Elevator Cables May Become Slack, Causing Premature Wear

The WACO Classic Aircraft Company has issued a service bulletin for its YMF WACO F5A, SN F5001- F5009; YMF WACO F5B, SN F5010-F5036; and YMF WACO F5C, SN F5C040-F5C122, for elevator cable wear due to the cables becoming slack.

WACO Classic Elevator Cable Pulley Assembly

According to the service bulletin posted on the company's website, the down elevator cable of a YMF WACO F5C has been found to be worn and frayed resulting from a lack of adequate cable tension. It has been determined that due to the in flight forces on the elevator cable system, inadequate cable tension can result in the down cable becoming slack allowing it to come into contact with the stainless steel guard located below the pulley set at aircraft station 212 located approximately 50 in forward of the rudder hinge line in the lower aft fuselage. Although, when properly tensioned, the cable is unlikely to come in contact with the guard, an unsafe condition can develop without the operator being aware. Because this is a possibility, all affected aircraft are to be inspected and modified in accordance with this service bulletin. To prevent possible damage to the elevator cables, a new pulley guard is available that incorporates a Delrin rub strip between the pulley rim and the stainless steel bracket. This rub strip will prevent cable wear should the cable tension not be properly maintained allowing the cables to sag.

On the website, the company has posted illustrated instructions for determining if cables have become too slack for safe operation of the airplane. If it is determined that the airplane needs repair, a new pulley guard is available from WACO Classic at no charge to the owner.

WACO Classic says that all of the airplanes with serial numbers listed above should be inspected before the next flight using the methods described on the website. At the next 100 Hr or Annual Inspection, the necessary repairs, if any, should be made. WACO Classic says the technical content of the Service Bulletin has been shown to comply with the applicable Federal Aviation Regulations and is FAA approved.

FMI: www.wacoclassic.com/pdf/SB10-01.pdf