OEM vs PMA
FAA-PMA parts are often not equal replacements for the OEM parts. They may serve the same function however the service life can be reduced due to poor design. Note the difference in construction between the units below. The difference in construction can result in a catastrophic failure of the exhaust. The OEM originally used 2 formed shells to build the parts while the aftermarket PMA uses fillet welded tubes. Formed tooling is quite expensive, the parts are originally designed to carry the load through parent material rather than through welded joints.