Howstuffworks _How Black Boxes Work

7/26/2019 Howstuffworks _How Black Boxes Work

1/16

Howstuffworks "How Black Boxes Work"

Computer Stuff Auto Stuff Electronics Stuff Science Stuff Home Stuff Stuffo Health Stuff Money StuffTravel Stuff

People Stuff

Main> Travel> Travel Safety

Click hereto go back to the normal view!

How Black Boxes Workby Kevin Bonsor

Special thanks to L-3

Communications, Aviation

Recorders Division,for its

help with this article.

On January 31, 2000, Alaska Airlines Flight 261departed PuertoVallarta, Mexico, heading for Seattle, WA, with a short stopscheduled in San Francisco, CA. Approximately one hour and 45minutes into the flight, a problem was reported with the plane'sstabilizer trim. After a 10-minute battle to keep the plane airborne,it plunged into the Pacific Ocean off the coast of California. All 88 people onboard were killed.

http://travel.howstuffworks.com/black-box.htm/printable (1 of 16)2/4/2003 1:55:32 AM

Search HowStuffWorks and the Web
http://computer.howstuffworks.com/http://auto.howstuffworks.com/http://electronics.howstuffworks.com/http://science.howstuffworks.com/http://home.howstuffworks.com/http://stuffo.howstuffworks.com/http://health.howstuffworks.com/http://money.howstuffworks.com/http://travel.howstuffworks.com/http://people.howstuffworks.com/http://www.howstuffworks.com/index.htmhttp://travel.howstuffworks.com/http://travel.howstuffworks.com/travel-safety-channel.htmhttp://travel.howstuffworks.com/black-box.htmhttp://travel.howstuffworks.com/contact.php?s=hsw&ct=feedbackhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.l-3ar.com/http://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.l-3ar.com/http://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.l-3ar.com/http://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.l-3ar.com/http://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.l-3ar.com/http://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.l-3ar.com/http://travel.howstuffworks.com/contact.php?s=hsw&ct=feedbackhttp://travel.howstuffworks.com/black-box.htmhttp://travel.howstuffworks.com/travel-safety-channel.htmhttp://travel.howstuffworks.com/http://www.howstuffworks.com/index.htmhttp://media.fastclick.net/w/click.here?sid=4253&m=1&c=5113http://people.howstuffworks.com/http://travel.howstuffworks.com/http://money.howstuffworks.com/http://health.howstuffworks.com/http://stuffo.howstuffworks.com/http://home.howstuffworks.com/http://science.howstuffworks.com/http://electronics.howstuffworks.com/http://auto.howstuffworks.com/http://computer.howstuffworks.com/http://www.howstuffworks.com/index.htmhttp://travel.howstuffworks.com/http://travel.howstuffworks.com/


2/16


Photo courtesy U.S. Department of Defense

The cockpit voice recorder from the downed Alaska Airlines

Flight 261, held by the robotic arm of the remotely piloted

vehicle that retrieved it

With any airplane crash, there are many unanswered questions as to what brought the plane down.Investigators turn to the airplane's flight data recorder(FDR) and cockpit voice recorder(CVR),also known as "black boxes," for answers. In Flight 261, the FDR contained 48 parameters of flightdata, and the CVR recorded a little more than 30 minutes of conversation and other audible cockpitnoises.

Following any airplane accident in the United States, safety investigators from the National

Transportation Safety Board(NTSB) immediately begin searching for the aircraft's black boxes.

These recording devices, which cost between $10,000 an $15,000 each, reveal details of the eventsimmediately preceding the accident. In this article, we will look at the two types of black boxes, howthey survive crashes, and how they are retrieved and analyzed.

Recording and StorageThe Wright Brotherspioneered the use of a device to record propeller rotations, according todocuments provided by L-3 Communications. However, the widespread use of aviation recordersdidn't begin until the post-World War II era. Since then, the recording medium of black boxes has

http://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.defenselink.mil/http://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.ntsb.govhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.ntsb.govhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.ntsb.govhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.ntsb.govhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.defenselink.mil/


3/16


evolved in order to record much more information about an aircraft's operation.

Although many of the black boxes in use today use magnetic tape, which was first introduced in the1960s, airlines are moving to solid-state memory boards, which came along in the 1990s. Magnetictape works like any tape recorder. The Mylar tape is pulled across an electromagnetichead, which

leaves a bit of data on the tape.

