The bulletin
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` SPECIAL AIRWORTHINESS INFORMATION BULLETIN SAIB: NM-12-20 SUBJ: Oxygen: Oxygen System Cylinder and Valve Assembly Date: March 13, 2012 This is information only. Recommendations aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin advises registered owners and operators of various transport category airplanes of the correct operation of Carleton Technologies Inc., oxygen system cylinder and valve assemblies having part numbers B42365-1 and B43570-1.
Background
Recent events indicate that certain operators and maintenance personnel may not understand the variable torque design of the shutoff valve installed on the subject oxygen cylinder because of the difference in resistance in opening and closing the valve assembly. This oxygen cylinder has a shutoff valve that personnel may presume is open when it is only partially open. Therefore, the effectiveness of the flightcrew (or other) oxygen systems during an emergency situation may be compromised.
Carleton Technologies, Inc. has issued Service Information Letter SIL-04577-35-006, dated May 21, 2010, to provide operators with guidelines for opening and closing the oxygen cylinder and valve assemblies. The guidance in the SIL does not change any procedures in the affected Component Maintenance Manual.
At this time, the airworthiness concern is not an unsafe condition that would warrant airworthiness directive (AD) action under Title 14 of the Code of Federal Aviation Regulations (14 CFR) part 39.
Recommendations
The FAA recommends that all owners and operators of transport category airplanes equipped with these assemblies comply with the guidelines outlined in Carleton Technologies Inc., Service Information Letter SIL-04577-35-006, dated May 21, 2010. We also recommend ensuring that maintenance crews are properly trained before servicing this equipment. Additionally, we recommend flight deck testing (“push-to-test”) of crew oxygen systems be conducted each time a flight deck oxygen cylinder is changed, according to approved maintenance procedures.
For Further Information Contact
Susan L. Monroe, Aerospace Engineer, Cabin Safety and Environmental Systems Branch, ANM-150S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue SW; Renton, Washington 98057-3356; phone: (425) 917-6457; fax: (425) 917-6590; email: susan.l.monroe@faa.gov.
For Related Service Information Contact
Carleton Technologies, Inc., 10 Cobham Drive, Orchard Park, New York, 14127;
phone: (716) 662-0006.