Airworthiness Directive: 124 
Date: September 7, 2001 
Subject: S-7 Trim Tab Flutter
Compliance: Mandatory
Models Effected: S-7 Courier from Serial Numbers 85002 Thru 0396181.

Cost: None

A report of trim tab flutter on S-7's equipped with cable and spring systems require the spring to be removed and a stiff link to be installed. This is a temporary solution as a permanent solution is being developed.

Please remove the spring and install a stiff link as show below. The link can be fabricated from 1/8" aluminum sheet. Adjust the length to match to the spring length when plane is at cruise speed with two onboard. Make additional links until the desired trim setting is reached. 

Thank you for your attention to this matter. Hopefully we have not inconvenienced you to any great degree. Fly safe!