Aircraft
Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration
CE-11-29 R1
September 27, 2011
This is information only. Recommendations
aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin (SAIB) informs
registered owners/operators of Cessna Aircraft Company (Cessna) 414A
and 421C aircraft with S-TEC Corporation (S-TEC) Supplemental Type
Certificate (STC) SA08996AC-D (system 55/55X) with optional Trim
installed, Cessna 414A and 421C aircraft with S-TEC STC SA7787SW-D
(system 65) with optional Trim installed, and Cessna 414A and 421C
aircraft with S-TEC STC SA7790SW-D (system 60) with optional Trim
installed, of an airworthiness concern. Specifically, this SAIB
provides guidance on procedures for inspection of the rudder trim tab
blocks which were relocated during the installation of the STC. This
SAIB also provides guidance on inspecting phenolic blocks for wear
along the flight control system.
At this time, this airworthiness concern has not been determined to be
an unsafe condition that would warrant airworthiness directive (AD)
action under Title 14 of the Code of Federal Regulations (14 CFR) part
39.
This SAIB has been revised to incorporate the changes to S-TEC Service
Bulletin (SB) 11-001, removes the reference that Cessna may take
similar action, and notifies operators that STCs SA08996AC-D,
SA7787SW-D, and SA7790SW-D have been revised to incorporate the changes
recommended in this SAIB.
Background
During an inspection of an elevator trim installation per S-TEC STC
SA08996AC-D, it was found that the elevator trim cables pass through a
bulkhead with about five degrees of deflection. A phenolic block is
installed to prevent wear on the bulkhead and cable. Additionally, the
cable impacts the floor aft of the bulkhead. A phenolic strip is
installed to prevent contact between the cable and the floor. Until
recently, there were no directed inspections of the phenolic block and
strip.
The S-TEC STCs have been revised to install pulleys to move the cables off the bulkhead pass through.
Also, during the installation inspection, it was noticed that the
rudder trim tab blocks were not properly relocated in accordance with
the S-TEC STCs. This prevented the rudder system from obtaining full
travel. There was no approval for the location and installation of the
trim tab blocks for this particular installation.
Recommendations
The Federal Aviation Administration (FAA) recommends you inspect your
rudder trim tab blocks and flight control cables in accordance with
S-TEC Service Bulletin (SB) 11-001R2, dated June 28, 2011. If during
the inspections listed in the SB, it is determined that the rudder trim
tab blocks were not relocated in accordance with the STC, they must be
relocated in accordance with the STC as reflected in paragraph 3 of SB
11-001R2 or any other method which is approved by the FAA. The FAA also
recommends you modify your installation to include the changes made in
the updated STC which include the installation of the pulleys to move
the cables off the bulkhead pass through.