21:22

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