Control Cable Terminal - Retirement 1. Applicability All aircraft flight control cable terminal fittings over 15 years old made from stainless steel specification SAE-AISI 303Se, including, but not limited to, standard terminal part numbers AN669 and MS21260. 2. Purpose The objective of this bulletin is to urge operators and maintainers to consider replacing all controlcables having terminal fittings manufactured from stainless steel SAE-AISI 303Se before reaching 15 years time in service. 3. Background Reports of flight control cable terminal fitting separationfailures continue to be received in Australia and the United States. Failure of a flight control cable can result in loss of control. Investigations have revealed that the failed terminals had been inservice for approximately 15 years or more, were manufactured from SAE-AISI 303Se stainless steel and identified by standard terminal fitting part numbers AN669 and MS21260. It should be noted that theseterminal fittings have been incorporated into flight control cable assemblies which are then identified by different manufacturers part numbers in the aircraft Illustrated Parts Catalogue (IPC).Terminal fitting separation as described in this Airworthiness Bulletin is due to chloride stress-corrosion cracking, a form of intergranular cracking which can originate from within the terminal.Therefore, even very small corrosion pits on the surface of the terminal fitting are indications that the terminal maybe very close to failure. AWB Date : 27-001 Issue : 31 October 2011 2
Figure 1 -Separation at threaded end of terminal
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Control Cable Terminal - Retirement AWB Date : 27-001 Issue : 31 October 2011 2
Figure 2 - Separation at swaged end ofterminal
Figures 1 and 2 show how separation failures have occurred at the shaft on the threaded end and at the swaged section of the terminal. An inspection for pitting on the terminal surface is...