The bulletin
Text extracted from the PDF.
FAA Aviation Safety
SPECIAL AIRWORTHINESS
INFORMATION BULLETIN SUBJ: Propeller Hub Section SAIB: 2026-04 Date: February 18, 2026 This is information only. Recommendations aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin (SAIB) advises owners and operators of Hamilton Sundstrand Corporation Model 54H60 propellers of unauthorized electric arc scribe part markings on the barrel surface which may make them susceptible to cracking.
At this time, the airworthiness concern is not an unsafe condition that would warrant an FAA airworthiness directive (AD) action under Title 14 of the Code of Federal Regulations (14 CFR) part
39.
Background
Collins Aerospace, formerly Hamilton Sundstrand, issued Service Information Letter (SIL) 866, Revision 1, dated January 24, 2023, to provide instructions for inspecting part markings to identify barrels marked using methods that may make them susceptible to cracking and outline corrective actions if necessary. It was determined that several types of markings have been utilized on the barrel surface. The primary marking methods include electric arc scribe, vibrapeen, acid etching, and paint.
Among these methods, the most concerning is the unauthorized use of the electric arc scribe performed with aggressive settings. This method creates local pitting or pockmarks of melted material, typically recognizable as black burning that is non-uniform in depth, size, and spacing.
Vibrapeen and acid etching can also be problematic as described in Collins Aerospace SIL 866, Revision 1.
Recommendation
The FAA recommends all owners and operators of Hamilton Sundstrand Corporation Model 54H60 propellers follow the instructions outlined in Collins Aerospace SIL 866, Revision 1, dated January 24, 2023, to determine the type of markings on the barrel and any corrective actions if necessary.
In some cases, overhauled barrels have been stripped, replated, and re-marked making it difficult to identify all the marking methods used throughout the barrel’s service life. For questions contact Collins Aerospace as specified in SIL 866.
For Further Information Contact
David Bergeron, Aviation Safety Engineer, FAA; phone: (860) 386-1805; email: ecb-cos@faa.gov.
For Related Service Information Contact
Collins Aerospace Company; website: collinsaerospace.com/support; email: crc@collins.com.