Keeping Fasteners Safe

Standard parts – particularly fasteners – continue to be a topic that is being discussed by regulators on both sides of the Atlantic.  We’ve had private conversations with both FAA and EASA executives on this issue.

The Issue

In 2013, EASA published a Safety Information Bulletin (SIB) entitled “Defective Standard Hardware – MS21042, NAS1291 and LN9338 Self-Locking Nuts, and NAS626 Bolts.”  This European SIB highlighted defects in certain self-locking nuts, and certain bolts.  In each case, the fasteners were standard parts.  EASA recommended that those who use these fasteners should visually inspect them for surface irregularities, such as gouges or cracks, before use.  EASA also recommended testing 1% of each lot received as a means of identifying non-conformities.

In 2014, the FAA published a follow-on document (Standard Hardware, AN, MS and NAS Fasteners, FAA SAIB HQ-14-16 (April 28, 2014)) that expanded on the EASA SIB.  Further investigation had shown that the non-conformities were attributed to hydrogen embrittlement and other other latent manufacturing defects.  Although this information was not published, industry rumor suggested that the hydrogen embrittlement was the product of inadequate heat treating.

The FAA has described the defects in these fasteners as “emblematic of potential flaws in other standard hardware.”  In conversations with both FAA and EASA executives on this issue, the root cause opinions appear to be uniform – when many military specification standards were retired by the U.S military, they were then republished by civil standards organizations for continued use in civil aircraft (e.g. AIA publishes the National Aerospace Standards).  After that time, the Department of Defense no longer provided oversight to these standards.  The civil standards organizations do not certify, monitor compliance or perform surveillance of parts produced to these standards (nor of their manufacturers). The responsibility for compliance with these standards and specifications lies with their respective manufacturers – and nearly all of the time, these manufacturers are doing the right thing – they are ensuring that their standard parts meet the requirements of the applicable standards.  But events have shown that a tiny sliver of bad actors can cause unwanted problems, and some people in the government feel that this lack of oversight has left an opportunity for improper manufacturing.

How can we address this lack of oversight economically?  By considering other forms of oversight and assurance.

There is a solution.

Many fastener distributors are accredited to the ASA-100 standard.  The ASA-100 standard includes a requirement that fastener distributors perform visual inspection on fasteners, and maintain batch/lot segregation of fasteners.  This requirement establishes a second set of eyes to help ensure that fasteners are not subject to obvious flaws.

Thus, buying standard parts from ASA-100 accredited distributors helps to ensure the integrity of the fasteners that you are receiving.

The FAA and EASA are both continuing to look at this issue.

We recently met with EASA and proposed that their regulatory structure already is developing a framework for embracing a solution.  EASA published Opinion 2013-12 which included a recommendation for the updating of EASA 145.A.42.  The new language would include enhanced requirements for acceptance of components:

The organisation shall establish procedures for the acceptance of components, standard parts and materials for installation to ensure that components, standard parts and materials are in satisfactory condition and meet the applicable requirements of point (a).

In the proposed GM3 145.A.42(b)(1) that would accompany this regulatory change, Part 145 organizations would be permitted to rely on “other-party” surveillance of suppliers.  This would include reliance on the surveillance performed under the AC 00-56 program and under the ASA-100 program.  The proposed GM is published in the EASA Comment Response Document (CRD).

In light of the fact that ASA-100 already includes fastener surveillance, EASA could use this upcoming promulgation as a tool to better enhance standard fastener oversight by endorsing fastener surveillance as a required element for inclusion in the GM.  By using the distribution community as a second set of eyes, EASA and the FAA would have an inexpensive mechanism for helping to catch problems in cases where fasteners are not properly produced to the expected standards.

Distributor accreditation has been successful in addressing unapproved parts issues, by creating a knowledgeable group with appropriate quality management systems that are designed to identify those sorts of problems.  This model has already been successfully expanded to fastener issues within the ASA-100 community.  This model can also be further expanded to make use of the entire distributor accreditation community as a second set of eyes, watching for fastener issues.

%d bloggers like this: