Stabilizers

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FAA Aircraft Certification Service SPECIAL AIRWORTHINESS INFORMATION BULLETIN SUBJ: Stabilizers SAIB: CE-05-27R1 Date: September 6, 2007 This is information only. Recommendations aren’t mandatory.

Introduction

This Special Airworthiness Information Bulletin informs you of a potential problem with foam-filled elevator trim tabs and foam-filled elevator trailing edges on Cessna airplanes listed in Table 1. The foam in the tabs and elevator trailing edges may soak up moisture, cause internal corrosion, and add weight, which could lead to vibration. It has been determined that no regulatory action is necessary because the airworthiness concern does not meet the criteria for an FAA airworthiness directive (AD).

The following airplanes were manufactured with foam-filled elevator trim tabs and foam-filled elevator trailing edges:

Table 1 Model Year Serial Numbers Cessna P206 1968 through 1969 P206-0420 through P206-0603 Cessna P206 1970 P20600604 through P20600647 Cessna U206 1968 through 1969 U206-0915 through U206-1444 Cessna U206 1970 through 1986 U20601445 through U20607020 Cessna 207 1969 through 1984 20700001 through 20700788 1960 57001 through 57575 Cessna 210 1961 through 1984 21057576 through 21064897 Cessna T210 1966 through 1969 T210-0001 through T210-0454 Cessna P210 1978 through 1983 P21000001 through P21000834

Background

Cessna discontinued foam-filled elevator trim tabs (part number (P/N) 1234628-1) in 1985. However, we still receive reports of corrosion problems on airplanes that have these foam-filled tabs installed. Moisture can cause internal corrosion between the tab and the foam. For example, moisture condenses in the tab when the airplane is flown high enough that the surrounding air is cold as normally aspirated and turbocharged airplanes would experience. When the skin of the trim tab becomes thin enough due to the corrosion, the actuator can pull the fasteners through the skin and disconnect. When this occurs, it could separate itself from the elevator. Vibrations in the tail section have been reported, and, during one incident, a portion of the elevator was torn away with the trim tab.

Mandatory Cessna Service Bulletin (SB) SEB85-7, Revision 1, dated February 12, 2007, includes information about inspecting elevators and trim tabs within the next 100 hours or during the annual inspection. Further information is provided in Advisory Circular (AC) 43-16A, Aviation Maintenance Alerts, Alert No. 341, December 2006, pages 5 and 6. The Cessna Pilots Association (CPA) weekly newsletter, CPA ATIS, Vol. 7, Issue 49, Thursday, December 9, 2004, provides information on how to

2 detect the corrosion and what is involved in replacing the foam-filled tabs. See also, CPA Magazine for March and May 2005, pages 7730, 7731, 7840 and 7841.

A review of the FAA service difficulty reports (SDR) database since 1974 reveals 70 reports involving foam-filled tabs. A review of past issues of AC 43-16A and its predecessors found 16 articles published from 1983 through 1999 on this problem.

Cessna has sold 498 replacement trim tabs in the past 4 years. Cessna built more than 16,000 airplanes with foam-filled elevator trim tabs and foam-filled elevator trailing edges.

Recommendations

We recommend that you replace foam-filled elevator trim tabs, P/N 1234628-1, with “unfoamed” tabs, P/N 1234665-1 or 1234665-9 with doublers 1234666-1/-2, per Cessna Service Bulletin SEB92-1, dated January 17, 1992, or an FAA-approved equivalent replacement. Note that elevator trim tab, P/N 1234665- 10 (unfoamed), should comply with Mandatory Cessna SB SEB00-6 dated July 31, 2000.

The drawing for P/N 1234667-1 has now been released. This part replaces P/N 1234000-7 that was used on Cessna 210 models built during 1960-63. At this time, Cessna service information is not available. Whenever a customer orders a trim tab from Cessna Parts Distribution 2 (single engine airplanes), a non- foam filled tab will be provided.

We also recommend replacing foam-filled elevators trailing edges with unfoamed elevator trailing edges as follows:

1. Replace P/N 1234620-16 right hand outboard trailing edge with 1234660-4.

2. Replace P/N 1234633-4 right hand inboard trailing edge with 1234660-12.

3. Replace P/N 1234633-15 left hand trailing edge with 1234660-3.

For Further Information Contact

Gary D. Park, Aerospace Engineer, FAA Wichita ACO, 1801 Airport Road, Room 100, Wichita, KS 67209; phone: (316) 946-4123; fax: (316) 946-4107; e-mail: [email protected].

(Optional) For Related Service Information Contact

Cessna Aircraft Company; Product Support, P.O. Box 7706, Wichita, Kansas 67277, (316) 517-5800, Facsimile (316) 942-9006