A repair station mechanic writes, “During an Annual inspection (on the Raytheon Beech 58) the inspection department decided to comply with the 500 hour magneto internal inspection, which includes the impulse coupling per Slick (Unison) Service Bulletin 2-80C. One impulse coupling was found to be very loose—due to loose rivets. It would have failed very soon. A failure of this type can cause extensive damage to the magneto and the engine. The aircraft manufacturer’s inspection checklist does not call for detailed inspection of the magneto impulse coupling or other magneto internal parts, other than points. This coupling was replaced with a new part— the old part only had 529 hours time since new. (I) suggest compliance with the 500 hour detailed inspections of all magnetos, regardless of the omission (of said inspection criteria by some airframe manufacturers). All magneto manufacturer’s provide checklists and inspection criteria for their magnetos.” “This station adheres to the 500 hour magneto and coupling detailed inspections and have found parts that do not meet magneto manufacturer’s airworthiness requirements. Many low time in-service units have been found with parts worn beyond limits. This station considers (this level of magneto care to be...) to be another level of safety beyond the airframe manufacturer’s checklist requirements.” (P/N listed is M3050, generating nine additional SDRS data base entries with similar defects.)

Part Total Time: 529.0 hours.