A typical traditional CVR is 16 cm (6.3 in) in height, 12.7 cm (5.0 in) in width and 32 cm (12.6 in) in depth.
It weighs 4.5 kg (10 lbs).
The black box recorder tends to survive partly because of the location. They’re placed at the tail of the plane, far from the engines and fuel tanks and located where they will be generally protected from impact by the rest of the airplane.
Secondly, the actual recording chip itself is potted inside a steel tub, and is capable of surviving high levels of deceleration. The material surrounding it also provides some degree of protection against fire and water immersion. An airplane built to the same degree of durability would be too heavy to fly, and still wouldn’t protect the people inside from being killed by the impact forces when it crashed anyway.
This can be easily understood by figuring out the construction of the black box itself with pictorial representations.
- It is located at the tail end of the aircraft mainly because it is assumed that the tail end unlike the front of the plane (which is the crush zone) is likely to keep the boxes comparatively safe.
- See this diagram. The parts that I’ve highlighted in yellow give you the specifics of how sturdy this thing actually is.
- FDRs are double coated in titanium or stainless steel.
The important part that contains the memory boards, the CSMU (look below), is shot out of an air cannon to create an impact of 3,400 Gs and then smashed against a target. It is subjected to a 227kg weight with a pin attached to it, which is dropped onto the unit from a height of three metres. Researchers try to crush it, destroy it in an hour of 1,100 degree Celsius fire, submerge it in a pressurized salt water tank, and immerse it in jet fuel.
