Hello Walt, First I want to thank you for all the great tows when I was working on my CFIG back in February. If you want to send your letter to the FAA, and it sounds as if you will, you might want to take some precautions. In the 40+ years I flew for a living only 3 or 4 pilots contacted the FAA with safety concerns. To be fair we had other avenues, i.e. Union, etc to air our grievances. But a few did go to the FAA and later had regrets. If they pursue your concerns you may be asked some hard questions. Did you report the incident? To whom did you report the incident? Employer, NASA, FAA, SSA, or anybody else? Did you do a proper preflight of the tow hook? There will be many other questions but I think you get my point. They will be thorough and you will feel as if you are in crosshairs. And you will be in the crosshairs. Before you put a stamp on it get some advice from an aviation lawyer. AOPA has a great legal staff. I would trust their opinion on how to approach the FAA before listening to anyone else. Good luck.