76-01-04 MCDONNELL DOUGLAS: Amendment 39-2489. Applies to Model DC-9-30 and -50 Series Airplanes Fuselage Numbers 757, 763, 780 through 795, 797 and 798, certificated in all categories. \n\n\tCompliance required within the next 50 hours' time in service or 5 days whichever comes first after the effective date of this AD, unless already accomplished. \n\n\tTo prevent manually induced longitudinal proposing aggravated by the elevator boost system accomplish the following: \n\n\tRemove the hydraulic bleed stop assembly, P/N 4934616-1, per Douglas Alert Service Bulletin A27-176, dated December 13, 1975, or later FAA-approved revisions, or an equivalent procedure approved by the Chief, Aircraft Engineering Division, FAA Western Region. \n\n\tThis amendment becomes effective on January 15, 1976.