The International Cessna^® 170 Association

We just took our Bendix S6LN-21 Mags in for a 500 hour inspection. One was orginal and one was a remanufactured on. The orginal one we were told that the rotor magnet need to be replace due to a AD out on it. I searched the FAA web for any AD referring to the rotor magnet for this mag and came up with nothing. I tried to even find a Service letter or bulletin relating to this and have come up with nothing. Does any one know what the AD number is or is the guy doing our 500 hour giving us a lot of garbage

Thanks
Doug
P.S thanks to all who helped with the info for doing the 337 on getting approval on our 0-300B

Hi,

That's a pretty old issue. The current AD number is 94-01-03 (R1 I think). The TCM/ Bendix service bulletin is MSB644. I hope you find that this has already been taken care of.

Mark's right, althow its (R2) now. I just went through this last week on a Citabria. Had to remove and inspect the mags because the mags wern't marked as per MSB644 and no log book entries stating that the magnets were good (they were). And life goes on.

Ask for a reference for requiring a 500hr check?

Yes as stated there is an AD which requires the replacement of certian magnets. There is a picture in the service manual of a good and bad magnet. Using this it would be easy to see for yourself which one you have.

Last year I was looking to replace a rotating magnet after a bearing failure destroyed one. Basically you can't buy one unless you are willing to pay more than a whole rebuilt mag would cost for just the magnet. If you have time and you know what your looking for you can find good magnets cheap occasionally. I found 2. One I got for nothing but it was destroyed before I could use it which is a long story and the second one I payed $45 for on eBay 3 months after I'd already replaced my Bendix with new Slicks. No it's not for sale as I will rebuild that mag some day.

While it is good to inspect mags about every 500 hours, and the magnet is a good catch and one you can not put back in service now, Tim is right. Ask the mechanic to see the requirement the mags where required to be checked in the first place. There isn't any.

It's possible that a particular inspection form arbitrarily calls for a 500 magneto inspection, expecially if it's one used by a Certified Repair Station (CRS). If an owner submits his aircraft to a facility and authorizes an inspection based upon the CRS inspection forms, then the inspection must be performed.

There definitly is a AD out on the Bendix mags for years. The rotating magnet that had flat sides or brass inserts were to be discarded. OK for air boats. Also the coul had to to be a red one. Although they lasted for years after the AD was out they would develope cracks and ghround out to the case. Tailspintommy