69-11-03\tBOEING: Amdt. 39-766 applies to Model 707-300B and 707-300C series airplanes listed as follows. AA Serial No. 20170, PA Serial Nos. 20030, 20031, 20033, and 20034, LU Serial No. 20123, OA Serial No. 20035, TP Serial No. 19969, LY Serial No. 20097, PK Serial No. 19866, NW, RD, PK and EJ airplane serial numbers on which rudder power control units purchased as spares from Bertea have been installed. \n\tCompliance required as indicated unless already accomplished. \n\tTo prevent cracking of the control rod end of the rudder power control unit, accomplish the following: \n\tPrior to next flight, remove any rudder power unit, Boeing Part Number 10-60815, having Bertea Serial Number 760 through 818 and replace with a power unit of the same part number but of a different serial number than noted above. Power units Numbers 760 through 818 may be returned to service when the rod end, Bertea Part Number 60043-9 (Schafer Part Number YTD 112A), has been replaced in accordance with FAA approved instructions from the manufacturer (Bertea). The airplane may not be ferried under the provisions of FAR 21.197(b) and (c). Airplanes may be ferried after issuance of individual special flight permits under the provisions of FAR 21.197(a)(1) and FAR 21.199 after a pre-takeoff determination that the rudder operates normally in the "Boost On" mode. Pursuant to FAR 21.199(a)(6), the limitations in the special flight permit will prohibit flights over congested areas or which may otherwise endanger persons or property on the ground. \n\tThis amendment becomes effective upon publication in the FEDERAL REGISTER for all persons except those to whom it was made effective immediately by telegram dated April 14, 1969.