<p><strong><font color = "blue">Cessna: P206—P210 <em>(see list </em>); Elevator Trim Tab Corrosion; ATA 5523</font> </strong></p>
<p><em>(The following safety article is published as received from the Wichita, Aircraft Certification Office. Specified models include P206, U206, 207, 210, T210, and P210.) Contact information is found at discussion's end.)</em></p>
<p>“FAA Special Airworthiness Information Bulletin (SAIB) CE-05-27, dated January 20, 2005, informed owners and operators of Cessna 206/207/210 airplanes of a potential problem with foam-filled elevator trim tabs. The foam may soak up moisture and can cause internal corrosion. Parts of the elevator have been lost, and reports of vibration in the tail have been reported for airplanes with and without internal foam. Due to corrosion, the area of the trim tab near the trim tab actuator can become very thin, and cause the actuator to become disconnected from the tab. If this occurs, the tab may vibrate or possibly flutter. Such an occurrence may also develop from the accumulation of moisture in the foam causing the elevator to become under-balanced. This has also been known to occur with trim tabs that were not foam-filled but with water or ice collecting inside.</p>
<p>“As an example of the years of concern by the FAA on this issue, General Maintenance Alert Bulletin No. 62, ‘Maintenance of Control Surfaces and Systems for Flutter Prevention,' dated August 24, 1953, informs </p>
<p>maintenance technicians about proper maintenance procedures to prevent flutter by retaining ‘water-tightness.' High unbalance due to trapped water or ice within the surface can cause flutter. Proper control surface balancemust be maintained.</p>
<p>“In the SAIB we recommend replacing foam-filled elevator trim tabs (P/N 1234628-1) with ‘un-foamed' tabs (P/N 1234665-1), or (P/N 1234665-9) with doublers (P/N 1234666-1/-2) per Cessna Service Bulletin SEB92-1, dated January 17, 1992, or an FAA approved equivalent replacement. Also, note that elevator trim tab (P/N 1234665-10 – un-foamed) should comply with mandatory Cessna Service Bulletin SEB00-6, dated July 31, 2000, requiring the installation of additional rivets. We further recommend periodic 100 hour and annual inspection of the trim tab and surrounding area.</p>
<p>“Information is available to address problems with foam filled tabs in the Cessna service bulletin and their maintenance and service manuals, FAA Advisory Circulars (AC) such as AC 43.13-1B (Chg. 1), AC 91-60, AC 91-56A, AC 20-103, AC 135-10A, AC 135-7, AC 135-3B, AC 43-9C, AC 121-1A, AC 120-84, AC 43-4A, other AC 43.16A; and the SAIB. The inspections of the foam filled trim tabs require scrutiny to determine if delamination of the upper and lower surfaces of the tab has occurred or if the paint bubbles. Whether or not the trim tab is foam filled, trim tabs must be periodically inspected for corrosion, security, and damage to continue to be airworthy. Cessna Service Bulletin SEB85-7, dated April 5, 1985, includes information about inspecting elevators and trim tabs. Cessna manual D5121-1-13, ‘200 series continuous airworthiness program' is available.</p>
<p>14 CFR Part 91 requires that aircraft be airworthy to be operated, that owners and operators are responsible to maintain aircraft in an airworthy condition, and that the aircraft undergo annual inspections.” </p>
<p><em>(For further information contact Aerospace Engineer, Mr. Gary Park, Wichita Aircraft Certification Office, 1801Airport Road, Room 100, Wichita, KS 67209; 316-946-4123.) </em></p>