Inside a Cockpit Voice Recorder: FA2100 Teardown Reveals Design Secrets

Recent interest in the MU5735 crash highlighted the importance of flight data recorders, especially the cockpit voice recorder (CVR). This piece documents the teardown of an FA2100 CVR recovered from a junkyard, offering a technical look at its construction.

Why Orange and Called a "Black Box"?

The orange color improves visibility for recovery, while the term "black box" stems from the device’s opaque, mystery‑like nature.

FDR vs. CVR

Aircraft typically carry two recorders: the Flight Data Recorder (FDR) that logs flight parameters, and the Cockpit Voice Recorder (CVR) that records cockpit audio. The FA2100 is a CVR, thus simpler in appearance.

FA2100 Architecture

The CVR consists of three main parts: the Flight Data Acquisition Unit (FDAU), the Crash‑Survivable Memory Unit (CSMU), and an Underwater Locator Device. The FDAU interfaces with the aircraft data bus, the CSMU stores the data, and the locator emits a signal when submerged.

Key specifications include operation from –55 °C to 70 °C, resistance to 5,000 lb pressure, 1 hour at 1,100 °C, 10 hours at 260 °C, and 3,400 g impact without data loss.

Teardown Process

All protective screws and covers were removed, revealing two TI DSP chips, a heavily pot‑filled PCB, and a power board with a ring transformer capable of handling both 28 V DC and 115 V AC. The CSMU was extracted after removing large bolts and shock‑absorbing foam.

Inside the CSMU, a solid‑state memory module was identified, using an Intel SLC flash chip dated 1997, assembled in week 21 of 1998. The main controller is a custom QuickLogic ASIC, similar to an FPGA but fixed‑function.

Capacity and Functionality

The module provides roughly 120 MB of storage, enough for four 30‑minute audio recordings (≈1 MB per minute). The design includes DSP‑controlled DRAM buffers and analog front‑end circuitry for microphone inputs.

Conclusion

The FA2100 CVR’s robust construction, high‑temperature tolerance, and use of legacy Intel flash illustrate the durability required for aviation safety equipment, while its relatively simple architecture makes it an accessible subject for hardware enthusiasts.