英文阅读：飞机上的“黑匣子”
飞机失事后经常被提及的一个词就是“黑匣子”。这个事实上为橙色的“黑匣子”是用来记录飞机飞行过程中一些重要数据的工具，通过里面记录的相关数据，调查人员可以分析出失事原因。Black boxes - which are actually orange - are a group of data collection
devices mounted in the tail of an aircraft.
Under internationally agreed regulations, commercial aircraft must carry
the equipment to record the performance and the condition of the aircraft in
flight.
The recorders are housed in immensely strong materials, such as titanium,
and insulated to withstand a crash impact many times the force of gravity,
temperatures of more than 1,000 deg C for up to 30 minutes and the immense
pressure of lying on the seabed.
One manufacturing test for data recorders involves firing them from a
cannon into a wall to simulate an aircraft suffering a catastrophic crash
landing while traveling at hundreds of miles an hour.
The recording material is itself insulated against accidental deletion and
the corrosive effects of sea water.
Modern black boxes record up to 300 factors of flight including:
Airspeed and altitude
Heading and vertical acceleration
Aircraft pitch
Cockpit conversations
Radio communications
The safety precautions are designed to ensure, theoretically, that accident
investigators will be able to recover the recorders, compile a full picture of
an aircraft's last moments from the recordings and then accurately explain what
went wrong.
Origins
Australia lays claim to the development of the flight recorder after one of
its scientists dreamed up the concept following the birth of commercial jet
aircraft in the 1950s.
In 1953, jet flight experts were struggling to understand why a number of
Comet airliners had inexplicably crashed, throwing the entire prospect of
commercial jet air travel into doubt.
A year later Dr David Warren, an Australian aviation scientist, proposed a
flight recording device and by 1958 he had produced the prototype "ARL Flight
Memory Unit".
That first version was slightly larger than an adult hand but capable of
recording some four hours of cockpit conversation and instrument readings.
To Dr Warren's surprise, the device was at first rejected by aviation
authorities as having "little immediate direct use in civil aircraft" while
pilots described it as a "Big Brother" spying on their actions.
On taking the device to the UK, Dr Warren was enthusiastically received
and, following a BBC report on the device, manufacturers came forward to take
over the project.
Similar developments had by this stage also begun in the United States and
by 1960 the first steps were being taken to make the devices mandatory.
Computers have now replaced magnetic tape, meaning the devices can record
more data and are far more likely to survive an impact.
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