Mystery Air Crash Black Box Found Sans Memory Part 205
coondoggie writes "The ongoing undersea search of the Air France Flight 447 wreckage had yielded one of the key items investigators were looking for this week: the flight data recorder. Unfortunately, their hopes for more information about the crash were set back, as the robot subs scouring the ocean floor retrieved the box only to find its memory part missing."
Re:Memory Part? (Score:5, Informative)
There is a technical term for it, but basically it's the actual box on the recorder chasis which stores the data; I'm not sure whether it's magnetic storage or flash memory in this case.
And separation is certainly not unknown, there was a crash a few years back where it also separated and was later found. Odds are this one will be too, but that could take some time if it's buried under other debris.
Re:Memory Part? (Score:5, Informative)
From the article, it sounds like the flight data recorder has basically been smashed to pieces. This is usually what happens to them; they're really only useful in relatively low-speed accidents.
That's not the case at all. FDRs commonly survive catastrophic high speed accidents. For example, USAir 427 in 1994 crashed in a near vertical nose-down attitude, and pretty much all that was left of that accident was small bits and pieces. The FDR was recovered and was usable. They rolled and went nose down from 6,000 feet, and the last data on the recorder indicated an airspeed of 261 knots (300 mph, or about 135 meters per second), at a 80 nose-down attitude, virtually straight into the ground. If an FDR can survive that, it can survive damn near anything.
Re:Because (Score:4, Informative)
This post provides some interesting information:
http://www.airliners.net/aviation-forums/general_aviation/read.main/5129859/1/#2 [airliners.net]
Re:Memory Part? (Score:4, Informative)
Not sure if this is relevant but I once worked on a recording device for FA/18s. The module which stores the data plugs into a slot in the aircraft or an external reader. It is approximately 80*80*30mm and grooved so it can only slide into its slot one way. On the 30*80mm side which sits flush with the surface of the reader there is a hinged lever and a locking catch. To insert the cartridge you push it say 60mm into the slot, then engage the lever with a bar on the reader surface and use leverage to push it the rest of the way. On the opposite side of the cartridge from the lever there is a 25 pin D plug which mates with a socket on the reader (or aircraft). The recording mechanism is hidden though at the time I did this work it must have been streaming tape like a TK50.
I could imagine a cartridge like this popping out of the box which writes the data to it on impact. The cartridge is extremely robust and will be probably sitting on the bottom around there somewhere. Of course the system on the airbus could be totally different from the one I saw.
Re:Memory Part? (Score:4, Informative)
From: http://www51.honeywell.com/aero/common/documents/Flight_Data_Recorder_(SSFDR).pdf [honeywell.com]
The SSFDR's crash survivable memory unit (CSMU) provides for complete data recovery when subjected
to the crash conditions stipulated in ED-55 and ED-56a:
Impact Shock 3400G, 6.5 milliseconds
Penetration Resistance 500 lb. weight from 10 feet
Static Crush 5000 lbs., 5 minutes
High Temperature Fire 1100C, 30 minutes
Low Temperature Fire 260C, 10 hours (per ED-56a)
Deep Sea Pressure and Sea Water/Fluids Immersion 20,000 feet, 30 days