STEM与日常科技·英语30篇（2）

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飞机黑匣子为什么耐摔

Black boxes — actually bright orange for visibility — contain two separate recorders: one for cockpit voice and another for flight data.
Each unit is wrapped in a 1-inch-thick aluminum shell, then layered with heat-resistant insulation and a stainless-steel outer casing.
They must survive impacts up to 3,400 times Earth’s gravity, equivalent to hitting concrete at over 300 mph.
Temperatures inside the recorder must stay below 270°C during a fire lasting one hour at 1,100°C.
Underwater locator beacons automatically activate upon contact with water, pinging at 37.5 kHz for up to 30 days.
Crash tests include dropping units onto steel plates, crushing them with hydraulic presses, and submerging them in saltwater tanks.
Manufacturers embed memory chips in shock-absorbing gel to prevent vibration damage during turbulence or hard landings.
Despite their name, black boxes are never black — their color and reflective tape help search teams find them in wreckage or ocean mud.
Newer models record more parameters — up to 2,000 — including pilot inputs, engine vibrations, and cabin pressure changes.
Even after decades underwater, engineers have recovered readable data from recorders using specialized cleaning and signal-recovery tools.