WACO YMF F5 Series, Maintenance Manual

Page: 286 / 401

SERVICE BULLETIN
WACO Classic Aircraft Corp.
2850 Territorial Rd. West
Battle Creek, MI 49015
WACO CLASSIC CONSIDERS
COMPLIANCE MANDATORY
SB10-01
Released: 07/21/2010 Page 1 of 4
Rev: IR
SUBJECT: ELEVATOR CABLE WEAR DUE TO CABLES BECOMING
SLACK
MODELS AFFECTED: SERIAL NUMBERS AFFECTED:
YMF WACO F5A F5001 thru F5009
YMF WACO F5B F5010 thru F5036
YMF WACO F5C F5C040 thru F5C122
COMPLIANCE TIME:
Initial compliance before the next flight by inspection as described in Instruction
#1 below. At the next 100 Hr or Annual Inspection, compliance with Instruction
#2. Following compliance with Instruction #2, no further action is required.
APPROVAL:
The technical content of this Service Bulletin has been shown to comply with the
applicable Federal Aviation Regulations and is FAA approved.
PURPOSE:
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 (see Fig. 1) 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.
Fig. 1
Elevator Cable Pulleys at Station 212