Black boxes have been getting a significant amount of attention lately. From the NHTSA’s call for mandatory use of black boxes in automobiles to the discovery of the black box from the Air France flight that crashed into the Atlantic Ocean last year, the media has been full of black box references. Modern black boxes are, of course, largely electronic devices. But that was not always the case. Earlier versions of the black box (or flight data recorders as the airline versions are called) — many of which are still in use today — are interesting examples of mechatronics.
As a case in point, consider the FA-542 made by Sundstrand. In the FA-542, four transducers (two pneumatic and two electronic) were used to drive foil recording arms. Airspeed and altitude data came in via plumbed lines directly to the flight data recorder to pneumatic actuators positioned alongside motor drives for actuation of recording of pitch/bank. Four scribing arms were positioned width-wise across an Iconel foil roll to record four flight parameters. The electronics chassis in the FDR housed power conditioning, signal conditioning and transport devices.
David Carey of UBM TechInsights (UBM is the parent company of Design News) performed a teardown of the FA-542 as part of the Embedded Systems Conference in 2009. To see images of the inside of that black box and read a full rundown of its constituent parts and their interaction, visit this article on the Design News Website.