This is why the article about the black box is crap.....here's the specifications for a black box. The WTC exceeded the maximum crush and temperature of the survivability of the Box. As would have the fire in the pentagon. As for Shanksville, well, that one they'd have to explain alot to me...or maybe its still buried in the field, there were little bits of plane and stuff all over the area. Maybe we'll get lucky and when they build the memorial they'll find it if they havent' already.
The Black Box
Introduction:
In the recent years many air plane disasters are reported. This is due to either technical reasons or in cases of terrorism. The Investigation Officers rely on a device known as "The Black Box". This device is used to record the end moments of the crew conversation. This helps in giving the investigation party clue�s of what was the motive behind the disaster. The Black Box saves data about a little more than 30 minutes of conversation and any other audible cockpit noises. It is called the 'black box' due to the secret nature of what it contains. The information inside, especially in the cockpit voice recorder can be very personal and should not get into the wrong hands. For this reason, the information inside is encoded.
The color of the black box is Orange the reason for this color is obvious. It needs to be conspicuous so that it will be easy to find in any terrain. It has to clash with the color of the ocean, mountains, trees or deserts in order for easier location in the event of a crash. It is normal, now for black boxes to have tracing equipment in them. After any airplane accident the National Transportation Safety Board (NTSB) immediately begins searching for two devices. These devices are known as the airplanes "flight data recorder" (FDR) and "cockpit voice recorder" (CVR).
An Australian scientist Dr. David Warren was the man behind this invention. These devices or The Black Box as it is most commonly called is universally adopted as a tool for investigating and preventing airline disasters. He developed this device while he was investigating a series of the world's first jet-powered passenger aircraft, the Comet. He came to reason that the conversation from the crew could help give clues to what actually happened before the crash and come to a conclusion of how the crash actually happened. This came to the conclusion that a device of this sort would be needed on every flight. Sometime earlier Warren had been to an exhibition of technical equipment where he saw the worlds first miniaturized pocket recorder. This device was a German-made Minifon and it recorded sounds on a steel rod rather than a magnetic tape. Warren then installed this feature on his first black box the steel rod could withstand temperatures to red heat without loosing its information. With the advent of the Boeing 747 and the Douglas DC 10 which are sophisticated aircrafts, these planes needed second-generation of more complex recorders of whose separate functions are still in use today (Rizvi, 2001).
In the year 1965 the world's first FDR & CVR devices came into being. The FDR recorded the planes avionics systems, engines, airframes etc. & the CVR stored all sounds that are audible in the cockpit of the aircraft. Data from both these devices are stored on stacked memory boards inside the crash-survivable memory unit (CSMU) (Gresley, 1997).
The CSMU is a cylindrical compartment on the recorder. The stacked memory boards are about 1.75 inches tall. The length of time that can be stored on these is about 25 hours on the FDR and 3 hours on the CVR. These devices gather information from sensors that gather information such as acceleration, airspeed, altitude, flap settings, outside temperature, cabin temperature and pressure, engine performance and more. All of this data is then sent to the flight data acquisition unit (FDAU). This unit gathers all the information from all over the plane gives it to the right unit for it to store. This unit is generally found under the cockpit bay and is the manager for all the data process from the sensors to the black boxes i.e. it tells the system where to store the data that comes from the various sensors on board the aircraft (Gresley, 1997).
The boxes derive they power from one of the two power generator�s which produces its power from the planes engines. One generator is a 28-volt DC power source and the other is a 115-volt, 400-hertz (Hz) AC power source which are the standard power supplies in a planes engine. In almost every cockpit there are inbuilt microphones that are built to record the conversation in the cockpit. These microphones also track down various others noises such as switches being thrown or any knocks or thuds. All these microphones are connected to the cockpit voice recorder (CVR). These sounds are picked up by these microphones and are then transmitted to the CVR where it is digitized and stored. Another device which is in the cockpit is the associated control unit, which provides pre-amplification for audio going to the CVR. Here are the four positions of the four common microphones.
1. Pilot's headset
2. Co. Pilot's headset
3. Headset of a third crew member (if there is a third crew member)
4. Near the center of the cockpit, where it can pick up audio alerts and other sounds.
Most CVR's store the last 30 minutes of the sounds and conversation that are taken place in the cockpit. This is done by a continuous loop which moves a thirty minute tape around and round so that the old data is removed and the new data is written. Each recorder is fitted with an Underwater Locator Beacon (ULB) so that it can be easier to find when an accident happens over the water. This beacon is called a "pinger" is activated when it is submitted when it is submerged under water. It sends an acoustical sound on a 37.5Khz which can be detected by a special receiver. The beacon can transmit its beacon from about 14,000 feet below the surface.
