P&G aircraft cockpit voice recorder (black box) teardown

This is probably going to be the last aviation related teardown video but to finish this teardown series I’ve got something pretty cool; a black box from an RAF Nimrod MRA4 which was a failed project and numerous aircraft were built but were never delivered to the RAF and were later scrapped. This one does show some signs of wear and tear although it may well be damage due to storage and this unit has never actually been used. The locator beacon on the front which is a circular tube containing a battery and the radio beacon itself is missing however everything else is present.

Penny & Giles Nimrod MRA4 cockpit voice recorder photo.

It is a solid state recorder utilizing 128Mb of flash memory to store the audio recordings and it is buffered and compressed by the electronics to reduce file size and therefore increase recording time. I found the recorder to be functional as I managed to power it up but unfortunately I was unable to access the recordings or the built in serial menu via the RS232 port on the front panel.

The recorder is powered by two microcontrollers; a Philips 80C51 clone which serves as the boot processor and a 32 bit AMD AM29200-20 as the main application processor. The boot ROM is stored in the 8051 and there is a separate ROM for the 29200 CPU which looks like it contains the operating system (probably some kind of RTOS) as well as some flash for containing the application that actually runs the device. This looks like it is flashed / updated via the serial port on the front panel. I managed to dump some of these ROMS so I could get some idea how it works.

A youtube video of it is here and below you can also find a photo album showing the internal components and circuit boards.

 

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