A question for IA's and other smart mechanics:
Some helicopter special ops have camera mounts installed per an STC using a 337, a few days later they will remove the mount with another 337 and return the aircraft to original. Over the course of a year or two this same mount may be installed and removed 20 - 25 times or more. Question: If nothing else has changed, is it permissible to sign off the installation in the log book by referencing the original 337 instead of submitting a new one each time it's installed and each time it's removed.
Or, is there a better way to do this? Some aircraft have seats removed and a litter or stretcher installed and removed on a regular basis, do they use a new 337 each time? How about float planes when the floats come on and off?
I can't find anything in the regs that specifically permit or prohibit referencing a previous 337.
Thank you in advance for your input.