Aircraft
Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration
CE-08-33
July 10, 2008
This is information only. Recommendations
aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin is being issued to
alert all aircraft manufacturers, distributors, dealers, engine
overhaul facilities, owners and operators that have or use Slick
Aircraft Products aircraft magnetos of service problems with carbon
brushes installed in these magnetos.
Background
Unison Industries (Owners of Slick Aircraft Products) manufactures a
series of magneto ignition systems that are widely used on the general
aviation reciprocating engine fleet. It is known that Unison magnetos
are installed on, but not limited to, Textron Lycoming and Teledyne
Continental series engines. Numerous aircraft makes and models are
potentially affected.
There have been field reports of premature wear of the carbon brushes
in a certain serial number range of magnetos. Premature brush wear
could lead to failure of the magneto to provide consistent spark, which
could result in possible loss of engine power. The actions required by
Unison Industries Service Bulletin SB3-08 do not provide a solution or
terminating action. The actions specified in the service bulletin are
intended to detect signs of wear before damage grows, which could
result in magneto failure. The service bulletin will be updated when
terminating action is implemented by Unison. Meanwhile, the service
bulletin inspection requirements will remain in effect. In addition,
there may be additional inspection requirements or other corrective
actions defined by your respective engine and aircraft manufacturer’s
service information concerning this service difficulty issue.
At this time, this airworthiness concern is not considered an unsafe
condition that would warrant an airworthiness directive (AD) action
under Title 14 of the Code of Federal Aviation Regulations (14 CFR part
39).
Recommendations
The FAA recommends compliance with Unison Industries Service Bulletin
SB3-08. We also recommend that aircraft owners and operators become
familiar with the relevant engine or aircraft service information
concerning this service issue. Pilots and mechanics should pay close
attention to the results of a magneto ignition check before each flight
or while performing aircraft maintenance.
For Further Information Contact
Mr. Chung-der Young, Aerospace Engineer, Chicago Aircraft Certification
Office; 2300 E. Devon Avenue Des Plaines, Illinois; phone: (847)
294-7309; fax: (847) 294-7834; e-mail: chung-der.young@faa.gov.