A European customer approached Matt Black Systems with a requirement for a display panel for a fuel regulation system they were developing. This was for the control of additional fuel tanks to be fitted to Helicopters. The panel needed to incorporate the following features:
Green NVIS-compatible illuminated legend (to MIL-STD-3009)
Yellow NVIS-compatible warning annunciators, to be secret-til-lit and sunlight readable (also to MIL-STD-3009)
Three-digit 7 segment displays, in two positions
Flip-cover protected mode switch
Electrically grounded backing plate with Dzus ¼-turn fasteners
The 7-segment displays also needed to be able to display the fuel level in a variety of units – Kg, Lb, Litres, Gallons etc. This was achieved through supplying a set of unit plates with each panel, to automatically switch the electronic settings, as well as displaying the unit type clearly on the front of the panel. These plates can be changed in a few seconds.
The panel also had to include circuitry to set appropriate illumination levels based on stepped input voltage levels for the annunciators and 7-segment displays. However, the general legend had to display the same curved dimming characteristics of a filament bulb, while actually using LEDs for improved life and lower power use and heat losses.
Due to the rotary-winged application, the panel assembly was obviously designed to survive a harsh, high-vibration environment.
As well as designing and manufacturing the panel assemblies, Matt Black Systems was also able to supply a Failure Mode Effects Analysis, and Mean Time Between Failure calculations to MIL-HDBK-217F.