# AD 69-15-03: Muffler Assembly - Type: Airworthiness directive - Status: Current - Products: Lycoming O-320-A1A, A1B, A3A, A3B or Lycoming O-320-B1A, B1B… (D'Shannon Products STC SA135CE or 8 others) - Effective: August 20, 1969 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Small airplane - Amendment: 39-798 - Registered aircraft: 23,685 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/F1484C6E5D9F68CA86256A1C00749BB0.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/69-15-03 ## The airworthiness directive 69-15-03 CESSNA: Amendment 39-798. Applies to all Cessna Model 170, 172, and 175 series airplanes modified in accordance with Supplemental Type Certificates SA3-13, SA3-126, SA3-571, SA3-672, SA3-674, SA135CE, SA420CE, SA421CE, or SA424CE, incorporating a Piper Muffler Assembly, P/N 10308-00, with the installation of a Lycoming engine. Compliance required as indicated. To detect cracks in the muffler assembly, accomplish the following: (a) Inspect muffler assemblies with less than 950 hours' time in service on the effective date of this AD, in accordance with paragraph (c) below within the next 50 hours' time in service and thereafter at intervals not to exceed 100 hours' time in service from the last inspection until accumulating 950 hours' time in service, then comply with paragraph (b) below. (b) Inspect muffler assemblies with more than 950 hours' time in service on the effective date of this AD, in accordance with paragraph (c) below within the next 50 hours' time in service and thereafter at intervals not to exceed 50 hours' time in service from the last inspection. (c) Inspect the engine exhaust muffler and shroud assembly (including the internal baffle tube and tail pipe), carburetor heat shroud and air duct, support braces, clamps and brackets, exhaust stacks and manifolds. Remove muffler assembly, disconnect air ducts, stacks, and shrouds as necessary, and visually inspect exterior and interior surfaces with a probe light and mirror for signs of cracks, corrosion, burn-throughs, heat damage, collapsed stack, or weld separations. Special attention should be given to the exhaust stack under the carburetor heat shroud. Except for the initial inspection, the muffler assembly need not be removed from the airplane if the shroud is opened for inspection of external portions of the muffler and the internal portions are inspected through the muffler tail pipe outlet and one end of the muffler at the stack connection. CAUTION:Do not alter these mufflers to remove the internal baffle tube without prior FAA approval. (Piper Service Letter No. 324B describes the critical areas.) (d) Replace or repair parts having any of the defects listed in paragraph (c) before further flight, and thereafter comply with the inspection requirements of paragraph (a) or (b), whichever is applicable. Make welding repairs and pressure test in accordance with Advisory Circular AC 43.13-1 or an FAA approved equivalent. Care should be exercised when reinstalling the exhaust system components to prevent distortion or preloading of parts. This amendment becomes effective August 20, 1969. ## Affected data sheets (3) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS 3A12](https://openairdocs.org/tcds/3A12): Textron Aviation Inc.; names 18 of 18 models: 172F (USAF T-41A), 172M, 172Q, 172R, 172K, 172G, 172A, 172L… - [TCDS 3A17](https://openairdocs.org/tcds/3A17): Textron Aviation Inc.; names 5 of 12 models: 172RG, 175, 175B, 175C, 175A - [TCDS A-799](https://openairdocs.org/tcds/A-799): Textron Aviation Inc.; names 3 of 3 models: 170, 170A, 170B ## 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: 23,685 (23,685 by airframe model, 0 by engine model) - Makers: Cessna 22,446, Textron 1,239 Models with the most aircraft: - [Cessna 172M](https://openairdocs.org/model/cessna-172m): 3,573 aircraft (airframe model) - [Cessna 172N](https://openairdocs.org/model/cessna-172n): 3,138 aircraft (airframe model) - [Cessna 172S](https://openairdocs.org/model/cessna-172s): 1,915 aircraft (airframe model) - [Cessna 172](https://openairdocs.org/model/cessna-172): 1,805 aircraft (airframe model) - [Cessna 170B](https://openairdocs.org/model/cessna-170b): 1,300 aircraft (airframe model) - [Textron 172S](https://openairdocs.org/model/textron-172s): 1,239 aircraft (airframe model) - [Cessna 172P](https://openairdocs.org/model/cessna-172p): 1,111 aircraft (airframe model) - [Cessna 172K](https://openairdocs.org/model/cessna-172k): 1,026 aircraft (airframe model) - [Cessna 172L](https://openairdocs.org/model/cessna-172l): 857 aircraft (airframe model) - [Cessna 172H](https://openairdocs.org/model/cessna-172h): 780 aircraft (airframe model) - [Cessna 172G](https://openairdocs.org/model/cessna-172g): 722 aircraft (airframe model) - [Cessna 172F](https://openairdocs.org/model/cessna-172f): 717 aircraft (airframe model) - [Cessna 172R](https://openairdocs.org/model/cessna-172r): 683 aircraft (airframe model) - [Cessna 172E](https://openairdocs.org/model/cessna-172e): 617 aircraft (airframe model) - [Cessna 175](https://openairdocs.org/model/cessna-175): 536 aircraft (airframe model) - [Cessna 170A](https://openairdocs.org/model/cessna-170a): 513 aircraft (airframe model) - [Cessna 172D](https://openairdocs.org/model/cessna-172d): 471 aircraft (airframe model) - [Cessna 172RG](https://openairdocs.org/model/cessna-172rg): 445 aircraft (airframe model) - [Cessna 172A](https://openairdocs.org/model/cessna-172a): 435 aircraft (airframe model) - [Cessna 172B](https://openairdocs.org/model/cessna-172b): 413 aircraft (airframe model) All 29 models: https://openairdocs.org/ad/69-15-03/models.md Every aircraft: https://openairdocs.org/ad/69-15-03/aircraft.md ## Related documents - [AC 43.13-1B CHG 1 Ed Update](https://openairdocs.org/ac/43.13-1): Acceptable Methods, Techniques, and Practices—Aircraft Inspection and Repair. Cited as AC 43.13-1 in the AD's requirements - [STC SA135CE](https://openairdocs.org/stc/SA135CE): Installation of Lycoming O-320-A1A, A1B, A3A, A3B or Lycoming O-320-B1A, B1B, B3A, B3B engine, Hartzell HC-82X or HC-A2X series propellers with 7636D-4 blades and Woodward Model 210080 Governor. Data required: Doyn drawing 2000 dated February 21, 1063 and Doyn installation instructions dated February 21, 1963.. D'Shannon Products Ltd., Named in the applicability - [STC SA3-126](https://openairdocs.org/stc/SA3-126): Lycoming O-340-A1A engine and Hartzell HC-82XG-1DB/8433-12 propeller.. D'Shannon Products Ltd., Named in the applicability - [STC SA3-13](https://openairdocs.org/stc/SA3-13): Install 170 hp Lycoming O-340-A1A engine and Hartzell HC-82XL-1DB/8433-12 propeller according to Doyn data listed on Engineering Releases 100 (3/22/58), 1010 (3/16/57), 1011 (8/28/57), 1012 (7/15/57), 1014 (3/30/57), 1050 (7/13/57), 1051 (& DCN 1, 12/10/57), 1052 (7/19/57), 1053 (7/19/57), 1099 (3/22/58), and Instructions (2 sheets, undated) Data required for parts manufacture: As listed on Engineering Releases 1001 (1/18/57), 1002 (12/21/57), 1003 (5/1/57), 1004 (7/13/57), 1005 (7/12/57), 1006 (3/30/57), 1007 (4/12/57), 1008 (2/27/57), 1009 (10/23/57), 1015 (2/25/56).. D'Shannon Products Ltd., Named in the applicability - [STC SA3-571](https://openairdocs.org/stc/SA3-571): Lycoming O-360-A1D engine, McCauley 2D36C14/78KM-4 or Hartzell HC-C2YK-1A/7666-2 propellers.. D'Shannon Products Ltd., Named in the applicability - [STC SA3-672](https://openairdocs.org/stc/SA3-672): Installation of Lycoming O-360-A1A, A1D, or B1B engine with McCauley 2D36C14-X/78KM-4 propeller or Lycoming O-360-A1A and A1D engines with Hartzell HC-C2YK-1A/7666A-2 propeller. Data required: Doyn Aircraft, Inc. Drawings: 1000, 1005 Rev. C, 1006 Rev. C, 1009, 1010 Rev. A, 1011, 1012 Rev. A, 1013, 1014, 1015, 1016, 1099, 1100 Rev. B, 1101 Rev. A, 1102, 1103 Rev. A, 1104, 1107, 1150. Drawing Changes Notices: 1005-5A, 1006-8A, 1006-6, 1009-2A, 1199-1A, 1199-2A, and 1199-3A.. D'Shannon Products Ltd., Named in the applicability - [STC SA3-674](https://openairdocs.org/stc/SA3-674): Installation of Lycoming O-360-A1D engine and McCauley 2D36C14/78KM-4 or Hartzell HC-C2YK-1A/7666-2 propeller in accordance with Doyn Aircraft Drawing List for Model 1700 conversion dated May 6, 1964; for Cessna Model 175B: Atlas Aviation Oil Cooler Installation dated September 12, 1967, is required.. D'Shannon Products Ltd., Named in the applicability - [STC SA420CE](https://openairdocs.org/stc/SA420CE): Installation of 0-360-( ) series engines, fixed pitch and constant speed propellers. Barbara or Bob Williams, Named in the applicability - [STC SA421CE](https://openairdocs.org/stc/SA421CE): Installation of a Lycoming O-360-A1A or O-360-A1D 180 hp engine or O-360-B1B 168 hp engine and constant speed propeller. Williams Barbara or Bob, Named in the applicability - [STC SA424CE](https://openairdocs.org/stc/SA424CE): Installation of Lycoming 0-360- ( ) engine and Hartzell HC-C2YK-1N7666-2, HC-92ZK-8D/8447-12A or McCauley 2D36Cl4/7BKM-4 propeller or McCauley or Sensenich fixed pitched propeller. *Landplane only. Barbara or Bob Williams, Named in the applicability --- 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.