When an aircraft is in an accident, in addition to finding survivors, search and rescue personnel have a key point of looking for black boxes.
First, the evolutionary history of black boxes and the current state of technology
The black box is a flight data recorder, dating back to 1957, when the FEDERAL AIR TRAFFIC required that aircraft with a takeoff weight of more than 9 tons must be equipped with a flight recorder that is resistant to high temperature and pressure.
Picture interpretation: the first generation of black boxes
Picture interpretation: The black box used now
In the late 1980s, there was a digital black box with a tape length of 150 meters, which could record 11 parameters for a total of 25 hours of data, and after 2002, a black box that could record 88 parameter recorders and 2 hours of cockpit call records was developed, which is currently on the Boeing 737. Currently, the enhanced recorder installed on the Boeing 787 can record 2,000 parameters and 50 hours of data. In terms of physical pressure resistance, the standard is 1100 °C to maintain for 30 minutes to 60 minutes, 6.5 milliseconds to resist 3400 G shock, soaked in seawater for 30 days, can resist 6000 meters deep pressure, etc.
Picture interpretation: Position on the airliner
Second, why can't the black box record more parameters?
The most critical purpose of the black box is stability, if the equipment is too complex to guarantee that it will still work at critical times. Boeing has also studied the addition of cabin image information in the black box, and there is no large-scale promotion, the problem is that the complex certification review mechanism of the Us and European air traffic tubes, if the new recorder is used, it will be re-certified, which will make the aircraft more expensive.
Picture interpretation: This is the black box on the 737MAX
At present, although the function of the black box is not very advanced, it is certified after all and can meet normal needs. On the issue of increasing real-time data transmission, after the disappearance of MH370, the International Civil Aviation Authority has stipulated that flights should report their location every 15 minutes, but uploading flight data to satellite links is a future trend.
Third, the development trend of black boxes in the future
The development direction of the black box is definitely to achieve cloud backup while storing more parameters, but the two cannot be replaced by each other. Diversification in the form of recordings, such as at least 2 hours of cabin, cockpit images, and voice data, in order to better restore the last-minute state of the aircraft before the accident. It's not hard to achieve all this, it's not about adding some storage space and wiring, but the key is to redesign the relevant structure on the aircraft, re-certify it, and then form a standard for use on the newly produced aircraft, which takes a certain amount of time.