# AD 76-13-09: Left Hand Rear Exhaust Elbow, And Left And Right Hand Flanges - Type: Airworthiness directive - Status: Current - Products: Continental Motors TSIO-520-L - Effective: August 26, 1976 - Superseded by: Nothing supersedes this AD - Product type: Engine - Amendment: 39-2691 - Registered aircraft: 4,114 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/E285A3D5AFB80F3A86256E1200477430.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/76-13-09 ## The airworthiness directive 76-13-09 TELEDYNE CONTINENTAL MOTORS: Amendment 39-2655 as amended by Amendment 39- 2691. Applies to Teledyne Continental Motors Model TSIO-520-L, serial numbers 508000 through 508164, and serial numbers 508166 through 508261. Compliance required within the next ten hours time in service after the effective date of this AD, unless already accomplished. Inspections covered in steps 1, 2, 3 and 4 below must be repeated each 25 hours time in service from the initial inspection until replaced by a new elbow TCM Part Number 642067 and new exhaust flange TCM Part Number 642066. To detect cracks in the left hand rear exhaust elbow, P/N 640708, and the left and right hand flanges on the exhaust to turbo adapter, P/N 640712, and to provide sufficient end clearance between the connector tube assembly, P/N 640711, and the connector tube, P/N 640710, inspect, repair or replace, as required, in accordance with the following procedure: 1. Remove couplings, P/N 641284, from each side of the adapter. 2. Remove the left hand elbow, (2-4-6 side), P/N 640708, and carefully inspect in the area of the weld closest to the flange, and the flange fillet radius (see illustration for cracks). 3. Check elbow (2-4-6 side), P/N 640708, for distortion in the area shown below (see illustration). 4. If any cracks are evident and/or distortion is readily discernible, replace the elbow (2-4-6), P/N 640708. (Replace with new elbow 642067 and flange 642066 when parts become available.) 5. Slip the connector, P/N 640711, to the right on the elbow (1-3-5 side), P/N 640710, until it bottoms out. With the flanges aligned, the gap between the flange on the turbo adapter (P/N 640712) and the flange on the connector (P/N 640711) must exceed .250 inches but not exceed .500 inches all the way around as shown in illustration. If this gap is less than .250 inches, remove sufficient material from the end of the elbow (1-3-5 side), P/N 640710, to provide .250 to .380 inch gap. If thegap exceeds .500 inches, replace the elbow (1-3-5 side), P/N 640710, with one meeting this inspection requirement. 6. Remove the turbo adapter, P/N 640712, from the engine. Carefully inspect the turbo adapter, P/N 640712, for cracks in the flange fillet radii (see illustration). If cracks are observed, replace. 7. Using suitable micrometers or dial indicator calipers, inspect the turbo adapter, P/N 640712, wall thickness in the machined area adjacent to the flange fillet radius on the entire circumference. The minimum allowable thickness is .075 inches (see illustration). If the wall thickness is less than .075 inches in any local area, replace the turbo adapter, P/N 640712, with one meeting this inspection requirement. 8. Reinstall couplings, P/N 641284. Insure flanges are symmetrically aligned. Tighten couplings to approximately 42 in. lbs. torque. Tap outer periphery of band to distribute tension, then tighten to 50 to 60 in. lbs. of torque. TCM Service Bulletin M76-14 covers this subject. Amendment 39-2655 became effective July 15, 1976. This amendment 39-2691 becomes effective August 26, 1976. ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS E8CE](https://openairdocs.org/tcds/E8CE): Continental Aerospace Technologies, Inc.; names 1 of 31 models: TSIO-520-L ## Registered aircraft it may apply to (OpenAirDocs) Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment. - Aircraft: 4,114 (0 by airframe model, 4,114 by engine model) - Makers: Cessna 3,180, Beech 672, Piper 173, Raytheon 61, Mooney 11, Meyers Industries 2, Navion 2, Ryan 2, Aero Commander 1, Cirrus Design 1 Models with the most aircraft: - [Continental TSIO-520 series](https://openairdocs.org/engine/continental-tsio-520-series): 4,064 aircraft (engine model) - [TCM Cont TSIO-520 series](https://openairdocs.org/engine/tcm-cont-tsio-520-series): 49 aircraft (engine model) - [Continental TSIO-520-L](https://openairdocs.org/engine/continental-tsio-520-l): 1 aircraft (engine model) All 3 models: https://openairdocs.org/ad/76-13-09/models.md Every aircraft: https://openairdocs.org/ad/76-13-09/aircraft.md Its text cites no advisory circulars or STCs. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.