77-14-13 HAWKER SIDDELEY AVIATION, LTD: Amendment 39-2958. Applies to Model BH-125 Series 600A airplanes, S/N's 25/6001-6004, 6007, 6009-6011, 6013, 6014, 6016, 6018, 6020, 6022-6026, 6032, 6034, 6038, 6040, 6044, 6046, certificated in all categories.
Compliance is required within the next 300 hours time in service after the effective date of this AD, unless already accomplished.
To prevent possible unwanted rolling of the airplane when operating at buffet onset, add vortex generators to the leading edge of each wing by incorporating Hawker Siddeley Aviation, Ltd., Modification No. 252442 in accordance with Section 2 entitled "Accomplishment Instructions" of Hawker Siddeley Aviation, Ltd., Service Bulletin 57-48-(2442), dated June 25, 1975, including Revision 1, dated July 23, 1975, or an FAA-approved equivalent.
This amendment becomes effective August 8, 1977.