47-10-30 LOCKHEED: (Was Mandatory Note 33 of AD-763-3.) Applies to Model 49 Serials 2047 Up to and Including 2075 and to Serials Prior to 2047 Which Have Had 68092 Surge Box Flapper Valves Replaced by 285750 Valves in Accordance With Lockheed SI-15, Dated June 18, 1946.
Compliance required prior to April 1, 1947.
Replace fuel tank surge box flapper valves, LAC P/N 285750, with new type valve, LAC P/N 285750-600.
(LAC Service Instructions 49/SI-15, revised August 10, 1946, and 49/SI-15A, revised August 3, 1946, or subsequent, cover this same subject.)