74-12-03 MCDONNELL DOUGLAS: Amendment 39-1858. Applies to DC-8-61F, -62F, -63F convertible freighter airplanes, certificated in all categories. \n\n\t(1)\tFor all aircraft in the passenger configuration, within twenty-four (24) hours of receipt of this telegram, or prior to further flight, whichever occurs later, unless already accomplished within the last 50 hours, perform the passenger oxygen system leak check per paragraph 1(a) DACO Alert Service Bulletin A35-25 Revision A dated May 10, 1974, or later FAA-approved revisions. If the oxygen system does not pass the leak check, inspect, repair and replace worn piping as required, and replace broken and missing supports prior to next flight; repeat leak test per DACO A.S.B. A35-25 Revision A, paragraph 1(a). At intervals not to exceed 50 flight hours visually inspect for worn oxygen piping, replace as necessary, and conduct the leak test per DACO A.S.B. A35-25 Revision A, paragraph 1(a) until the modifications described by DACO A.S.B. A35-25 Revision A, paragraph 1(b) have been accomplished. Within 300 hours time in service after initial leak check, secure all oxygen piping, per DACO A.S.B. A35-25 Revision A, paragraph 1(b). \n\n\t(2)\tFor aircraft in the full freighter configuration, prior to further flight after receipt of this telegram, close the oxygen hand shutoff valve on the passenger system and placard system inoperative until (1), above, is accomplished. Prior to conversion to passenger configuration, perform checks, repair, and modifications of (1) above. Paragraph 2, DACO A.S.B. A35-25 Revision A covers this subject. \n\n\tThis amendment becomes effective June 6, 1974, for all persons except those to whom it was made effective immediately by telegram dated May 11, 1974.