Mandatory Service Bulletins: Are they really mandatory?

Are they really mandatory? By Joe Escobar Is a manufacturer's mandatory service bulletin mandatory or not? This topic pops up in hangars regularly and tends to polarize A&P's and IA's alike. They either feel strongly that they are or they are...


Mandatory Service Bulletins

Are they really mandatory?

By Joe Escobar

Is a manufacturer's mandatory service bulletin mandatory or not? This topic pops up in hangars regularly and tends to polarize A&P's and IA's alike. They either feel strongly that they are or they are not (with the majority believing they are not). There does not seem to be a middle ground.

Looking to the past
Perhaps the best way to start out this discussion is get a perspective of past regulations and conformance practices. A Charles Taylor recipient from my area shared the following with me about his experiences as an A&E mechanic:

What checklist to use?


According to 14 CFR Part 43, a mechanic or IA needs to use a checklist when performing an annual or 100-hour inspection. If the aircraft manufacturer has a checklist available, must it be used or can a checklist based on Appendix D of part 43 be used? Technically, according to the regulation either one can be used. But consider this: A Baron had a gear up landing. The investigation revealed a failed gearbox. The maintenance records indicated that a checklist based on Appendix D of Part 43 was used to perform recent annuals. The manufacturer's checklist shows the mechanic how to inspect and service the gearbox, while Appendix D of Part 43 does not. The gearbox had more than 3,200 hours without any documented servicing. TBO on the gearbox is 2,000 hours.

"I would go to work about two hours before everyone else, so I stopped by the post office and picked up the mail. The CAA sent out an AD note to registered owners of the same type airplane whenever any serious defect was discovered. The school I worked at had a subscription to the current aircraft specifications from the CAA, and service information from each of the airplane manufacturers, so we could keep our airplanes current. I would sort it all out and read everything with my morning coffee. By the time I was ready for my second cup of coffee, the boys had the airplanes out on the line and I would go out and check each and every one of them before they were flown every day.

I would immediately take care of any write-up a pilot made, and every 25 hours of flight time I would inspect the engine, clean and gap the spark plugs, change the oil and clean the screen, check the tires for wear and proper pressure, and check and lubricate the flight controls. If we received an AD in the mail, I would immediately do whatever the AD said.

Once every 12 months I would bring each airplane into the hangar for a periodic inspection, a very detailed inspection and specification update. I thoroughly cleaned the airplane inside and out, complied with all the current service bulletins and verified that the airplane conformed to its current aircraft specifications. When I was done, I would prepare a periodic inspection report for the CAA safety inspector and he would come out and issue the airplane a new airworthiness certificate."

That Charles Taylor recipient was the source of all knowledge at the small airport where he worked. Everyone looked up to him and respected his judgment, especially the pilots. Only he could say when an airplane was ready to fly. He always says, "Base your decisions on regulations, not on someone else's opinion."

Influences on perception
It is well known that our environment influences our perception. What we are is based on where we were when we started learning. If you take a look around your local FSDO, you may notice that many FAA inspectors have military backgrounds. The military and major airlines are organizations. An organizational background produces organizational thinking and since the organization owns the aircraft, the ownership responsibilities become functional responsibilities within the organization rather than the responsibility of one individual.

Within the military, organizational thinking becomes authoritative thinking. There's a chain of command, and if you're not in the chain of command, you have no authority. Any question becomes a matter of who has the authority.

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