73-21-01\tMOONEY: Amdt. 39-1729. Applies to Mooney Models M20, M20A, M20B, M20C, M20D, M20E, M20F and M20G airplanes. \n\tCompliance required as indicated. \n\tTo prevent corrosion and/or misrigging in the flight control and landing gear systems which may result in binding or seizure of the joints and loss of flight control or collapse of the landing gear, accomplish the following: \n\t(a)\tWithin 25 hours time in service after July 10, 1972, unless already accomplished within the last 25 hours time in service, and thereafter at intervals not to exceed 12 calendar months from the last inspection or 100 hours time in service from the last inspection, whichever comes first, lubricate all flight control systems and landing gear system rod end bearings with a silicone spray lubricant or with an FAA approved equivalent lubricant. \n\t(b)\tWithin the next 50 hours time in service after July 10, 1972, unless already accomplished, install retracting links, P/N 530003-13 (1 ea.) and 510011-13 (2 ea.) on all M20B, C, E, F, and G aircraft and on M20D models converted to a retractable gear, or equivalent parts approved by the Chief, Engineering and Manufacturing Branch, Flight Standards Division, Southwest Region, FAA, Fort Worth, Texas. The new links incorporate grease fittings and improved overcenter travel resulting in lower preload rigging. New links are not required if the existing installations use -13 links which have grease fittings. (Reference Mooney Service Bulletin M20-155 dated 6-15-67, or later FAA approved revision.) \n\n\nAD 73-21-01 \n\n\tNOTE: For M20 and M20A models the present retract links are to be modified by the addition of grease fittings as shown in figures 1 and 2 attached. Follow procedures in Mooney M20/M20A Service and Maintenance Manual or other FAA approved procedure, for removal and replacement of links. Service Bulletins, Service Letters and Service Instructions referenced in this AD may be obtained from Mooney Aircraft, Louis Schreiner Field, Kerrville, Texas. \n\t(c)\tAt the next lubrication as required in (a) and thereafter at the same interval as specified in (a), perform a landing gear retraction test and check the landing gear rigging. Information regarding rigging and torque preload may be found in Mooney Service Bulletin No. M20-35A dated 7-11-60 for Models M20 and M20A, Mooney Service Instruction No. M20-32 dated 11-3-72 for other models or later FAA approved revisions. Special tools supplied by Mooney Aircraft as noted in the reference documents or FAA approved equivalent tools are required for proper preload rigging. \n\tThis supersedes Amendment 39-1455 (37 F.R. 11462), AD 72-12-02 as amended by Amendment 39-1482 (37 F.R. 13336). \n\tThis amendment becomes effective October 10, 1973.