Is FAA AC23-27 usable/valid in Canada?

[digits_]

FAA AC23-27 (source: https://www.faa.gov/documentLibrary/med ... _23-27.pdf) allows US aircraft owners/mechanics to replace hard or impossible to find parts with other alternatives for smaller GA aircraft.

Does Canada have some similar regulations? Can AC 23-27 be used to justify replacing an old impossible to find part on a certified Canadian airplane?

[PilotDAR]

A Canadian aircraft is required to comply with the CAR's. Though FAA AC's can provide useful background, compliance with the CARs is required. CAR's Standard 571.06, and in particular paragraph (5) states the Canadian equivalent of the FAA AC you have identified. Standard 571, Appendix A provides guidance very similar to that found in the FAA AC. Read, understand and apply Appendix A literally in the context of the task you're considering to apply it to.

The FAA AC appears at first glance to be very liberal, but when you read it from the perspective of "do you have the data?", it drives you back to requiring further approval about the same way as 571 does. It is a bit more free with certain specified items (belts, batteries etc.), but if you apply 571 Appendix A to your question about these, you could find yourself at the same endpoint as the FAA AC could have taken you anyway. "Data" is surprisingly hard to get. It's not a photocopy of the installation instructions and drawings from an STC, it's the STC holder's test reports and design data, which is not commonly released to anyone.

That said....

The present Transport Canada approval system lacks a lower threshold equivalent to the FAA "Field Approval". Now the FAA Field Approval definitely has some potential weak spots (which is why they sometimes get added scrutiny when an N plane with "337" mods is imported to Canada), and the TC serialized STC may be rather overkill for some very simple repairs and changes, particularly since the TC application fee was more than doubled this past summer. TC lacks somewhere in the middle for these situations, and aging legacy airplanes will more and more show the need for this. An sSTC would be too costly overkill, but some qualified oversight is appropriate. Some TC staff are aware of this need, and not resistant to to the notion of an additional path. But, it seems that TC lacks the internal resource and inertia to continue toward this (note that I wrote chose the word "continue" rather than "start" [down this path]). I hope that the AME association will devote a little of their resource to help TC see the light on this subject.

In the mean time, 571 is your friend, along with a heart to heart chat with your friendly TC Inspector. sSTC's and RDA's are available, but may be overkill....

[digits_]

Thank you, that's exactly what I was looking for!