Once the device is found it is taken to the NTSB headquarters in Washington where the data is processed. The processing is done by special sophisticated machines which converts the signals into an understandable format that can be understood by the "Investigating Officer" who helps the Safety Board in determining the probable cause of the accident. During the investigation a committee is formed consisting of members from the NTSB (National Transportation Safety Board), FAA (federal Aviation Authority), operator of the aircraft, manufacturer of the airplane, and the pilot�s unison is formed. This committee makes a written transcript to be used in the investigation. The investigation procedure is one in which many complex time calculations are done. This is achieved by the different time zones that are allocated to the different time zones. This procedure determines where a sequence of events took place. The time sequence is applied to the transcript by the machine. More precise timings for critical events are obtained by using a digital spectrum analyzer. This transcript is made available to the public at the time of the safety board public hearing. The information gathered by these devices are held in the highest confidential manner. As the communication used in the cockpit is of a rather high nature. The congress has required that the Safety board not to release any part of the CVR tape recording. Because of this a high level security is maintained for the CVR and the transcripts.
Below is a specification of a CVR device that is most commonly used.
Time recorded 30 min continuous, 2 hours for solid state digital units
Number of channels 4
Impact tolerance 3400 Gs /6.5ms
Fire resistance 1100 deg C /30 min
Water pressure resistance submerged 20,000 ft
Underwater locator beacon 37.5 KHz
Battery : 6yr shelf life 30 day operation
(abstracted from, Cockpit Voice Recorders�, 2004 )
The following is an ATC transcription of the June 30, 1962 midair collision near Durban , South Africa
Tower-2: Hit something, what is it?
DC-4: I don't know. Just hang on a sec, Mac, we're going to come down as soon as we can.
DC-4: Please keep us in radar contact all the time
Tower-2: Right. That's fine. We're watching you. You're doing fine
DC-4: How are we getting on, from now onwards. (Byrom, 2001)
Tower-2: You are doing fine. You are now eight miles and well seaward of centre line...closing in nicely...Range seven miles. Well to the starboard of the centre line...suggest revised heading of 270 now.
The FDR records many different operating conditions of the flight such as time, altitude, airspeed, heading, and aircraft attitude. This information comes from various areas that are connected to the FDR. When a switch is turned on or off the FDR records that operation. In addition, some FDRs can record the status of more than 300 other in-flight characteristics that can aid in the investigation. With this data the safety board can generate a graphical animation that can help the Investigation Officer to visualize the last moments of the flight before the accident. They create a move like simulation in which engineers and other member so the committee give their own views of what happened and what could be done to further enhance the safety of the aircraft. In America the FAA requires that commercial airlines record a minimum of 11 to 29 parameters, depending on the size of the aircrafts.
"Flight recorders used today employ either magnetic tape or solid-state memory boards, although the trend is toward solid state. The magnetic tape functions like any tape recorder. Solid state recorders are more reliable because they use stacked arrays of memory chips with no moving parts, so there is less need for maintenance, and breakage during a crash is less likely" (Abstracted from SME member manufactures black boxes�, 2000).
The specifications of a Flight Data recorder is
Flight Data Recorder
Time recorded ........................... 25 hour continuous
Number of parameters .............. 5 - 300+
Impact tolerance ....................... 3400Gs /6.5ms
Fire resistance ........................... 1100 degC/30 min
Water pressure resistance ......... submerged 20,000 ft
Underwater locator beacon ...... 37.5 KHz
Battery : 6yr shelf life
30 day operation
(abstracted from, NTSB - FBR & CVR, July 9, 2004 http://www.ntsb.gov/aviation/CVR_FDR.htm)
The only devices to survive a crash are the Crash-survivable memory units (CSMU's) of the flight data recorders and the cockpit voice recorders. This unit is a large centrically unit that can withstand extreme temperatures, violent crashes and tons of pressure. To provide a barrier to this unit there is a three level protection layers
� Aluminum housing - There is a thin layer of aluminum around the stack of memory cards.
� High-temperature insulation - This dry-silica material is 1 inch (2.54 cm) thick and provides high-temperature thermal protection. This is what keeps the memory boards safe during post-accident fires.
� Stainless-steel shell - The high-temperature insulation material is contained within a stainless-steel cast shell that is about 0.25 inches (0.64 cm) thick. Titanium can be used to create this outer armor as well (Gresley, 1997).
In order for a Black Box recorder to be of any use at all, the memory unit will need to withstand the impact caused by several tones of airplane free falling thousands of feet into unknown terrain. Therefore, it is quite clear that the 'box' must be well engineered to protect what is inside from impact shock, penetration and crushing as well as fire and possibly deep sea submersion. For this reason, they are very strenuously tested.
