AD 78-06-01

78-06-01 TELEDYNE CONTINENTAL MOTORS: Amendment 39-3153 as amended by Amendment 39- 3193 is further amended by Amendment 39-3397. Applies to model TSIO-520-J and TSIO-520-N engines not previously fitted with improved elbow tube TCM P/N 642590, installed in, but not limited to, Cessna models 340A and 414. Also applies to Cessna model 340 as modified by STC's SA1881SW or SA186NW. Compliance is required as indicated except that the initial 25-hour inspection specified in paragraph A-2 is not required for Cessna aircraft manufactured after April 1, 1978. To prevent a separation of flexible elbow TCM P/N 635930 from the left hand (L.H.) No. 2 cylinder intake tube and possible engine malfunctions or stoppage, accomplish the following: A. 1. Within the next 12 months after the effective date of this amendment, replace induction system intake tube TCM P/N 629138 with new intake tube TCM P/N 642590. After the intake tube has been replaced with the new tube TCM P/N 642590, inspections required by paragraph A.2 do not apply. 2. Within the next 25 hours time in service after the effective date of this A.D., unless already accomplished, and thereafter at each 100 hours time in service, accomplish the following: (i) Inspect the L.H. elbow installation for full engagement over intake manifold tube and intercooler nipple beads with the hose clamps properly located behind nipple beads. (ii) Check torque of 30 to 35 inch pounds on left flexible intake manifold clamps (Cessna P/N U-84-270-SH) and intercooler clamps (Cessna P/N U-94-260-SH or B35A-21P). On aircraft which use TCM clamps (P/N 631972) at these joints, check for torque of 25 to 30 inch pounds. On Riley conversions which use Riley P/N 631972 clamps on these joints, check for 30 to 35 inch pounds. (iii) Upon request of the operator, an FAA maintenance inspector may adjust the repetitive inspection interval up to a maximum time between inspections of 125 hours to permit compliance at an established inspection period of the operator if the request contains substantiating data to justify the increase for that operator. 3. The inspections required by paragraph A-2 may be discontinued once the intake tube has been replaced with new tube TCM P/N 642590. B. Alternate methods of compliance may be acceptable if approved by the Chief, Engineering and Manufacturing Branch, Federal Aviation Administration, Southern Region, Atlanta, Georgia. C. Appropriate maintenance record must be made in accordance with FAR 43.9. Amendment 39-3153 became effective March 14, 1978. Amendment 39-3193 became effective immediately upon publication. This amendment 39-3397 becomes effective January 24, 1979.