Bendix Mag AD

[170C]

Can someone clarify the Bendix Mag AD 2005-12-06? 250 hour ago I had both mags gone through by a shop. Both had coils, points, etc replaced. On one of them they noted, "complied with AD 2005-12-06" I am sure that that one had the impulse coupling checked per the AD and it passed. The second one ended up having a new snap ring cam assy installed. I think this was because that one likely didn't pass the AD requirements. On the second one with the new snap ring cam assy------when will it require another inspection? It has 252 hours on it since the repair. ON the first one that doesn't have the new snap ring camp assy (it too has 252 hrs since being repaired/inspected), when will it need to be inspected again?

[Bruce Fenstermacher]

I'll make this as clear as I can. This AD DOES NOT APPLY to your aircraft unless you have a Lycoming AEIO- 540, HIO-540, IO-540, 0-540, and TIO-540 series engine installed.

Since I'm pretty sure Frank that you don't have one of those engines, you can forget you ever heard or read about it this AD. So there is no mandatory maintenance or inspections required of your mag.

Now that we have made that clear. Regular mag maintenance and inspections are a good idea. I'd have my mags inspected about every 500 hours in service.

[Brad Brady]

I'll make this as clear as I can. This AD DOES NOT APPLY to your aircraft unless you have a Lycoming AEIO- 540, HIO-540, IO-540, 0-540, and TIO-540 series engine installed.

Since I'm pretty sure Frank that you don't have one of those engines, you can forget you ever heard or read about it this AD. So there is no mandatory maintenance or inspections required of your mag.

Now that we have made that clear. Regular mag maintenance and inspections are a good idea. I'd have my mags inspected about every 500 hours in service.

Bruce is correct, I might introduce my personal idea five years (or five hunderd Hrs) is to long, to look at the internal parts of a mag......Just my opinion......Brad

[170C]

Thanks guys! I checked my log book and found that my then IA did comply with a Bendix service bulletin SB 599B regarding inspection of impulse couplings. (This was back in 1996 as I recall) Whether real or imagined I have been operating under the assumption that those impuse couplings were to be inspected either every 250 or 500 hours to determine the amount of wear on the rivets that secure the impulse "paws". When both mags were inspected/repaired at the 500 hour time some 252 hours back, the reason for one of the cam assy's being replaced, I thought, was due to wear on those rivets. Anyway, the mag repair shop mentioned that the mag that didn't have the cam assy replaced should be checked again in ??? hours of service and I couldn't recall if it was 250 or 500 hours and I apparently misunderstood that that inspection was as a result of either a SB or AD. Now it appears it was just a (sound) recommendation and thus at my next annual in May I need that mag to be checked.

[Bruce Fenstermacher]

Frank there WAS an AD that required this inspection. It was superceded in 2005 by AD 2005-12-06. So while it is not required now, it is probably a good idea which is what Brad and I are trying to say.

[ronjenx]

AD 2005-12-06 supersedes AD 96-12-07, Amendment 39-9649.

AD 96-12-07, Amendment 39-9649, made mandatory the 500 hour inspection that is in the TCM S-20/S-200 Service Manual.

AD 2005-12-06 came out, cancelled the previous AD, and dropped the requirement for all but the Bendix mags on the Lycoming 540 series engines.

The "when" in the manual is now not mandatory. As stated above, it's a good idea to inspect anyway.
The snap ring impulse coupling inspection is every 500 hours.
The riveted impulse coupling inspection is 100 hours.
The one point in the manual I would ignore is their statement that all mags must be overhauled at the expiration of 4 years since the last mag overhaul without regard to engine operating hours. That's just my opinion, though.

The "how to" in the manual is mandatory once you start working on the mag.