One such group which tests these 'Boxes' are Engineers at the University of Dayton Research Institute. Kevin Poorman, a mechanical engineer in the group, designs and conducts an impact shock test to monitor how a black box react under crash conditions. Manufacturers fund them to test their own new or improved black boxes. There are several ways in which the CSMU is tested. We have to remember that only the CSMU is the only thing that needs to survive a crash. Once this is saved the experts can then derive the information and proceed further with the investigation. In testing this device data is loaded in the memory boards and a series of tests are conducted. The data is then examined by the experts at the end of the tests. Some of the tests that a CSMU goes through are:
Crash Impact : Researchers shoot the CSMU down an air canon to create an impact of 3,400 Gs. (1 G is the force of earth's gravity so at 3,400 Gs the CSMU hits a honeycomb target at a force equal to 3400 times its weight. This impact is in excess than what a CSMU might face at an actual crash.
Pin drop - To test the unit's penetration resistance, researchers drop a 500-pound (227-kg) weight with a 0.25-inch steel pin protruding from the bottom onto the CSMU from a height of 10 feet (3 m). 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 C) 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 (Gresley, 1997).
The heart of a recorder is the Crash Survivable Memory Unit (CSMU). Inside it is the memory on which the data (voice or flight) is stored. In order to protect it so that it will pass the above tests, the following steps are taken when making the Black Box. The box itself is like a thick shell of amour made from stainless steel or titanium. Inside this is a layer of heat proof material which protects what's inside it from fire. Wrapped around the memory chips is another thermal material but this one is wax like and needs to be peeled off in the event of a crash to gain access to the data. The other things which make up the Black Box are the power supply and an underwater location beacon which sends out an audio signal for a month when immersed in water.
However strong they may be, black boxes do not always survive crashes and every time a recorder fails during a crash, the 'Federal Aviation Authority' will mandate new survivability requirements based on the circumstances.
Black boxes are usually sold to and installed by airplane manufacturers. Both these black boxes are installed in the tail of the plane. They are kept there as this increases they chance of survival. The precise location of the recorders depends on the individual plane. Sometimes there are even located in the ceiling of the gallery, in the aft cargo hold or in the tail cone that covers the rear end of the plane. As in an emergency an airplane nose dives towards the ground and the most impact is always felt on the front side of the airplane whereas the tail end receives the least or minimal damage than the rest of the plane ( Buck, 1994) .
Both the FDR and CVR are invaluable tools for any aircraft investigation. These are often the lone survivors of airplane accidents, and as such provide important clues to the cause that would be impossible to obtain any other way. As technology evolves, black boxes will continue to play a tremendous role in accident investigations.
Airplanes are not the only form of transportation to be equipped with black boxes. If auto insurance producers get their way, they�ll soon be harnessing this tool to reduce risk management (Barlay, 1970) .
Motorists may not know it, but their brand-new vehicle may be equipped with a black box just like those traditionally installed on aircraft. Car manufacturers now equip most new vehicles with one of these devices. Why? To gather information about seat belts, air bags and the force of impacts resulting from collisions, in a quest to build safer vehicles. These small devices may also be a boon for insurers. Black boxes contain a gold mine of information about the driving habits of motorists. In the five seconds leading up to an accident, they capture varied data such as vehicle speed, the position of the accelerator and the use of brakes; information that is worth big bucks to insurers. Some insurers believe that once this technology reaches maturity, it will let them better manage auto insurance risks. They also hope to fine-tune pricing, trim compensation for false declarations and identify drivers who are responsible for accidents. Apparently, motorists that cover on average 40,000 km per year have a much higher potential for accidents than those that drive 15,000 km or less. This device could also be used to track down cars when stolen and help the authority to get them back. High Government Officials and people who deal in sensitive nature and their jobs require them to be tracked wherever they go will find that this instrument could be the answer to all their problems ( Buck, 1994) .
ABSTRACT: This September 17, 2001 article from Automotive News cites that a panel of experts has concluded that widespread use of black boxes in cars and trucks would advance motor vehicle safety, but added that thorny questions remain about self-incrimination and privacy. (Source: Automotive News, by Harry Stoffer on September 17, 2001)
Conclusion: The Invention is the most important factor providing a tool in the hands of investigators after a disastrous and catastrophic crash. It helps in determining the causes which led to the crash. Normally there are either human or instrumental. If they are human the determination can lead to a better training for the future pilots including avoidance of fatigue due to over an excessive duty hours.
If the cause is instrumental and technical, which is very often the case, it will lead to improved designing in future aircrafts besides correcting the defects in existing fleets around the world especially of the type and make of the aircraft involved in the crash.
All around us, failure is being read; divined from the bones of the technological dead�design thus marches on. No product is ever perfect, but failure pushes us toward perfection, and every form is a compromise between the failure of yesterday and the promise of tomorrow. The human body itself is in this threshold zone: In societies not marked by endemic war or poverty, one can assume to live longer than one's forebears, but not perhaps as long as one's successors. The form keeps evolving. The human body, with its myriad sensors and indicators, its inner workings kept carefully concealed and rarely considered, may be the ultimate black box. The lesson, for either man or machine, is clear: None of us outlive our data.