The particular focus of the proposed guidance is chemical oxygen generator and this will be particularly important to manufacturers producing chemical oxygen generators, or their parts, under PMA. It is important to to recognize that although the rule says that it only applies to future type certificated aircraft, the changed product rule applies new airworthiness standards to supplemental type certificates (STCs) and other subsequent changes by default.
On March 8, 2011, the FAA published AD 2011-04-09. This AD required that chemical oxygen generators installed inside of lavatories on certain transport category airplanes be rendered inoperative in order to address a security concern. Compliance with this AD resulted in a noncompliance with other regulations, so the AD contained a provision to permit operation notwithstanding those other requirements.
AD 2011-04-09 has since been been superseded by AD 2012-11-09. The new AD required a terminating action to reinstall a supplemental oxygen system in the lavatories that were modified per AD 2011-04-09.
For manufacturers, this focus on the security issues surrounding lavatory chemical oxygen generators has altered the landscape for design approval. Under the new standards, applications for design approval for chemical oxygen generators must demonstrate compliance with the chemical oxygen generator security concerns of 14 C.F.R. § 25.795(d).
The new rule would amend 14 C.F.R. § 25.795, by adding a new subsection that would read as follows:
(d) Each chemical oxygen generator or its installation must be designed to be secure from deliberate manipulation by one of the following:
(1) By providing effective resistance to tampering,
(2) By providing an effective combination of resistance to tampering and active tamper-evident features,
(3) By installation in a location or manner whereby any attempt to access the generator would be immediately obvious, or
(4) By a combination of approaches specified in paragraphs (d)(1), (d)(2) and (d)(3) of this section that the Administrator finds provides a secure installation.
Section 25.795(d) would requires each chemical oxygen generator or its installation to be designed so it meets one of the above-described criteria.
The proposed advisory circular provides means of compliance. It will be important for manufacturers working with chemical oxygen generator systems to ensure that their compliance process for their articles are consistent with the new guidance, or can reasonably be made consistent with the new guidance.