Black Box question!!?

Question

After watching several Air Crash Investigation programs I have noticed that the flight and voice recorders even when referring to recent incidents, these boxes always record the data onto tape (magnetic media). Often this tape is torn once these boxes are retrieved.

Why don't these boxes record data digitally? They might be able to record more then just the last 30 minutes worth too...

Answer 1

yeah, they won't change anything unless made to, especially if it uses money and doesn't procure them anything.

digitally is much more easily wiped out. Apart from shocks, a short circuit, and any electric problem would wipe out the data. on the tape style, it would only stop. whatever data would be preserved.

it could also be more easily faked or altered during the flight and after the crash, during the investigation. digital means it would has less ground in court. A good lawyer can disprove everything but he can't convince the judge that something unalterable without visible damage in front of him doesn't exist. (there are digital FDR though)

30 minutes was thought to be enough. When it wasn't it was usually because the flight kept on going and landed safely in which case there were people to interrogate. .Course, sometimes, the incident occurs then the flight crashes like an hour after, but usually, if that was the case, the pilots would have communicated the problem to ATC. so 30 minutes is okay 99% of the time

Answer 2

As many have said it takes a long time and alot of money to make those kinds of changes with the FAA (government). Nobody in the FAA wants to be responsible for anything anymore and someone is going to have to approve those changes.  

Answer 3

Digitally can break upon an impact.

Answer 4

As an aside and addition...

I understand there's something new out there too, I haven't heard about it in regards to an actual crash investigation, but I've heard about it around the simulators.

Apparently, some of the new black boxes have a memory stick in them. Just after the crash, the investigators can take the stick, pop it into a simulator and actually "ride" the crash.

I don't have time to look for the reference now, but I've heard about it enough that I'm reasonably sure it's true.

Answer 5

airline companies don't change  things that will cost them money.

unless they have to, or it will make them money.

Answer 6

Although many of the Cockpit Voice Recorders,Flight Data Recorders aka

"Black boxes" in use today use magnetic tape, which was first introduced in the 1960s, airlines are moving to solid-state memory boards, which came along in the 1990s. Magnetic tape works like any tape recorder. The Mylar tape is pulled across an electromagnetic head, which leaves a bit of data on the tape.

"Black-box" manufacturers are no longer making magnetic tape recorders as airlines begin a full transition to solid-state technology

Solid-state recorders are considered much more reliable than their magnetic-tape counterparts. Solid state uses 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 boards inside the crash-survivable memory unit (CSMU). In recorders made by L-3 Communications, the CSMU is a cylindrical compartment on the recorder. The stacked memory boards are about 1.75 inches (4.45 cm) in diameter and 1 inch (2.54 cm) tall.

The memory boards have enough digital storage space to accommodate two hours of audio data for CVRs 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, engine performance and more. Magnetic-tape recorders can track about 100 parameters, while solid-state recorders can track more than 700 in larger aircraft.  

Answer 7

because if a battery dies its so long info...

Answer 8

The most recent flight data recorder models are fully digital, recording data on chips, and their capacity can be as large as 60 hours worth of data (if mot more), although 60 hours is due to numerical compression (like on the F-1000 and F2100 units from L3), without compession similar units would be restricted to around 25 hours of data, which is still quite a bit. The so called SSFDR (solid state flight data recorder) are however not retrofitted in existing aircraft already using older model, unless the units already on board have failed and requires replacing.

Very rarely would an accident investigation need more than just a few minutes to have a good idea what happened -- although there are cases where the origin of the problem goes back to even the previous flights. But FDR are a good source of information for things like fleet monitoring, seeing for instance an engine progressively getting hotter and thirstier, indicating that it may be due for some maintenance work. But because FDR are usually not very easily accessible, the fleet monitoring aspect is tasked to new quick access recorder, which despite not being crash worthy like the FDR's are, can have immense capacity. Some even have wireless remote download options.

Answer 9

The circuitboards needed to make a digital recording device would definitely shatter upon impact.  Plus, it's usually the last 30 minutes that tell what happened - before that normally doesn't matter.  (By the way, I love that show...)