Office ofthe Chairman



### Docket Management Facility U.S. Department ofTransportation 1200NewJerseyAvenue, SE 

## National Transportation Safety Board Washington, D.C. 20594



## SEP 

## 2 52009

West BuildingGround Floor, Room W12-140 Washington, D.C. 20590-0001

Re: DocketNo. FAA-2008-0052; Directorate Identifier 2008-NE-0l-AD

DearSiror Madam:

The National Transportation Safety Board (NTSB) has reviewed the Federal Aviation Administration (FAA) notice of proposed rulemaking (NPRM), "Airworthiness Directives; Engine Components, Inc, (ECi) Reciprocating Engine Cylinder Assemblies" published at 74 

### Federal Register 37955 on July 30, 2009. The proposed rule would supersede an existing airworthiness directive (AD) for certain Engine Components, Inc. (ECi), "Titan" series cylinder assemblies, part number (PIN) AEL65102, installed on Lycoming Engines (formerly Textron Lycoming), models 320, 360, and 540 series, "ParallelValve" reciprocating engines.

This NPRM proposes to amend 14 

### Code o.f'Federal Regulations Part 39 by superseding AD 2008-19-05, Amendment 39--15672 (73 FR 53105, September 15, 2008). AD 2008-19-05, "Engine Components, Inc. (ECi) Reciprocating Engine Cylinder Assemblies," requires the following: initial and repetitive visual inspections and compression tests to detect cracks that initiated in the cylinder head at the head-to-barrel interface and propagated through the cylinder head; replacement ofcylinder assemblies found with cracked heads; and replacement ofcertain cylinderassemblies atnew reduced times-in service. The newAD will extend the serial numbers ofcylinderassemblies affected by theprevious AD.

AD 2008-19-05 was issued on Yiay 13, 2008, as a result ofreports of45 ECi cylinder failures involving head separations. Such a failure reduces engine power and could cause the engine to lose as much as 80 percent ofits power or fail entirely, resulting in a loss ofaircraft control. Following the issuance ofAD 2008-19-05, the FAA received reports of 10 additional head separation failures ofECi cylinder assemblies involving cylinder serial numbers not listed in the AD, and the NTSB received oneofthe 10 cylinders for examination. To date, a total of55 head separations ofECi cylinder assemblies have occurred, resulting in engine shutdowns and emergency landingsinboth airplanes and helicopters.

The NTSB began detailed investigations of fatigue failures in ECi cylinders in 2001 when a Cessna 414, registered as N414NG, experienced a significant loss ofpower in the left engine resulting in a crash, a postimpact fire, and three fatalities. The left engine was a Lycoming model 10-720-BIBD that had been overhauled 270 operating hours before the2

accident. The overhaul included installation ofcylinders overhauled by ECi. Between 2001 and 2005, the NTSB examined numerous cylinders thathad failed in a similarmannerbut wasunable to discern a pattern due to the complexity ofthe manufacturing and overhauling processes, the non-reporting offailed cylinders, and inaccurate reporting found in the FAA's Service Difficulty Report (SDR) system. Operators and maintenance personnel associated with the failed cylinders reported to NTSB field investigators that they did not use the SDR system as it was too complicated, took too much time, and was hard to use. Comparisons ofSDR data with failed cylinders revealed that, in some cases, the failed cylinder was identified as a Lycoming cylinder when it was actually an ECi cylinderthat had beenremoved from a Lycomingengine.

In 2005, a cylinder task force comprising two NTSB and two FAA representatives was formed to study the fatigue failure ofcylinders, which now included both domestic and foreign failures. The task force visited cylindermanufacturers, machining facilities, a castinghouse, and
a prominent overhaul facility. The FAA Aircraft Certification Office (ACO) in Fort Worth, which has oversight responsibility for ECi, was continually apprised ofthe task force's progress and supplied with copies ofall examination reports. The Fort Worth ACO eventually produced the existing AD. The 10 additional cylinder head separations of ECi cylinders with serial numbers outside ofthe AD prompted ajointmeeting ofECi, the ACO, and members ofthe task force at ECi on May 12, 2009. The amendment proposed in this NPRM to extend the serial numbers ofaffected cylinders is aresultofthat meeting. The meeting also discussed in detail the cylindertestingprogram initiated by ECi after a previous meeting with the cylindertask force in October2006. The testing program included ECi and othermanufacturer's cylinders and had by May 2009 revealed that one particular dimensional changeproduced a significant increase in the operating life ofa cylinder. ECi reported that modified cylinders had yet to fail in bench testing and that testing would continueto determine a finite life.

Because the actions proposed in the NPRM are consistent with the information gathered during NTSB accident investigations and by the task force, the NTSB supports adoption ofthe proposed AD. In addition, the NTSB understands that the FAA is monitoring manufacturer's efforts to improve the design ofcylinder assemblies to minimize head separations. The NTSB strongly supports timely release oftheseimprovements.

The NTSB appreciatestheopportunityto comment onthis proposedrule.

DeborahA.P. Hersman Chairman