After several months of testing and revising the previous engineering brief, the new EB has been signed and made effective as of December 26, 2018. To recap, the purpose of EB83A is "[to provide] information and guidance for standard methods to be employed when using stainless steel or coated carbon steel bolts to secure light fixtures to L-868 light bases." Most of what was said in our anticipatory letter from last year still applies, however, a few important changes are worth noting.
Instead of issuing a standard clamping force across the board for all airports, the FAA has released a series of equations that airport management can use to calculate the appropriate clamping force. These calculations are based on the governing aircraft at a given airport. GBA Components is currently in the process of compiling data from aircraft manufacturers and creating a chart with all of this information. Our goal is to know, at a glance, how much clamping force should be applied to the light fixture bolts at any given airport. We hope to have this completed in the near future in order to lessen the burden on our customers.
Galvanic corrosion is also discussed at length in EB83A. The brief states, "Carbon steel bolts must be coated or treated in such a manner that the bolt will inhibit galvanic corrosion on the bolt and the light fixture and base it secures." This implies that the use of bare stainless steel and zinc plated bolts is not recommended since there will be galvanic action between the dissimilar metals in the bolt, light fixture, and light base. The brief also states, "To preclude galvanic corrosion, use of coated stainless steel or coated carbon steel bolts should be considered. Coatings effectively insulate the bolt from both a zinc coating and an aluminum light fixture and preclude galvanic corrosion."
If you would like to read through Engineering Brief 83A, it can be found at FAA.gov, or by clicking here. If you have any questions regarding the new brief, or would like more information on our products, please feel free to give us a call at (312) 690-3200, or get in touch with us through our website at https://gbacomponents.com/contact/. We hope that everyone is having a great start to the New Year, and we look forward to hearing from you.