Photo courtesy National Transportation Safety Board (NTSB)

The magnetic tape inside the flight data recorder from EgyptAir

Flight 990, which crashed on October 31, 1999

Black-box manufacturers are no longer making magnetic tape recorders as airlines begin a fulltransition to solid-state technology. Let's take a look at solid-state technology.

Solid-state TechnologySolid-state recorders are considered much more reliable than their magnetic-tape counterparts,according to Ron Crotty, a spokesperson for Honeywell, a black-box manufacturer. Solid stateuses

stacked arrays of memory chips, so they don't have moving parts. With no moving parts, there are

fewer maintenance issues and a decreased chance of something breaking during a crash.

Data from both the CVR and FDR is stored on stacked memory boardsinside the crash-survivable

http://travel.howstuffworks.com/cassette.htmhttp://travel.howstuffworks.com/electromagnet.htmhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.ntsb.govhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.flightdatarecorders.com/record.htmlhttp://travel.howstuffworks.com/computer-memory.htmhttp://travel.howstuffworks.com/computer-memory.htmhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.flightdatarecorders.com/record.htmlhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.ntsb.govhttp://travel.howstuffworks.com/electromagnet.htmhttp://travel.howstuffworks.com/cassette.htm


4/16


memory unit(CSMU). In recorders made by L-3 Communications, the CSMU is a cylindricalcompartment on the recorder. The stacked memory boards are about 1.75 inches (4.45 cm) indiameter and 1 inch (2.54 cm) tall.

The memory boards have enough digital storage space to accommodate two hours of audio data forCVRs and 25 hours of flight data for FDRs.

Airplanes are equipped with sensors that gather data. There are sensors that detect acceleration,

airspeed, altitude, flap settings, outside temperature, cabin temperature and pressure, engineperformance and more. Magnetic-tape recorders can track about 100 parameters, while solid-staterecorders can track more than 700 in larger aircraft.

All of the data collected by the airplane's sensors is sent to the flight-data acquisition unit(FDAU)at the front of the aircraft. This device often is found in the electronic equipment bayunder thecockpit. The flight-data acquisition unit is the middle manager of the entire data-recording process. Ittakes the information from the sensors and sends it on to the black boxes.

Source: L-3 Communication Aviation Recorders

Basic components and operation of an aviation recording

system

http://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.l-3ar.comhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.l-3ar.com


5/16


Both black boxes are powered by one of two power generators that draw their power from the plane's

engines. One generator is a 28-volt DC power source, and the other is a 115-volt, 400-hertz (Hz) AC

power source. These are standard aircraft power supplies, according to Frank Doran, director ofengineering for L-3 Communications Aviation Recorders.

Cockpit Voice RecordersIn almost every commercial aircraft, there are several microphonesbuilt into the cockpit to track the

conversations of the flight crew. These microphones are also designed to track any ambient noise inthe cockpit, such as switches being thrown or any knocks or thuds. There may be up to fourmicrophones in the plane's cockpit, each connected to the cockpit voice recorder (CVR).

Photo courtesy L-3 Communication Aviation Recorders

A solid-state recorder

Any sounds in the cockpit are picked up by these microphones and sent to the CVR, where therecordings are digitized and stored. There is also another device in the cockpit, called the associatedcontrol unit, that provides pre-amplification for audio going to the CVR. Here are the positions of thefour microphones:

Pilot's headset Co-pilot's headset Headset of a third crew member (if there is a third crew member)

http://travel.howstuffworks.com/turbine.htmhttp://travel.howstuffworks.com/turbine.htmhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.l-3ar.com/http://travel.howstuffworks.com/question309.htmhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.l-3ar.comhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.l-3ar.comhttp://travel.howstuffworks.com/question309.htmhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.l-3ar.com/http://travel.howstuffworks.com/turbine.htmhttp://travel.howstuffworks.com/turbine.htm


6/16


Near the center of the cockpit, where it can pick up audio alerts and other sounds

Most magnetic-tape CVRs store the last 30 minutes of sound. They use a continuous loop of tapethat completes a cycle every 30 minutes. As new material is recorded, the oldest material is replaced.CVRs that used solid-state storage can record two hours of audio. Similar to the magnetic-taperecorders, solid-state recorders also record over old material.

