74-14-07 SIERRA ENGINEERING CO: Amendment 39-1895. Applies to Sierra Engineering Company Model 289-601 series passenger oxygen masks installed in aircraft certificated in all categories, including, but not limited to DC-8, DC-9, DC-10 and L-1011 aircraft. \n\n\tCompliance required within one year after the effective date of this AD, unless already accomplished. \n\n\tTo prevent separation of the reservoir from the mask facepiece, accomplish the following: \n\n\t(a)\tInstall a retaining disk to secure the reservoir to the facepiece on Sierra Model 289-601 series passenger oxygen masks in accordance with Sierra Engineering Company Service Bulletins No. 289-601-35-1, dated February 11, 1974, and No. 289-601-35-2 dated March 1, 1974, or later FAA-approved revisions. \n\n\t(b)\tEquivalent installations may be approved by the Chief, Aircraft Engineering Division, FAA Western Region. \n\n\t(c)\tAircraft may be flown to a base for the performance of that maintenance required by this AD per FAR's21.197 and 21.199. \n\n\tThis amendment becomes effective August 15, 1974.