I'm not an A&P/IA, so I could be wrong about what most IA's would do, faced with an invalid Airworthiness Certificate!
I would say that the Airworthiness Certificate is the most important single document on the aircraft, ahead of any other documentation, and is likely one of the first things checked on any annual inspection. I think very few IA's would be likely to inquire of the FAA about it's validity, though! If there is no Airworthiness Certificate, or it's validity is in question, how could anyone legally release an aircraft for flight? Would any of you IA's sign off an aircraft known to have an invalid Airworthiness Certificate, releasing it for flight at the owner's discretion? After all, it is the pilot who is ultimately responsible for determining airworthiness of the aircraft!
It's important that I say I do not believe that Chris or anyone else knowingly did anything wrong in signing off Chris's plane! This situation could just as easily have happened to me.