A Black Box Transcript

Final Words of Flight 261CVR recordings can hold important clues to the cause of an accident. In the case of Alaska AirlinesFlight 261, the conversations between the captain and his first officer pointed NTSB investigators tothe plane's stabilizer. This is an excerpt taken from the official NTSB transcript of Flight 261, whichcrashed on January 31, 2000, off the coast of California. This excerpt contains an exchange betweenCaptain Ted Thompsonand First Officer William Tanskyand the Los Angeles Route TrafficControl Center(LAX-CTR).

4:09:55 p.m. Thompson: Center, Alaska two-sixty-one. We are, uh,in a dive here, and I've lost control, vertical pitch.

4:10:33 Thompson: Yea, we got it back under control here.

4:11:43 Tansky: Whatever we did is no good. Don't do thatagain...

4:11:44 Thompson: Yea, no, it went down. It went full nosedown.

4:11:48 Tansky: Uh, it's a lot worse than it was?

4:11:50 Thompson: Yea. Yea. We're in much worse shapenow.

4:14:12 Public address: Folks, we have had a flight-controlproblem up front here, we're working on it.

4:15:19 Flight 261 to LAX-CTR: L.A., Alaska two-sixty-one.We're with you, we're at twenty-two-five [22,500 feet].We have a jammed stabilizer and we're maintainingaltitude with difficulty...

4:15:36 LAX-CTR: Alaska two-sixty-one, L.A center. Roger,um, you're cleared to Los Angeles Airport via presentposition...



7/16


4:17:09 Flight attendant: Okay, we had like a big bang backthere.

4:17:15 Thompson: I think the [stabilizer] trim is broke.

4:19:36 Extremely loud noise

4:19:43 Tansky: Mayday

4:19:54 Thompson: Okay, we are inverted, and now we gottaget it.

4:20:04 Thompson: Push, push, push...push the blue side up.Push...

4:20:14 Tansky: I'm pushing.

4:20:16 Thompson: Okay, now let's kick rudder. Left rudder,left rudder.

4:20:18 Tansky: I can't reach it.

4:20:20 Thompson: Okay. Right rudder, right rudder.

4:20:25 Thompson: Are we flying? We're flying, we're flying.

Tell 'em what we're doing.4:20:33 Tansky: Oh, yeah. Let me get...

4:20:38 Thompson: Gotta get it over again. At least upsidedown we're flying.

4:20:54 Thompson: Speedbrakes

4:20:55 Tansky: Got it.

4:20:56 Thompson: Ah, here we go.

4:20:57 End of recording

Click hereto read the full transcript (PDF) of Flight 261.

Flight Data RecordersThe flight data recorder(FDR) is designed to record the operating data from the plane's systems.There are sensors that are wired from various areas on the plane to the flight-data acquisition unit,which is wired to the FDR. When a switch is turned on or off, that operation is recorded by the FDR.

http://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.aviation-safety.net/cvr/cvr_asa261.pdfhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.aviation-safety.net/cvr/cvr_asa261.pdf


8/16


Photo courtesy National Transportation Safety Board (NTSB)

The damaged flight data recorder from EgyptAir Flight 990

In the United States, the Federal Aviation Administration(FAA) requires that commercial airlines

record a minimum of 11 to 29 parameters, depending on the size of the aircraft. Magnetic-taperecorders have the potential to record up to 100 parameters. Solid-state FDRs can record more than700 parameters. On July 17, 1997, the FAA issued a Code of Federal Regulations that requires therecording of at least 88 parameters on aircraft manufactured after August 19, 2002.

Here are a few of the parameters recorded by most FDRs:

Time Pressure altitude Airspeed Vertical acceleration Magnetic heading Control-column position Rudder-pedal position Control-wheel position Horizontal stabilizer Fuel flow

Solid-state recorders can track more parameters than magnetic tape because they allow for a faster

http://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.ntsb.govhttp://travel.howstuffworks.com/faa.htmhttp://travel.howstuffworks.com/faa.htmhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.ntsb.gov


9/16


data flow. Solid-state FDRs can store up to 25 hours of flight data. Each additional parameter that isrecorded by the FDR gives investigators one more clue about the cause of an accident.

Built to SurviveIn many airline accidents, the only devices that survive are the crash-survivable memory units(CSMUs) of the flight data recorders and cockpit voice recorders. Typically, the rest of the recorders'chassis and inner components are mangled. The CSMU is a large cylinder that bolts onto the flatportion of the recorder. This device is engineered to withstand extreme heat, violent crashes and tonsof pressure. In older magnetic-tape recorders, the CSMU is inside a rectangular box.

Source: L-3 Communication Aviation Recorders

Using three layers of materials, the CSMU in a solid-state black box insulates and protects the stackof memory boards that store the digitized information. We will talk more about the memory andelectronics in the next section. Here's a closer look at the materials that provide a barrier for the


ff k l k k
http://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.l-3ar.comhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.l-3ar.com


10/16


memory boards, starting at the innermost barrier and working our way outward:

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.

Testing a CSMUTo ensure the quality and survivability of black boxes, manufacturers thoroughly test the CSMUs.Remember, only the CSMU has to survive a crash -- if accident investigators have that, they canretrieve the information they need. In order to test the unit, engineers load data onto the memoryboards inside the CSMU. L-3 Communications uses a random pattern to put data onto every memoryboard. This pattern is reviewed on readout to determine if any of the data has been damaged bycrash impact, fires or pressure.

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 of3,400 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 itsweight. This impact force is equal to or in excess of what a recorder might experience in anactual 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 vulnerableaxis.

Static crush- For five minutes, researchers apply 5,000 pounds per square-inch (psi) of crushforce to each of the unit's six major axis points.

Fire test- Researchers place the unit into a propane-source fireball, cooking it using threeburners. The unit sits inside the fire at 2,000 degrees Fahrenheit (1,100 C) for one hour. TheFAA requires that all solid-state recorders be able to survive at least one hour at thistemperature.

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,


H ff k "H Bl k B W k"


11/16


including jet fuel, lubricants and fire-extinguisher chemicals.

During the fire test, the memory interface cablethat attaches the memory boards to the circuitboard is burned away. After the unit cools down, researchers take it apart and pull the memorymodule out. They restack the memory boards, install a new memory interface cable and attach theunit to a readout system to verify that all of the preloaded data is accounted for.

Black boxes are usually sold directly to and installed by the airplanemanufacturers. Both black boxes

are installed in the tail of the plane -- putting them in the back of the aircraft increases their chancesof survival. The precise location of the recorders depends on the individual plane. Sometimes theyare located in the ceiling of the galley, in the aft cargo hold or in the tail cone that covers the rear ofthe aircraft.

"Typically, the tail of the aircraft is the last portion of the aircraft to impact," Doran said. "The wholefront portion of the airplane provides a crush zone, which assists in the deceleration of tailcomponents, including the recorders, and enhances the likelihood that the crash-protected memoryof the recorder will survive."

After a CrashAlthough they are called "black boxes," aviation recorders are actually painted bright orange. Thisdistinct color, along with the strips of reflective tape attached to the recorders' exteriors, helpinvestigators locate the black boxes following an accident. These are especially helpful when a planelands in the water. There are two possible origins of the term "black box": Some believe it is becauseearly recorders were painted black, while others think it refers to the charring that occurs in post-accident fires.

Underwater Locator BeaconIn addition to the paint and reflective tape, black boxes are equipped with an underwater locatorbeacon(ULB). If you look at the picture of a black box, you will almost always see a small, cylindricalobject attached to one end of the device. While it doubles as a handle for carrying the black box, thiscylinder is actually a beacon.


H t ff k "H Bl k B W k"
http://travel.howstuffworks.com/airplane.htmhttp://travel.howstuffworks.com/airplane.htm


12/16


Photo courtesy L-3 Communication Aviation Recorders

A close-up of an underwater locator beacon

If a plane crashes into the water, this beacon sends out an ultrasonic pulse that cannot be heard byhuman earsbut is readily detectable by sonar and acoustical locating equipment. There is a

submergence sensoron the side of the beacon that looks like a bull's-eye. When water touches thissensor, it activates the beacon.

The beacon sends out pulses at 37.5 kilohertz (kHz) and can transmit sound as deep as 14,000 feet(4,267 m). Once the beacon begins "pinging," it pings once per second for 30 days. This beacon ispowered by a batterythat has a shelf life of six years. In rare instances, the beacon may get snapped

off during a high-impact collision.

In the United States, when investigators locate a black box it is transported to the computer labs atthe National Transportation Safety Board(NTSB). Special care is taken in transporting these devices


http://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.l-3ar.comhttp://travel.howstuffworks.com/hearing.htmhttp://travel.howstuffworks.com/battery.htmhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.ntsb.govhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.ntsb.govhttp://travel.howstuffworks.com/battery.htmhttp://travel.howstuffworks.com/hearing.htmhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.l-3ar.com


13/16

Howstuffworks How Black Boxes Work

in order to avoid any (further) damage to the recording medium. In cases of water accidents,recorders are placed in a cooler of water to keep them from drying out.

