# SAIB NE-14-13: Reciprocating Engine - Cylinder Mounting Studs - Type: Special airworthiness information bulletin (advisory, not mandatory) - Status: Current - Revision: 0 - Issued: March 24, 2014 - Products: Lycoming Engines AEIO-320-D1B, AEIO-320-D2B, AEIO-320-E1A, AEIO-320-E1B, AEIO-320-E2A, AEIO-320-E2B, AEIO-360-A1A, AEIO-360-A1B, AEIO-360-A1B6, AEIO-360-A1C, AEIO-360-A1D, AEIO-360-A1E and 624 more - Product type: Engine - PDF: https://openairdocs.org/files/sha256/48/64/486462fc8db957315b63c060f7a09c88730a1f35ee1cd9bd6be2cb57a8023b55 - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/8C01A9AAE28B401F86257CA50066C517.0001 - DRS record last changed: March 24, 2014 - Page: https://openairdocs.org/saib/NE-14-13 ## Text FAA Aviation Safety **SPECIAL AIRWORTHINESS** INFORMATION BULLETIN SUBJ: Reciprocating Engine - Cylinder Mounting Studs SAIB: NE-14-13 Date: March 24, 2014 This is information only. Recommendations aren’t mandatory. Introduction This Special Airworthiness Information Bulletin (SAIB) alerts you, owners, operators, and certificated repair facilities of Lycoming Engines of the possible failure of engine thru-studs, and/or cylinder mounting studs. The airworthiness concern is not an unsafe condition that would warrant airworthiness directive action under Title 14 of the Code of Federal Regulations (14 CFR) part 39. Background The Federal Aviation Administration received reports from an aviation authority of another country identifying cylinder mounting studs that failed on Lycoming engines due to the absence of protective cadmium plating on the studs. One report concerned a No. 2 cylinder that had separated from the crankcase after failure of the mounting studs. This resulted in damage to the surrounding crankcase and a failed connecting rod. Of the eight studs that secured the cylinder to the crankcase prior to failure, four were lost with the released sections of the crankcase and cylinder. Laboratory analysis determined that one of the four remaining studs had a high cycle fatigue fracture. The fracture started from a single point corresponding to a corrosion pit in a thread root. Evidence of cadmium plating remained on the coarse threaded section of the stud, but there was no evidence of the cadmium plating where the corrosion pit developed. A report of a routine maintenance check of another aircraft, from the same operator’s fleet, stated that one failed cylinder mounting stud was found. Analysis of this failed stud confirmed that it had also failed in high cycle fatigue initiating from a corrosion pit in the thread root. Cadmium plating was not found on the section of the stud inspected, although traces of cadmium plating were present on the ‘hold down’ nut. The safety recommendation made by the aviation authority of the other country and considered for implementation by the FAA is: “It is recommended that Lycoming introduce additional maintenance requirements to ensure that the cadmium plating on the cylinder mounting studs, fitted to Lycoming engines, is not permitted to degrade to a level where corrosion of the base stud material can result in failure of the stud.” When contacted by the New York Aircraft Certification Office (NYACO) Lycoming maintained that the instructions in the Lycoming Overhaul Manual are adequate. Lycoming also advised that the potential causes of stud failure include: - Improper torque at cylinder installation - Corrosion pitting - Improper torque due to excessive paint on the cylinder flange (all Lycoming cylinders are painted, the problem is caused by excessive paint on the cylinder flange mounting surface to the crankcase and/or the hold down nut area, prior to installation) - Fretting on the crankcase main bearing mating surfaces. The NYACO also reviewed the National Transportation Safety Board’s (NTSB) database for cylinder stud failures occurring between January 2000 and June 2013 and found 7 failures on Lycoming engines, and 2 failures on Continental engines. The Board attributed the