user 21975
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- Mar 31, 2021
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I was just reading about a bloke on the (Piper Owner Society) POS site that had an unfortunate incident where one of his magnetos failed in flight. He had relatively recently bought the airplane, had a pre-buy done, then later had an annual inspection completed. Sometime later, he had the mag failure. After safely returning to Earth, away from home base, the local mechanic pronounced the offending magneto "toast." Our intrepid aviator then decided to look into his logs, and discovered that last maintenance done on his magneto was some 1,000 hours ago. He was dismayed to learn it was not flagged by either the pre-buy or the annual.
The reason for this post, is that it got me thinking about my own airplane. As an owner, who also purchased his airplane in the last year, and had an annual...I too, have worked through a bit of confusion over the Magneto AD's vs MSB's. And to highlight the issue for other owners that have not pondered such questions.
Most every owner will at least review AD's applicable to his or her airframe. Easy enough. The IA needs to document their review of applicable AD's for compliance during the annual inspection. They will also document the engine(s). IA's also know they are supposed to document all the accessories (they have enough experience to know what to look for.) Owner's, although ultimately responsible, might not know what to search for. Magneto AD's may or may not be on the engine list of applicable AD's. For instance, my engine, a Continental TSIO-360-KB engine has an AD 81-16-05 that applies to Slick magnetos of the 4200 and 6200 series. That's N/A for me. I have Bendix S6LSC-25P's. If I search for "Bendix" I get a long list of old one time AD's or are only applicable to the D-2000 D-3000 or D-2200 series. So my IA has not flagged any AD's that are due. None recent or repetitive, anyway. My sets were overhauled about 250 hours ago.
What I am highlighting for owners... have you had a conversation with your IA on what is due for your airplane? What is required vs what is recommended?
Does your IA highlight any Mandatory Service Bulletins (MSB's) that are not so mandatory for Part 91 private owners? Engines, airframes, props, other accessories?
Do you ask your IA to perform non-mandatory MSB's or other recommended maintenance items? Do they document accomplishment in your logs?
Have you backed up your IA to make sure your airplane is getting the maintenance it needs? My IA did miss one A/D. Asked him about it because it was a recurring AD and it was documented in the past in my logs (in a different language). He then got it done. It happens.
The only maintenance requirement I can find for my magnetos is TCM MSB 645. THE MSB applies to S-20 series (and others). Mine are S-20 series? Designated Bendix S6LSC-25P. AD's can be very specific, ie I have a PA-34-220T, not a PA-34-200T. Entirely different set of AD applicability. I missed a couple of AD's because I am one or two serial numbers out of the range applicable. Whew! But it seems my -25P magnetos are considered S-20 series. So with the snap ring impulse couplings, per the MSB, each mag needs a recurring 500 hr inspection for wear.
Keep in mind, although I have a recurring 500 hr MSB on my magnetos, as a Pt 91 private owner, the IA is not required to flag it, comply with it, or even tell me about it. Nor would I expect the IA to do so, especially if the owner is asking for a minimum cost annual, or wants the annual done in two days!
So would anyone here be at risk, like the bloke I first mentioned at the beginning of the post?
The reason for this post, is that it got me thinking about my own airplane. As an owner, who also purchased his airplane in the last year, and had an annual...I too, have worked through a bit of confusion over the Magneto AD's vs MSB's. And to highlight the issue for other owners that have not pondered such questions.
Most every owner will at least review AD's applicable to his or her airframe. Easy enough. The IA needs to document their review of applicable AD's for compliance during the annual inspection. They will also document the engine(s). IA's also know they are supposed to document all the accessories (they have enough experience to know what to look for.) Owner's, although ultimately responsible, might not know what to search for. Magneto AD's may or may not be on the engine list of applicable AD's. For instance, my engine, a Continental TSIO-360-KB engine has an AD 81-16-05 that applies to Slick magnetos of the 4200 and 6200 series. That's N/A for me. I have Bendix S6LSC-25P's. If I search for "Bendix" I get a long list of old one time AD's or are only applicable to the D-2000 D-3000 or D-2200 series. So my IA has not flagged any AD's that are due. None recent or repetitive, anyway. My sets were overhauled about 250 hours ago.
What I am highlighting for owners... have you had a conversation with your IA on what is due for your airplane? What is required vs what is recommended?
Does your IA highlight any Mandatory Service Bulletins (MSB's) that are not so mandatory for Part 91 private owners? Engines, airframes, props, other accessories?
Do you ask your IA to perform non-mandatory MSB's or other recommended maintenance items? Do they document accomplishment in your logs?
Have you backed up your IA to make sure your airplane is getting the maintenance it needs? My IA did miss one A/D. Asked him about it because it was a recurring AD and it was documented in the past in my logs (in a different language). He then got it done. It happens.
The only maintenance requirement I can find for my magnetos is TCM MSB 645. THE MSB applies to S-20 series (and others). Mine are S-20 series? Designated Bendix S6LSC-25P. AD's can be very specific, ie I have a PA-34-220T, not a PA-34-200T. Entirely different set of AD applicability. I missed a couple of AD's because I am one or two serial numbers out of the range applicable. Whew! But it seems my -25P magnetos are considered S-20 series. So with the snap ring impulse couplings, per the MSB, each mag needs a recurring 500 hr inspection for wear.
Keep in mind, although I have a recurring 500 hr MSB on my magnetos, as a Pt 91 private owner, the IA is not required to flag it, comply with it, or even tell me about it. Nor would I expect the IA to do so, especially if the owner is asking for a minimum cost annual, or wants the annual done in two days!
So would anyone here be at risk, like the bloke I first mentioned at the beginning of the post?
