AD 48-18-03

48-18-03 LOCKHEED: Applies to Model 49-46 Aircraft.

Compliance required every 300 hours of operation.

1. Cabin supercharger drive shafts should be inspected at periods not to exceed 300 hours of operation in accordance with instructions and procedures specified in LAC Service Bulletin 49/SB-107, revised November 22, 1946. Concurrent with the foregoing inspection, the rear drive shaft universal joint, clutch end bearing, carbon oil seal and overriding clutch, should be completely overhauled. All defective parts are to be replaced and clutch end bearing 111GE is to be replaced regardless of condition. The sheet-metal retainer (LAC P/N 257643 is to be replaced as soon as practicable with bronze retainer (LAC P/N 299449).

2. The replacement of clutch end bearing 111GE will not be necessary if the supercharger is reworked to provide a double bearing support for the rear universal joint, and overrunning clutch assembly. This rework will also require replacing the present carbon faced oil seal with a slinger type and modify the supercharger housing to suit. The pre-flight inspections for oil seal damage can be dispensed with when slinger type seals have been installed.

(LAC Service Bulletin 49/SB-393 covers this same subject.)