Approved Magnetos for a Grumman Tiger aa5b

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    • February 11, 2019 at 11:33 #12206
      Mike Mackay
      Participant

      I am partners in a 1977 aa5b Tiger. I was told by an A&P that the Slick mags currently on the airplane are “illegal”. I asked our long time mechanic about it and he said that Slick mags have been used on the aa5b for years. He sent me Lycoming Service Instruction (No. 1443J) which lists the Lycoming engines approved to use Slick mags and which includes our engine, an O-360-A4K. However, there is a disclaimer included in the Service Instruction warning that some airframe configurations cannot use Slick magnetos and to consult the airframe manufacturers approved data and type certificates to make sure Slick mags can be used. Is an STC still required for the Slick mags to be approved for use given the Lycoming Service instruction? Our mechanic also said that the Slick Mags are shown in the aa5b parts manual as an available replacement part.

      Can anyone shed any light on how to resolve this issue? The Lycoming Service Instruction is attached.

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    • February 12, 2019 at 08:30 #12208
      Roscoe Rosché
      Keymaster

      Looking at the TCDS for the Lycoming O-360-A4K we see under note 9, for the A4K Slick magnetos which are now the 4371 left impulse coupled, and the 4370 right magneto. No STC required. I have only seen one Lycoming engine with Bendix magnetos, all others have slicks in Grummans.

      FYI

      Roscoe

    • February 20, 2019 at 18:56 #12238
      Fred A. Berardo
      Participant

      I have a 79 Tiger it has Slick mags #4370 & #4371 no problems runs great.

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    • February 22, 2019 at 21:36 #12242
      Mike Mackay
      Participant

      Thanks for the response, Guys.

    • March 5, 2019 at 11:27 #12300
      Scott M
      Participant

      I have a 4371 on the left and I had a 4051 on the right that was still working. I bought a rebuild 4370 from QAA. They wont accept my 4051 as a core because its too old. Does anyone know if the coil is the same as the one used on the 4300 series ? If so I could at least save that. Coils are very expensive and can fail at anytime.

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