Pressurized Magnetos

Out of Sight… Out of Mind?

Magnetos, especially pressurized magnetos, require a consistent and routine approach to proper maintenance. Operating procedures and conditions for a particular magneto can and do vary greatly. Slick recommends an inspection every 100 hours, which is also consistent with the section of AD 88-25-04 pertaining to aircraft being operated for hire.

You should review the AD with your mechanic. It pertains to moisture within magnetos. The AD requires aircraft operating under FAR 91 to have the magnetos checked at each annual. The slick service manual calls for complete service of the magnetos every 500 hours. Slick warranty is void if the prescribed maintenance schedules are not followed.

Especially noteworthy are the 100 hour inspections of the magneto air supply filter. Slick recommends replacement of the air supply filter at 250 hours. RAM recommends that aircraft operating in salt air coastal environments have the filter replaced more frequently, such as at the regular engine oil change interval. RAM offers an improved in-line air filter which has a moisture drain hole and drain tube added. It is a Balston “microfibre filter tube.” It is also available through RAM’s Parts Catalog Sales Department as RAM P/N 1396-2. Overhaul of Slick magnetos is required at engine TBO or “when conditions indicate.” This could be during one of the 100 hour inspections, or the 500 hour service. RAM’s policy is to replace old magnetos with New Slick magnetos featuring numerous improvement benefits. These improvements are reviewed in RAM’s Parts Catalog. Proper magneto overhauls involve close to two dozen parts, time consuming labor and exacting pressure testing. If necessary to field overhaul, it is approved by Slick only if all the prescribed items are replaced with Slick manufactured service parts; however, the Slick warranty does not extend to magnetos unless they are rebuilt at Slick.

RAM recommends following the prescribed service and maintenance outlined in Slick SB1-88B, SB2-80C and the latest issue of Slick’s Maintenance & Overhaul Manual. RAM recommends installing new magnetos when extensive overhaul appears necessary.