Photo courtesy U.S. Department of Defense

U.S. Navy Lieutenant Junior Grade Jason S. Hall (right) watches

as FBI Agent Duback (left) tags the cockpit voice recorder from

EgyptAir Flight 990 on November 13, 1999.

"What they are trying to do is preserve the state of the recorder until they have it in a location where itcan all be properly handled," Doran said. "By keeping the recorder in a bucket of water, usually it's a

cooler, what they are doing is just keeping it in the same environment from which it was retrieved untilit gets to a place where it can be adequately disassembled."

Retrieving InformationAfter finding the black boxes, investigators take the recorders to a lab where they can download thedata from the recorders and attempt to recreate the events of the accident. This process can takeweeks or months to complete. In the United States, black-box manufacturers supply the NTSB withthe readout systems and software needed to do a full analysis of the recorders' stored data.


http://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.defenselink.mil/http://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.defenselink.mil/


14/16


Photo courtesy L-3 Communication Aviation RecordersThis portable interface can allow investigators quick access to

the data on a black box.

If the FDR is not damaged, investigators can simply play it back on the recorder by connecting it to areadout system. With solid-state recorders, investigators can extract stored data in a matter ofminutes. Very often, recorders retrieved from wreckage are dented or burned. In these cases, thememory boards are removed, cleaned up and a new memory interface cable is installed. Then thememory board is connected to a working recorder. This recorder has special software to facilitate theretrieval of data without the possibility of overwriting any of it.

A team of experts is usually brought in to interpret the recordings stored on a CVR. This grouptypically includes a representative from the airline, a representative from the airplane manufacturer,

an NTSB transportation-safety specialist and an NTSB air-safety investigator. This group may alsoinclude a language specialist from the Federal Bureau of Investigationand, if needed, an interpreter.

This board attempts to interpret 30 minutes of words and sounds recorded by the CVR. This can be apainstaking process and may take weeks to complete.

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 beimpossible to obtain any other way. As technology evolves, black boxes will continue to play atremendous role in accident investigations.


http://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.l-3ar.comhttp://travel.howstuffworks.com/airline.htmhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.fbi.govhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.fbi.govhttp://travel.howstuffworks.com/airline.htmhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.l-3ar.com


15/16


What's in store for Black Boxes?According to L3 Communications, there are improvements on the horizon for black box technology.Reportedly, some form of cockpit video recorder will be developed. Such a recorder would be able tostore video images in solid-state memory.

Other Uses for Black Box Technology

Currently, black boxes aren't just taking flight -- they're being grounded as well. Several automobilemanufacturers are utilizing black box technology in their automobiles and a few have been doing sofor quite some time. According to an article titled "Black boxes in GM cars increasingly help police

after accidents"General Motors has been using black box technology for over a decade. The

manufacturer has been installing a Sensing and Diagnostic Module (SDM) on thousands of its cars,including the Corvette. Furthermore, this article reports that "industry insiders say as many as adozen other manufacturers install similar technology under different labels."

So, black box technology has moved from airplanes to automobiles -- where is it headed next? Itcould be on you. Right now it's just a prototype, but soon the SenseCamcould provide you with an

incredible amount of information about -- well, you!

Let's say you attended a crowded convention last month. Because you forgot your PDA, you were

forced to scribble dozens of phone numbers and emails down on random cocktail napkins. You madeplans with several colleagues, but much like the random napkins in the washing machineat home,

your memory just didn't hold up. But, all would not be lost -- if you were wearing a SenseCam.According to its manufacturer, this badge-sized wearable camera reportedly captures up to 2000VGA images within a 12-hour day and stores it in a 128Mbyte flash memory. So, most every

scribbled note and every promised meeting would be recorded for you to look at later.

For more information on black boxes and related topics, check out the links on the following page.

