There is limited space available to install numerous avionics boxes with the caveat that each box is a line replacement unit (LRU). Access to enable the removal of the boxes is limited, and it is critical that no tools and/or loose parts exist to ensure that no damage is done to aft-located components. Boxes are mounted on pallets and secured by captive screws with a tool. Most installation/removal requires two technicians.

The Avionics Rail Mount System was designed to more easily allow avionics and electronics to be installed in aerospace and other structures. The system simplifies the placement, installation, and removal of avionics boxes, and allows self-aligning. It is lightweight and minimizes the number of fasteners needed. It is also ergonomically correct for a technician to install and secure, or remove and replace objects.

The system consists of the “C”-profile rail/track, a cartridge with spring-loaded lockpin that slides in the track at spaced cutouts, and a threaded cleat that rides in a slot on the back of the cartridge, allowing for self-alignment. Each installation consists of a minimum of two parallel rail/track assemblies. The rails/tracks are installed into the structure, and the cartridge/cleat assembly is installed onto the hardware being placed in the structure.

Once the hardware is ready to be installed, the cartridges are slid onto the rails/tracks via cutouts, and ridden down the rail/track to their desired locations. Once in place, the spring-loaded lockpin engages in a pre-drilled hole, locking the hardware down. Hardware can be used in a circular, linear, or radial configuration.

The system’s self-aligning cleat allows mounting of a flat or box-shaped component on a curved or irregular surface. The notched rail allows the technician to place the full weight of the installed component directly onto the rail while installation is carried out. The technician does not need to hold the component while attempting to insert a fastener.

This work was done by Jackie Thomas and Lawanna Harris of Marshall Space Flight Center. For more information, contact Ronald C. Darty, Licensing Executive at the MSFC Technology Transfer Office, at This email address is being protected from spambots. You need JavaScript enabled to view it.. Refer to MFS-32615-1.


NASA Tech Briefs Magazine

This article first appeared in the December, 2015 issue of NASA Tech Briefs Magazine.

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