COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Oxygen Systems
AD/OXY/3
Amdt 1
Puritan-Bennett Oxygen Regulator NK Diaphragm - Replacement
Applicability: Puritan-Bennett Aero Systems Company oxygen masks as follows : P/N 174039 S/N 0001-0012, P/N 174010-01 and 174010-03 S/N 00100-00144, 00146, 00147,
00149-00259, 00261-00273, 00275-00292, 00294-00390 and P/N ZMR 100 series
S/N 6603-7234.
Requirement: 1. Remove diaphragm assembly P/N F334-1001-1 and install diaphragm assembly P/N F334-1001-1 modified to include diaphragm and plate assembly P/N F334- 1003-1 Revision E.
2. After modification per para. 1, permanently mark letter "M" at the end of or beneath the mask serial number. This serial number is located under the face cushion on the left-hand side of the hardshell on the 174039 and ZMR 100 series masks, and on the back surface of the head harness on the 174010-01 and 174010- 03 masks.
3. The modified diaphragm replacement (para. 1) shall be accomplished by returning the mask to Puritan-Bennett Aero Systems Company, 111 Penn Street, El Segundo, California 90245, USA. However this replacement in ZMR 100 series masks listed below may be accomplished in the field in accordance with the following Puritan-Bennett Aero Systems ATA Component Maintenance Manuals:
35-10-25 for the ZMR 160 mask. 35-10-27 for the ZMR 129 mask. 35-10-28 for the ZMR 129-1 mask. 35-10-29 for the ZMR 118 mask.
Note 1. Puritan-Bennett Aero Systems Company Service Bulletin No. 1 pertains to this subject.
Note 2. FAA AD 81-08-04 Amendment 39-4092 refers.
Compliance: Within 100 hours time in service after 30 June 1981.
Note: Oxygen masks which have previously been reworked in accordance with AD/OXY/3 are deemed to comply with this Directive AD/OXY/3A.
Background: The regulators in approximately half of the mask assemblies listed contain oversize diaphragms. Under certain conditions, an oversize diaphragm can cause a regulator inlet valve either to leak or to develop positive pressure within the face cone.
Although the regulator may work properly in normal usage, it can develop one of the above conditions without warning. There is no reliable field test method for determining when or whether the mask will develop a problem. This Directive is revised in issue to conform with revisions to FAA AD 81-02-03 which include additional S/Nos. of masks and a method of field compliance.
Overview
The Civil Aviation Regulations 1998, as amended by AD/OXY/3A, addresses issues related to the safety of oxygen systems in civil aviation, specifically targeting the Puritan-Bennett oxygen regulators used in various aircraft oxygen masks. This amendment was introduced to mitigate risks associated with oversize diaphragms in the regulators, which could lead to leaks or the development of positive pressure within the face cone under certain conditions. This legislative instrument was enacted by the Civil Aviation Safety Authority, aiming to ensure the ongoing airworthiness and safety of aircraft by enforcing timely modifications to the affected oxygen masks. The policy objective is to prevent potential hazards that could compromise the safety of passengers and crew by ensuring that the oxygen systems function reliably without warning signs of failure.
Scope and Application
The Civil Aviation Regulations 1998, under Part 39 - 107, specifically address the Airworthiness Directives for oxygen systems, particularly focusing on the NK diaphragm replacement for certain Puritan-Bennett oxygen masks. This applies to specific models and serial numbers of the masks manufactured by Puritan-Bennett Aero Systems Company, including P/N 174039 S/N 0001-0012, P/N 174010-01 and 174010-03 with certain serial numbers, and P/N ZMR 100 series S/N 6603-7234. The directive mandates the removal and replacement of the diaphragm assembly, with a requirement to mark the modified masks with an "M" to indicate compliance. While the replacement process must generally be performed by returning the mask to the manufacturer, certain ZMR 100 series masks can be modified in the field following specified maintenance manuals. Compliance with this directive is required within 100 hours of service after June 30, 1981, with previously reworked masks considered compliant. This legislation is applicable across the Commonwealth of Australia, overseen by the Civil Aviation Safety Authority, and is integral to ensuring the safety of aviation operations within the country.
Key Provisions
The key provisions of the AD/OXY/3 Amendment 1 (section 1) detail specific requirements for the replacement of diaphragm assemblies in Puritan-Bennett Aero Systems Company oxygen masks. Firstly, the directive mandates the removal and replacement of the diaphragm assembly P/N F334-1001-1 with a modified version that includes a diaphragm and plate assembly P/N F334-1003-1 Revision E (section 1). After this modification, the masks must be permanently marked with the letter 'M' at the end or beneath the mask serial number, which is located on the left-hand side of the hardshell or on the back surface of the head harness, depending on the model (section 2). The replacement should generally be carried out by returning the mask to Puritan-Bennett Aero Systems Company; however, for certain models, it can be done in the field following the relevant ATA Component Maintenance Manuals (section 3).
These requirements impose obligations on operators and owners of the specified oxygen masks to ensure compliance with the directive. They must replace the diaphragm assemblies as directed, mark the masks appropriately, and follow the stipulated procedures for replacement, which may include sending the masks to the designated service provider or performing field maintenance if permitted (section 3). Operators must also keep records of compliance and modifications to demonstrate adherence to the directive.
The Act does not explicitly state any offences, penalties, or civil/criminal consequences for breach of these requirements within the provided text. However, non-compliance with Civil Aviation Regulations 1998, which govern airworthiness and safety, can lead to severe penalties under other sections of the Civil Aviation Act 1988. These can include fines, imprisonment, or both, depending on the severity of the breach and its impact on aviation safety. Operators and owners must ensure strict adherence to all regulatory directives to avoid these potential consequences.