In aircraft, the flight data recorder (FDR) and the cockpit voice recorder (CVR) are used to record aircraft and pilot behavior in order to analyze accidents, and are usually called "black boxes" by the news media.

The main purpose of the device is to reduce the manufacturer's liability by correctly assigning blame to the failing assemblies or persons. The famous, secondary use is to analyze accidents to prevent future failures.

Traditional black boxes use potentiometers attached to strings. The strings are actually steel wire, bolted to the controls and flight surfaces. As the surfaces move, the resistances of the pots change, changing the frequency of an oscillator. The oscillator's electronic howl is wired to a recorder. The howl is better than just recording a voltage because the howl cannot be affected as easily by stray currents or magnetic fields. Since the tape or wire's recording speed can be erroneous, usually the data is recorded for a fixed time, and then the howls are turned off for a bit. This turns the howls into countable electronic pulses on the tape or wire, with higher howls having more pulses per interval. The pulses, along with the pilot's incoming and outgoing audio, are recorded on a recirculating loop of magnetic tape or wire. In the earliest recorders, wire was preferred because it is more resistant to fire. Later, high-temperature magnetic tape and insulated housings were developed.

Digital black boxes usually eavesdrop on the aircraft's main data bus. They record the most significant 8 bits of (usually) 88 parameters, including the control and actuator positions, engine information and time of day. Generally each parameter is stored once per second, though some units store "bursts" of data if it begins to change quickly. Most black boxes record more than a day's worth of data. Since a day has 86,400 seconds, a basic black box only needs about 7.6 megabytes of data storage. Most units use flash memory, which only permits memory to be written about 100,000 times. Although this would be impractical in a general purpose computer, a black box is only rewritten once per day, so it will last 270 years.

Traditionally, black boxes are placed in the tail of the aircraft. In this position, the entire front of the aircraft acts as a "crush zone" to reduce the shock that reaches the recorder. Also, modern black boxes are double wrapped, in strong corrosion-resistant stainless steel or titanium, with high-temperature insulation inside.

Black boxes are often poorly maintained, because they are not critical to flight. There is a growing sentiment that they should be reliable, solid-state digital systems. Additionally, since they are often crushed into unreadable pieces, or never located, some modern units are self-ejecting, and brightly colored, with radio and sonar beacons.

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