Yes Gary I completely agree. I sometimes forget that my own 170A with what was described as 170B wings in the logs, but turned out to be L-19 wings, had a lot more going on in the changed from original department, making a one time approval on a 337 more inviting for the mechanic.n2582d wrote:Bruce,
I agree that such a swap should be done in consultation with one's local FSDO but I doubt if it would require a 337 form. In this case one is replacing the same part number, not going to a later or different Cessna model wing. It is not a major alteration or repair which is what a 337 form would be used for. Might it not just require a logbook entry detailing the swap? One catch might be how the airframe logbook total time is calculated. Say you put an 8000 hour wing on a 3000 hour fuselage. Do you now include "wing total time" and "fuselage total time" in every logbook entry?
If I was actually doing this myself, swapping a 170B wing with a 172 wing, I'd be going out of my way to show that the new assembly is actually a part for part replacement of the old assembly and thus only a minor alteration. This is pretty easy I think. the 170 right wing assembly for example is 0523005-1. This is the same part number for the 172 initially. But the 172 part manual has a 0523005-200 superseding the original. Basically all wing assemblies for the 172 serial 28000 to 17249544 (or through the G model) and all wing assemblies for the 175, can be shown to be exactly the same as that used in the 170B. It is important to note the fuel system is not part of the wing assembly.
Armed with this information, I'd visit with my mechanic. Don't be surprised if your mechanic wants to visit with the FAA. And before he visits with the FAA, I'd arm him with all the help of support from Cessna that Cessna will give.
In the end I wouldn't be surprised that the repair is documented with a form 337, right or wrong.