59-13-02 PIPER: Applies to Models PA-24 and PA-24 "250" Aircraft Serial Numbers 24-1 to 24-978 Inclusive and 24-980.
Compliance required within the next 100 hours of operation or by October 1, 1959, whichever occurs first.
Service experience indicates that cracks have developed in the aileron balance weight attachment bulkheads. These bulkheads are riveted to the front spar of the aileron and are the supports to which the balance weight arm is attached. To reduce the probability of failure of the aileron balance weight arm attachment install reinforced bulkheads on both ailerons except on Serial Number 24-980 replace the balance weight attachment bulkhead on right aileron only.
(Piper Service Bulletin No. 173 also covers this subject and states "Service Kit, Part Number 734-233, is available from your nearest Piper distributor or dealer free of charge if the airframe serial number is included on the purchase order.")