Lots More Information

Related HowStuffWorks Links

How Airline Crews Work

How Baggage Handling Works How Airplanes Work

How Airports Work


http://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.macon.com/mld/macon/business/industries/automotive/3649628.htmhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.macon.com/mld/macon/business/industries/automotive/3649628.htmhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://research.microsoft.com/hwsystems/http://travel.howstuffworks.com/pda.htmhttp://travel.howstuffworks.com/washing-machine.htmhttp://travel.howstuffworks.com/flash-memory.htmhttp://travel.howstuffworks.com/airline-crew.htmhttp://travel.howstuffworks.com/baggage-handling.htmhttp://travel.howstuffworks.com/airplane.htmhttp://travel.howstuffworks.com/airport.htmhttp://travel.howstuffworks.com/airport.htmhttp://travel.howstuffworks.com/airplane.htmhttp://travel.howstuffworks.com/baggage-handling.htmhttp://travel.howstuffworks.com/airline-crew.htmhttp://travel.howstuffworks.com/flash-memory.htmhttp://travel.howstuffworks.com/washing-machine.htmhttp://travel.howstuffworks.com/pda.htmhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://research.microsoft.com/hwsystems/http://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.macon.com/mld/macon/business/industries/automotive/3649628.htmhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.macon.com/mld/macon/business/industries/automotive/3649628.htm


16/16


How Airport Security Works

How Air Traffic Control Works

How Becoming An Airline Pilot Works

How Customs Works

How Airline Freight Works

How the Federal Aviation Administration Works

Other Great Links

National Transportation Safety Board

Federal Bureau of Investigation

L-3 Communications Aviation Recorders

Honeywell

Aviation Safety Network

Mechanical Engineering: And I Alone Survived

SenseCam

"Black boxes in GM cars increasingly help police after accidents"

Home Store Newsletter SearchAdvertising Privacy ContactAbout Help

1998 - 2005 HowStuffWorks, Inc.

htt //t l h t ff k /bl k b ht / i t bl (16 f 16)2/4/2003 1 55 32 AM
http://travel.howstuffworks.com/airport-security.htmhttp://travel.howstuffworks.com/air-traffic-control.htmhttp://travel.howstuffworks.com/pilot.htmhttp://travel.howstuffworks.com/customs.htmhttp://travel.howstuffworks.com/air-freight.htmhttp://travel.howstuffworks.com/faa.htmhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.ntsb.govhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.fbi.govhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.l-3ar.com/http://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.flightdatarecorders.com/record.htmlhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://aviation-safety.net/index.shtmlhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.memagazine.org/backissues/march00/features/alone/alone.htmlhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://research.microsoft.com/hwsystems/http://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.macon.com/mld/macon/business/industries/automotive/3649628.htmhttp://www.howstuffworks.com/index.htmhttps://store.howstuffworks.com/howstuffworks/hsw-sale.htm?src=footerhttp://travel.howstuffworks.com/register.htmhttp://travel.howstuffworks.com/search.htmhttp://travel.howstuffworks.com/about-hsw2.htmhttp://travel.howstuffworks.com/privacy.htmhttp://travel.howstuffworks.com/contact.htmhttp://travel.howstuffworks.com/about-hsw.htmhttp://travel.howstuffworks.com/faq.htmhttp://www.howstuffworks.com/http://www.howstuffworks.com/index.htmhttp://www.howstuffworks.com/http://travel.howstuffworks.com/rss-feeds.htmhttp://travel.howstuffworks.com/faq.htmhttp://travel.howstuffworks.com/about-hsw.htmhttp://travel.howstuffworks.com/contact.htmhttp://travel.howstuffworks.com/privacy.htmhttp://travel.howstuffworks.com/about-hsw2.htmhttp://travel.howstuffworks.com/search.htmhttp://travel.howstuffworks.com/register.htmhttps://store.howstuffworks.com/howstuffworks/hsw-sale.htm?src=footerhttp://www.howstuffworks.com/index.htmhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.macon.com/mld/macon/business/industries/automotive/3649628.htmhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://research.microsoft.com/hwsystems/http://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.memagazine.org/backissues/march00/features/alone/alone.htmlhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://aviation-safety.net/index.shtmlhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.flightdatarecorders.com/record.htmlhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.l-3ar.com/http://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.fbi.govhttp://travel.howstuffworks.com/framed.htm?parent=black-box.htm&url=http://www.ntsb.govhttp://travel.howstuffworks.com/faa.htmhttp://travel.howstuffworks.com/air-freight.htmhttp://travel.howstuffworks.com/customs.htmhttp://travel.howstuffworks.com/pilot.htmhttp://travel.howstuffworks.com/air-traffic-control.htmhttp://travel.howstuffworks.com/airport-security.htm

Documents

Howstuffworks _How Black Boxes Work