AL 2005-08
17 October 2005
Engine Oil Filter Converter Plate Gasket
An ongoing investigation into a fatal crash of a Piper PA31-350 revealed that the in-flight fire was caused by the installation of an inappropriate engine oil filter converter plate gasket, part number (P/N) LW-13388.
Based on the fire pattern and damage to the fuselage, it was apparent that the oil filter converter plate gasket had failed, allowing pressurized engine oil to spray into the engine compartment. The engine oil ignited likely on contact with hot turbo-charger/exhaust components. The engine-driven fuel pump was subjected to considerable heat from the initial oil-fed fire and that, at some point, the pump casing melted.
Engine oil filter converter plate gaskets were originally identified by P/N LW-13388; these gaskets would be replaced at engine overhaul or "on- condition". However, in late 1999, a bad batch of gaskets got into the aviation supply system. These gaskets were manufactured from a different material and were found to break down over time, allowing loss of engine oil. The problem was identified and first addressed by Lycoming Mandatory Service Bulletin 543A, issued on 24 July 2000. A new gasket, P/N 06B23072, was subsequently manufactured to replace the old P/N LW-13388 gasket. The new gasket met all Textron Lycoming blueprint and test requirements and was installed on engines shipped from the factory after 4 October 2000.
On 3 July 2002, the Federal Aviation Administration (FAA) issued Airworthiness Directive (AD) 2002-12-07, which required in part, that before 1 October 2003 owners/operators of all affected engines replace the oil filter converter plate gasket with the newly manufactured part. The intent of this directive was to ensure that as of 1 October 2003, all affected engines would be equipped with the new gasket, P/N 06B23072, and that the inappropriate gasket, P/N LW 13388, would have been purged from the system.
The accident investigators contacted the engine overhaul facilities who indicated that inappropriate converter plate gaskets, identified by part number LW- 13388, are still being found in engines after the AD 2002-12-07 compliance deadline of 1 October 2003. The investigation also found that required vibro-peening of the exterior of the converter plates was not always being accomplished. Without the addition of this required marking, it is not possible to visually confirm compliance with the AD.
Transport Canada therefore emphasizes that all owners, operators and overhaul facilities shall ensure those affected engines must comply with all the requirements stated within the Airworthiness Directive 2002-12-07 and to ensure that all stocks of converter plate gaskets, P/N LW-13388 be discarded.
Any further defects or occurrences should be reported to Transport Canada, Continuing Airworthiness, Ottawa, via the service difficulty reporting program.
For further information contact a Transport Canada Centre, or call Mr. Marcel Gauthier, Continuing Airworthiness, Ottawa, telephone 613 952-4364, facsimile 613 996-9178 or e-mail gauthmr@tc.gc.ca.
For Director, National Aircraft Certification
B. Goyaniuk
Chief, Continuing Airworthiness
Note: For the electronic version of this document, please consult the following Web address:https://tc.canada.ca/en/aviation/aircraft-airworthiness/aircraft-certification