In aerospace, there are three different types of recording devices in an aircraft – a flight data recorder (FDR), a cockpit voice recorder (CVR), and a combined cockpit voice and flight data recorder (CVFDR). Together, these devices document an aircraft’s flight history and provide vital information for flight investigations and fleet managers.

Flight Data Recorders are Orange, Not Black

FDRs, also known as black boxes, are actually coloured bright orange to assist in locating these systems in an aircraft’s recovery efforts. The term black box began during WWII by British troops, during the integration of radio, radar, and electronic navigational aids during aircraft combat. Initially, these boxes were designed in non-reflective black box housings. Today, FDRs are now coloured with orange paint to provide high visibility for swift location and identification during an aircraft recovery.

FDRs receive inputs from specific data frames via flight-data acquisition units (FDAU). These data frames record flight parameters, such as control and actuator positions and engine information. Most regulatory requirements state a minimum of 88 parameters are to be recorded while an aircraft is in flight.

Other parameters can be recorded and then analyzed to predict and detect maintenance issues onboard a plane to avoid a plane systems’ failure. To protect the information on these devices, flight recorders are designed to withstand a crash and are usually installed in the tail section of an aircraft.

Early Aircraft Flight Data Recorder Systems

In the 1940s, the first modern FDR called the “Mata Hari,” was designed by Finnish aviation engineer Veijo Hietala. It was engineered to record all critical details during flight tests for Finnish army fighter aircraft. This version of the FDR was popularized following successful uses during World War II by British and American air forces.

A black box from the side of commercial airplane.

Flight Data Recording Requirements Today

Inflight data recorders are required by global aerospace regulatory authorities. Global FDR requirements are overseen by the International Civil Aviation Organization (ICAO) and have been mandated in the United States since 1967.

Recommendations and standard practices relating to FDRs are outlined in ICAO Annex 6 and relate to industry standards for crashworthiness and fire protection specifications. In the US, the Federal Aviation Authority (FAA) provides regulatory measures on all aspects of aviation in US airspace. The FAA states their Technical Standard Order is based on European Organisation for Civil Aviation Equipment (EUROCAE) documents, which is the industry authority that standardizes performance requirements within most air authorities.

EUROCAE standards currently specify that FDRs must withstand an impact shock of 3400 g’s. Also outlined by the EUROCAE, an FDR must be designed to withstand penetration, static crush, high and low temperatures, deep-sea pressure, fluid immersion and retain its ULB attachment.

EUROCAE ED-112 (Minimum Operational Performance Specification for Crash Protected Airborne Recorder Systems) outlines the minimum requirements for FDR devices. This includes cockpit audio, images, and communications, navigation, and surveillance systems.

To aid in accident investigation, “FLIGHT RECORDER DO NOT OPEN” must be lettered on one side in English. FDRs must also be equipped with an underwater locator beacon, which automatically activates during an accident in water.

The Growth of CVFDR Technology

Rapid advancements in CVFDR technology have aided flight investigations, as today’s recorders are trending smaller and lighter, with more storage space for recording hours. 

Throughout global airspace, CVFDR requirements are steadily increasing and adapting to more powerful technologies. The European Union Aviation Safety Agency (EASA) is currently leading the way with recent requirements that require all CVFDRs installed on fixed-wing and rotorcraft airframes to be in the solid-state form (replacing the magnetic tape-recording method). Additionally, EASA now requires all aircraft with a maximum takeoff weight (MTOW) of 59,500 lbs., with a Certificate of Airworthiness (CoA) on or after Jan. 1, 2021, must be equipped with a 25-hour CVFDR.

With additional EASA and FAA requirements now being phased in to capture data link messaging to and from an aircraft, one can truly see how far CVR technology has advanced over the last few decades.

The SENTRY Flight Data Recorder Platform

Flight Data Systems provides several options to capture and record flight data.

In 2020, Flight Data Systems unveiled the SENTRY series of Cockpit Voice and Flight Data Recorders (CVFDR). This unique design is FAA TSO approved and is the world’s smallest, lightest, and lowest power FDR series that is fully EUROCAE ED-112A compliant. Today, the SENTRY is an industry leader in SWaP optimizations, designed to maximize power restraints onboard an aircraft.

The SENTRY is ideal for all aviation platforms, including civil, military, fixed-wing, rotorcraft, and unmanned aviation. It offers digital and analog interfaces and integrates seamlessly into all aircraft types. Its multiple configuration options include FDR, CVR, data link, recorder independent power and CVFDR systems.

SENTRY’s Unique Field-Programmable Gate Array (FPGA)

The unit’s software-free technology allows for aircraft-specific configurations, customization, and expansion capabilities for installation onboard an aircraft. In the SENTRY design, all functionality is implemented solely in a programmable logic device (PLD) with no required software.

Furthermore, the field-programmable gate array (FPGA) based design allows performance optimization with less power consumption. Since FPGA’s do not go obsolete nearly as often as microprocessors, operators can keep their non-recurring engineering (NRE) costs down. The FPGA’s also allows for a partition of a design, which can make re-certification much quicker when a design change is made and if the design change is limited to one partition.

Other FDR and CVFDR systems today do not use this FPGA design. FPGAs are used as companion devices in traditional systems to improve functionality (such as an ARINC 717 or ARINC 429 decoder) and are coupled with a standard processor, which performs traditional high-level processing tasks, including storage, wear leveling, and built-in testing.

Additionally, Flight Data Systems’ Modular Acquisition Unit (MAU) supports the SENTRY’s expansion capabilities, which converts the unit’s capabilities into a data acquisition and crash recorder system, and more.

Conclusion

The evolution of FDRs and CVFDRs throughout the history of air travel has provided aerospace with more powerful technologies to ensure stable and secure data for flight investigations. The cost of flight investigations is substantial, and operators today are requiring information faster and more effectively. As these systems have become more critical, their usages have also increased, including providing fleet maintenance reports for motoring aircraft health and improving safety. Over the past century, FDRs have ultimately improved aerospace safety and continue to deliver more insights from every flight to guide future aerospace developments.

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