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Output Number
IR19990187
Approval Date
Published Date Time
Recommendation type
Interim recommendation
Mode
Aviation
Date released

The Australian Transport Safety Bureau (formerly BASI)
recommends that Cessna Aircraft Corporation take appropriate action
to ensure that Cessna elevator trim-tab actuator component parts
affected by this safety deficiency are recoded so that they cannot
be purchased separately. In addition, it is recommended that Cessna
Aircraft Corporation review comparable designed trim-tab actuators
to ensure that they are not affected by this safety
deficiency.



As a result of the investigation into this occurrence, the Bureau
simultaneously issues the following safety advisory notices:



SAN19990188



The Civil Aviation Safety Authority should note the safety
deficiency identified in this document and take appropriate
action.





SAN19990189



The US Federal Aviation Administration should note the safety
deficiency identified in this document and take appropriate
action.





SAN19990218



The US National Transportation Safety Board is advised of the
recommendation made to the aircraft manufacturer and safety
advisory notices issued to the Civil Aviation Safety Authority and
the US Federal Aviation Administration.

Organisation Response
Date Received
Organisation
Cessna Aircraft Company
Response Text

In reviewing your Interim Recommendation, Cessna Product
Engineering agrees with the stated recommendation to code the
replaceable components of the actuator assembly such that a matched
set of components, i.e., the male externally threaded component and
the female internally threaded component cannot be purchased
separately from the factory. After looking into the other aircraft
in the 300/400 Series, our engineers have begun to identify a
system in use on all models of Cessna aircraft and not just the
Model 402 for the functions of elevator trim tab, rudder rim tab,
as well as aileron trim tab. We believe that all actuators of this
type and variety should be coded together.



The Cessna Spare Parts Division, CPD-2, will code all suspect
threaded actuator components accordingly once Product Engineering
has completed the task of researching and establishing the
respective parts and/or assemblies with their appropriate
effectivities and high assemblies.



Our engineers have completed the research on the Model 402
aircraft, and will be ready to submit the data to Mr [name] at
CPD-2 Spares early next week. The task is somewhat complex to
identify all of the suspect components, however, we are making
progress in this area. I will be working to ensure the engineers
are able to develop a complete, concise list of actuator assemblies
and the suspect components which must be identified for the
remainder of the 300/400 models.



It is unfortunate many operators are failing to adequately comply
with the warnings and notes in the Maintenance Manuals stipulating
the type of lubricants and the intervals at which service must
occur, as well as the noted components which are recommended to be
replaced as a set during overhauls. Aside from coding the parts,
there appears to be little else that can be done to insure the
operators and maintenance engineers adhere to the guidelines as
outlined in the aircraft service manuals.