70-23-01\tBOEING: Amdt. 39-1103. Applies to Boeing Model 747-100 Series airplanes certificated in all categories. \n\tCompliance required within the next 200 hours' time in service after the effective date of this ad, unless already accomplished. \n\tTo prevent failures of the spindle nut, accomplish the following: \n\tReplace the wing gear upper side strut spindle nut in accordance with Boeing Service Bulletin 32-2055 dated October 2, 1970, or later FAA approved revision, or an equivalent method approved by the Chief, Aircraft Engineering Division, FAA Western Region. \n\tThe amendment becomes effective November 6, 1970.