It’s highly technical Piper engineering term but here goes: “Onaccountofbecause”
i’what rules? Certificated? Cutting rear seat tubes in the states is a difficult approval. Ask scooter to post a pic or two of his removable tubes. Round tubes, by the way.
Here's the only pic i can find. Saddles made from a round tube. Pins welded to the seat tubes to hold things together. All three tubes come out.
Yes. The top one can be removable for loading, but must be in place for flight. I've found that when my -12 is heavily loaded the pin alignment for the top tube can be ever-so-slightly offset.
