46-14-02 FAIRCHILD: (Was Mandatory Note 4 of AD-724-2.) Applies to Models M- 62A3 and M-62A4 Aircraft.
Compliance required immediately.
The aluminum alloy cockpit heat control valve box and valve must be replaced with a valve and box made of ferrous metal at least 0.018-inch thick. If ordinary steel is used, it should be suitably protected against corrosion. In lieu of the foregoing it will be satisfactory to remove the valve box to seal the opening in the firewall with an overlapping sheet of ferrous metal secured with the present bolts and nuts.
(Fairchild Service Bulletin No. 45-62-10 dated July 9, 1945, covers this same subject.)