They’ll be lucky to get a viable data recorder out of that debris field.
“They’ll be lucky to get a viable data recorder out of that debris field.”
There are several tests that make up the crash-survival sequence:
•Crash impact - Researchers shoot the CSMU down an air cannon to create an impact of 3,400 Gs (1 G is the force of Earth’s gravity, which determines how much something weighs). At 3,400 Gs, the CSMU hits an aluminum honeycomb target at a force equal to 3,400 times its weight. This impact force is equal to or in excess of what a recorder might experience in an actual crash.
•Pin drop - To test the unit’s penetration resistance, researchers drop a 500-pound (227-kilogram) weight with a 0.25-inch (0.64-centimeter) steel pin protruding from the bottom onto the CSMU from a height of 10 feet (3 meters). This pin, with 500 pounds behind it, impacts the CSMU cylinder’s most vulnerable axis.
•Static crush - For five minutes, researchers apply 5,000 pounds per square-inch (psi) of crush force to each of the unit’s six major axis points.
•Fire test - Researchers place the unit into a propane-source fireball, cooking it using three burners. The unit sits inside the fire at 2,000 degrees Fahrenheit (1,100 Celsius) for one hour. The FAA requires that all solid-state recorders be able to survive at least one hour at this temperature.
•Deep-sea submersion - The CSMU is placed into a pressurized tank of salt water for 24 hours.
•Salt-water submersion - The CSMU must survive in a salt water tank for 30 days.
•Fluid immersion - Various CSMU components are placed into a variety of aviation fluids, including jet fuel, lubricants and fire-extinguisher chemicals.
http://science.howstuffworks.com/transport/flight/modern/black-box5.htm
The flight data recorder and cockpit voice recorder are very tough, engineered to withstand crash conditions. Even if the outsides are totally smashed, the disks are usually safe and can be removed, put in a working unit and analyzed..............