failures to fatigue of the studs that was caused predominately by insufficient preload and/or improper installation. Corrosion pitting was not mentioned as a cause of failure by the Board. One of the Board’s reports stated that three of the cylinder studs for the No. 3 cylinder separated due to fatigue. In addition, the fatigue separation of multiple cylinder studs resulted in looseness of the cylinder, and the subsequent vibration and fatigue of a fuel injector line. There was no reported fire in this event. Eleven U.S. engine shops were asked about their experience with cylinder studs and the Lycoming overhaul manual. They all agreed that the instructions in the Lycoming overhaul manual are adequate. Some engine shops reported seeing some stud failures, but they did not indicate that corrosion pitting was a problem. Recommendations 1. Inspect cylinder studs and thru-studs, for corrosion pits and missing cadmium plating. 2. Follow the cylinder installation instructions in the Lycoming overhaul manual or Lycoming Service Instruction No. 1029D. 3. Use Lycoming special tools, or their equivalent, to torque the cylinder nuts. 4. When using the special wrenches to torque cylinder nuts, ensure the wrenches do not contact the cylinder or other parts of the engine. Wrench contact can result in a correct torque indicated by the torque wrench, but the actual torque applied to the nut, and the clamping force, will be lower than required. 5. When accessible, inspect the crankcase main bearing mating surfaces for fretting. Lycoming has advised that no fretting is allowed. For Further Information Contact Norm Perenson, Aerospace Engineer, New York Aircraft Certification Office, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (516) 228-7337; fax: (516) 794-5531; email: norman.perenson@faa.gov. ## Registered aircraft it may concern (OpenAirDocs) Registry models matched by make and model, the same way as ADs, most registered aircraft first. - [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series): 27,057 registered aircraft (engine model) - [Lycoming O&VO-360 series](https://openairdocs.org/engine/lycoming-o-vo-360-series): 11,931 registered aircraft (engine model) - [Lycoming I0360 series](https://openairdocs.org/engine/lycoming-i0360-series): 6,174 registered aircraft (engine model) - [Lycoming 0-235 series](https://openairdocs.org/engine/lycoming-0-235-series): 6,133 registered aircraft (engine model) - [Lycoming 0-540 series](https://openairdocs.org/engine/lycoming-0-540-series): 5,228 registered aircraft (engine model) - [Lycoming TI0-540 series](https://openairdocs.org/engine/lycoming-ti0-540-series): 4,886 registered aircraft (engine model) - [Lycoming IO-540 series](https://openairdocs.org/engine/lycoming-io-540-series): 4,219 registered aircraft (engine model) - [Lycoming IO-360-L2A](https://openairdocs.org/engine/lycoming-io-360-l2a): 2,644 registered aircraft (engine model) - [Lycoming IO-320 series](https://openairdocs.org/engine/lycoming-io-320-series): 1,707 registered aircraft (engine model) - [Lycoming IO-540-AE1A5](https://openairdocs.org/engine/lycoming-io-540-ae1a5): 1,040 registered aircraft (engine model) - [Lycoming O-360 series](https://openairdocs.org/engine/lycoming-o-360-series): 1,023 registered aircraft (engine model) - [Lycoming IO-360-B4A](https://openairdocs.org/engine/lycoming-io-360-b4a): 985 registered aircraft (engine model) - [Lycoming 0-360-A1D](https://openairdocs.org/engine/lycoming-0-360-a1d): 968 registered aircraft (engine model) - [Lycoming AEIO-360 series](https://openairdocs.org/engine/lycoming-aeio-360-series): 884 registered aircraft (engine model) - [Lycoming IO-360-A1B6D](https://openairdocs.org/engine/lycoming-io-360-a1b6d): 844 registered aircraft (engine model) - [Lycoming IO-540-AB1A5](https://openairdocs.org/engine/lycoming-io-540-ab1a5): 773 registered aircraft (engine model) - [Lycoming TIO-540-AJ1A](https://openairdocs.org/engine/lycoming-tio-540-aj1a): 720 registered aircraft (engine model) - [Lycoming O-360-A1A](https://openairdocs.org/engine/lycoming-o-360-a1a): 601 registered aircraft (engine model) - [Lycoming TIO-540-AK1A](https://openairdocs.org/engine/lycoming-tio-540-ak1a): 508 registered aircraft (engine model) - [Lycoming TIO-540-AE2A](https://openairdocs.org/engine/lycoming-tio-540-ae2a): 488 registered aircraft (engine model) - [Lycoming AEIO-540 series](https://openairdocs.org/engine/lycoming-aeio-540-series): 433 registered aircraft (engine model) - [Lycoming O-360-A4M](https://openairdocs.org/engine/lycoming-o-360-a4m): 418 registered aircraft (engine model) - [Lycoming HIO-360 series](https://openairdocs.org/engine/lycoming-hio-360-series): 336 registered aircraft (engine model) - [Lycoming IO-390 series](https://openairdocs.org/engine/lycoming-io-390-series): 312 registered aircraft (engine model) - [Lycoming O-360-A1P](https://openairdocs.org/engine/lycoming-o-360-a1p): 302 registered aircraft (engine model) - [Lycoming O-540-F1B5](https://openairdocs.org/engine/lycoming-o-540-f1b5): 299 registered aircraft (engine model) - [Lycoming TI0-541 series](https://openairdocs.org/engine/lycoming-ti0-541-series): 271 registered aircraft (engine model) - [Lycoming O-320-E2D](https://openairdocs.org/engine/lycoming-o-320-e2d): 258 registered aircraft (engine model) - [Lycoming O-320 series](https://openairdocs.org/engine/lycoming-o-320-series): 256 registered aircraft (engine model) - [Lycoming O-360-J2A](https://openairdocs.org/engine/lycoming-o-360-j2a): 255 registered aircraft (engine model) - [Lycoming AEIO-580-B1A](https://openairdocs.org/engine/lycoming-aeio-580-b1a): 253 registered aircraft (engine model) - [Lycoming GO-480 series](https://openairdocs.org/engine/lycoming-go-480-series): 246 registered aircraft (engine model) - [Lycoming IO-540-D4A5](https://openairdocs.org/engine/lycoming-io-540-d4a5): 237 registered aircraft (engine model) - [Lycoming IO-360 series](https://openairdocs.org/engine/lycoming-io-360-series): 217 registered aircraft (engine model) - [Lycoming IO-360-A1A](https://openairdocs.org/engine/lycoming-io-360-a1a): 196 registered aircraft (engine model) - [Lycoming IO-360-A1D6](https://openairdocs.org/engine/lycoming-io-360-a1d6): 192 registered aircraft (engine model) - [Lycoming TIO-540 series](https://openairdocs.org/engine/lycoming-tio-540-series): 191 registered aircraft (engine model) - [Lycoming VO-435 series](https://openairdocs.org/engine/lycoming-vo-435-series): 191 registered aircraft (engine model) - [Lycoming IO-360-M1B](https://openairdocs.org/engine/lycoming-io-360-m1b): 185 registered aircraft (engine model) - [Lycoming O-320-A2B](https://openairdocs.org/engine/lycoming-o-320-a2b): 180 registered aircraft (engine model) - [Lycoming IO-540-C4B5](https://openairdocs.org/engine/lycoming-io-540-c4b5): 179 registered aircraft (engine model) - [Lycoming IO-360-B1G6](https://openairdocs.org/engine/lycoming-io-360-b1g6): 177 registered aircraft (engine model) - [Lycoming I0-360-B1E](https://openairdocs.org/engine/lycoming-i0-360-b1e): 141 registered aircraft (engine model) - [Lycoming IO-360-A1B6](https://openairdocs.org/engine/lycoming-io-360-a1b6): 141 registered aircraft (engine model) - [Lycoming O-360-C1G](https://openairdocs.org/engine/lycoming-o-360-c1g): 141 registered aircraft (engine model) - [Lycoming O-320-D3G](https://openairdocs.org/engine/lycoming-o-320-d3g): 134 registered aircraft (engine model) - [Lycoming AEIO-360-H1B](https://openairdocs.org/engine/lycoming-aeio-360-h1b): 124 registered aircraft (engine model) - [Lycoming O-320-D1A](https://openairdocs.org/engine/lycoming-o-320-d1a): 116 registered aircraft (engine model) - [Lycoming IO-360-M1A](https://openairdocs.org/engine/lycoming-io-360-m1a): 113 registered aircraft (engine model) - [Lycoming VO-540 series](https://openairdocs.org/engine/lycoming-vo-540-series): 110 registered aircraft (engine model) All 670: https://openairdocs.org/saib/NE-14-13/models.md --- 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.