How do we elucidate the cause of the accident on the "black box" of the aircraft?

For passenger aircraft flying with many passengers, record operations and actual movements of the aircraft almost exceptionallyBlack boxIt is equipped. The black box keeps track of the condition of the aircraft at all times and it is possible to know what kind of situations the former aircraft was in the event of an emergency accident, A movie that describes the state of the movie has been released.

Airplane black boxes, explained - YouTube


American Airlines 587 flight (Airbus A200 aircraft) just after taking off at New York's John F. Kennedy International Airport (JFK airport) on November 12, 2001 crashes in the Queens area on the outskirts of New YorkAmerican Airlines 587 Flight CrashOccurred.


Since the accident occurred just two months after the "September 11 terrorist attacks" in which two aircraft crashed into the New York trade center building, "I wonder if the terrorist attack on the aircraft occurred again" and made the domestic market turbulent It was.


After the accident, a vertical tail winged off the crash machine was discovered from underwater, but this was a great hint to pinpoint the cause of the accident.


American Airlines 587 which took off the airport turned to the left and was about to raise the altitude, but lost control of the aircraft on the way, crashed into a residential area in the Queens District. However, since the vertical stabilizer had fallen in the Jamaica bay in front of it, it was suspected that the aircraft and the vertical tailplane were separated before crashing into the ground.


In addition, in this accident all 260 passengers and passengers died and five inhabitants of the crash site were involved in the accident and died, one was injured.



After the accident, a survey by the National Transportation Safety Commission (NTSB) was conducted to clarify the cause, and the report has been compiled.


Among them, the data played a major role was the numerous data contained in the black box.


An example of a "black box" in which this is installed in an aircraft. It consists largely of two pieces of equipment, and its name is painted in vivid orange color in reality, but in consideration of the time of accident occurrence, a color that is easily found in the field is chosen Because it is. The name "black box" is said to have been named from a state that it is strictly protected and sealed and it can hardly be accessed from outside.


The reason why black boxes started to operate was "the world's first jet airplane" manufactured by De Havyland in the UKDH.106 CometIt was a crash accident that happened. During the two years since operation began, Comet made five consecutive crash accidents due to aerial decomposition and gave the aircraft industry a very big shock.


This continuous crash accident was caused by "metal fatigue" which was not taken into consideration at the time at the time. And in the investigation, the necessity of a device to record what operations and actions were taken at the time of accident, how the aircraft moved, and so on became available.


As a result, a "black box" has been developed to record various situations during flight.


Black boxes are also evolving variously with age. The initial flight recorder said that it wrote several pieces of information on thin metallic band-shaped sheets.


Then, the recording method using magnetic tape appeared next.


And the current mainstream is a data storage method using semiconductor memory.


The black box consists of "Cockpit Voice Recorder (CVR)" and "Flight Data Recorder (FDR)".


Among them, a cockpit voice recorder is a device that records main voices in the cabin. CVR currently widely used can record sounds up to two hours before the accident occurrence.


This recorder records the contents of the two pilots and the voice in the cockpit room on four channels, so that you can grasp the situation by playing back later on separately.


In the conversation inside the cockpit that was recorded by American Airlines 587 flight, just before the accident is left that the PIC is talking about "a little turbulence?"


This turbulence was triggered by Japan Airlines flight 47 (JFK to Narita) which took off just before the American Airlines 587 flightAft turbulenceIt was what was called. Flight 47 was a large aircraft Boeing 747 "Jumbo", and because the speed was low at takeoff speed, backward turbulence that occurred was also big. However, it is not uncommon to encounter a backward turbulence caused by an aircraft going ahead.


Therefore, attention was gathered in the information obtained by "flight data recorder" which records the state of each part of the aircraft.


The flight data recorder that was installed in the falling machine was designed to record data of the past 25 hours, such as the attitude of the aircraft and the state of the equipment, for the past 25 hours.


Based on these data, the accident investigation committee will find out what happened to the aircraft by reproducing the operation and movement of the aircraft at the time of the accident with a computer.


And some of the obtained data is this. The data from JFK airport takeoff to crash is displayed, but it turns out that unusual operation was done in 10 seconds just before the accident occurred.


Particularly noteworthy data is the operation of "rudder" indicated in yellow. This was operated by the co-pilot, but you can see that just before the accident is greatly moved left and right.


This was operated by attempting to restore the aircraft that was disturbed in the posterior turbulence encountering the backward turbulence, but on the contrary this operation caused a heavy load on the vertical stabilizer, which could not be tolerated, so that the root I broke away from it and dropped out. And because of this, the American Airlines 587 flight lost control and crashed.


In this way the cause of the crash of American Airlines 587 was revealed by circumstantial evidence and black box data. If you do not have a black box and you have to investigate with only the remains of the aircraft, it is not difficult to imagine that investigating the cause was difficult to compare.


The black box is usually mounted around the base of the vertical stabilizer behind the aircraft. This is because the probability of receiving direct damage in the event of an actual accident is low, the impact is absorbed by the aircraft when colliding with the aircraft, and less impact is applied to the black box behind.


The body of the black box is made of durable metal such as titanium. It is also protected by materials that can absorb shocks and heat insulation to protect memory devices from impacts and fires that occur during accidents.


By taking several countermeasures like this, black boxes are found at many sites even in the event of an accident, and the cause of the accident has been clarified.


In addition, the black box has a mechanism that automatically transmits radio wave signals and sound wave signals for searching when an accident occurs. At the time of searching, by using a receiver that senses this signal, ingenuity is adopted that allows you to discover a black box sank in the bottom of the ocean when it crashes to the sea.


However, it still occurred in March 2014Malaysia Aviation 370 flight crashAs in the case where the black box falls into the deep ocean where it is difficult to search for radio waves, or when you run out of the battery of the main unit, it will be difficult to find and haul. For that reason, it is now advocated a method of constantly sending data stored in a black box to the ground via artificial satellites and storing it.


Nonetheless, it is also advocated that opposition that privacy is impaired in the case of private jet, for example, by "this position always supplements the position of the airframe from the ground". Whether priority is given to countermeasures at the time of the accident or whether the secret of the individual should be given priority is considered to be the argument which will never end.