Everyone’s heard of the “black box”. Officially known as the Flight Data Recorder (FDR), it’s a mandatory piece of equipment on commercial aircraft. The FDR is instrumental in investigating incidents or crashes, and is specifically designed to survive should the aircraft be destroyed. The search for the so-called “black box” often dominates the news cycle after the loss of a commercial aircraft; as finding it will almost certainly be necessary to determine the true cause of the accident. What you probably haven’t heard of is a Quick Access Recorder (QAR).

While it’s the best known, the FDR is not the only type of recording device used in aviation. The QAR could be thought of as the non-emergency alternative to the FDR. While retrieving data from the FDR usually means the worst has happened, the QAR is specifically designed to facilitate easy and regular access to flight data for research and maintenance purposes. Its data is stored on removable media and since the QAR is not expected to survive the loss of the aircraft it isn’t physically hardened. In fact, modern aircraft often use consumer-grade technology such as Compact Flash cards and USB flash drives as storage media in their QAR.

Through the wonders of eBay, I recently acquired a vintage Penny & Giles D50761 Quick Access Recorder. This was pulled out of an aircraft which had been in service with the now defunct airline, Air Toulouse International. Let’s crack open this relatively obscure piece of equipment and see just what goes into the hardware that airlines trust to help ensure their multi-million dollar aircraft are operating in peak condition.

It’s Still Built Like a Tank

The Quick Access Recorder might not be intended to survive in a crash, but it’s still an expensive piece of hardware installed in an even more expensive aircraft, so this thing is still built like a tank. The case itself is best described as a metal shoe box: the bottom and sides have all been expertly welded together to create one continuous piece of metal, and only the top “lid” can be removed by loosening twelve captive screws around its perimeter.

The front of the QAR has a handle and some locking tabs, so it looks like this device was meant to slide into an electronics rack of some type rather than being permanently mounted. There’s a power LED down at the bottom, but everything else is covered by a locking door during normal operation. Under the door is a slot for the tape the device stores its data on, status LEDs marked BUSY and READY, and an Eject button. Interestingly the Eject button is electronic rather than being connected to a physical mechanism, but it did help explain why the QAR arrived to me with a tape stuck inside of the drive.

Data Cartridge

I was able to remove the tape from the QAR without too much trouble, but unfortunately it doesn’t provide us with a whole lot of information to go on. The label says it was put …read more

Source:: Hackaday