58-19-03: Carburetor Air Box Rework

58-19-03 MOONEY: Applies to Mark 20A, Items 1 and 3 to Serial Numbers 1201 Through 1275, Items 2 and 4 to Serial Numbers 1201 Through 1257, Item 5 to Serial Numbers 1201 Through 1259. Compliance required by December 1, 1958. Several cases have occurred in which the carburetor air box cross vanes P/N 6235 have cracked and broken off. This type failure could cause loss of power if the vanes are drawn into the carburetor opening. Cracking of carburetor air boxes around the neck has also been reported. The following rework is therefore necessary: 1. Remove the carburetor air box and inspect for cracks. Repair as required by welding. 2. Add an aluminum brace to each side of the air box neck. 3. Remove cross vanes located in air box neck. 4. Shorten fuel overflow drain tube on bottom of air box. 5. Enlarge fuel overflow drain tube hole in bottom of cowl and replace existing grommet. (Mooney Service Letter 20-37 covers this same subject.)