CVR of crashed 737 Sriwijaya Air SJ182 recovered ... in pieces - Page 1
Forum section: electronics / general

author: BravoV
author_rank: Super Contributor
timestamp: January 15, 2021, 12:13:37 pm
content: These are the cockpit voice recorder recovered in pieces from the recent 737 plane crash Sriwijaya Air SJ182, while the FDR was recovered 1st still looks fine physically.Assuming the soldered memory chips are still there, I guess its very challenging to recover the recorded cockpit voice with this condition.

author: fcb
author_rank: Super Contributor
timestamp: January 15, 2021, 12:45:09 pm
content: Not shown is the memory module for the CVR - seperate and housed in a smaller, thicker, fireproof block ontop of this.The mangled mess shown is the PSU, interface, control logic etc.. not the important bit.

author: BravoV
author_rank: Super Contributor
timestamp: January 15, 2021, 01:23:34 pm
content: That is good to know, hope they will find that memory block soon.I guess the beeping signal part is destroyed in that mess ?

author: fcb
author_rank: Super Contributor
timestamp: January 15, 2021, 03:35:20 pm
content: Quote from: BravoV on January 15, 2021, 01:23:34 pmThe locator beacon (which works for 30 days), is typically attached to the memory block, and is also hardened.CVR and FDR are located in the rear of the plane - I'm not sure I've seen pictures of one as badly damaged as the OP posting, must have hit the ocean very hard.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: January 15, 2021, 03:57:15 pm
content: here's an example of the memory module in a solid-state flight recorder :https://youtu.be/a-y2YoMduYo?t=684

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 16, 2021, 02:37:32 am
content: Given how cheap Flash memory is nowadays, why not effectively RAID 1 the two units so recovering just one gets all the data?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: January 16, 2021, 11:04:55 am
content: Quote from: NiHaoMike on January 16, 2021, 02:37:32 amAviation gear has development & approval times of many years and lifetimes of decades, so "nowadays" won't be flying for quite a long time

author: amyk
author_rank: Super Contributor
timestamp: January 16, 2021, 09:21:36 pm
content: Commodity NAND flash is horrible from a reliability standpoint.The equipment flying today might be using NOR, and already mirroring them with error correction.

author: tom66
author_rank: Super Contributor
timestamp: January 16, 2021, 09:52:08 pm
content: The DiskOnChip 2000 product in the flight recorder that Mike tore down is NAND flash.Provided you have sufficient error correction and don't exceed the write endurance, it should be fine for its application.I wonder what the thermal stickers are used for, on Mike's unit, if the 224 degree sticker is activated for instance, does that indicate to the engineers that the data might require alternative recovery methods (perhaps powering it up normally could cause permanent damage as the silicon has been 'cooked' and care needs to be taken to extract data?)

author: urbis
author_rank: Unknown
timestamp: January 18, 2021, 06:47:45 pm
content: I would imagine so.I’m surprised more real time data and voice isn’t streamed via satellite in this day and age.We all saw what happened with MH370 and the level of data that COULD have been obtained with a subscription.

author: aqarwaen
author_rank: Regular Contributor
timestamp: January 18, 2021, 09:09:55 pm
content: even if flash memory is damaged,should it be not be possible to recover data directly from dies or atleast partialy,if u have enough money?

author: Halcyon
author_rank: Unknown
timestamp: January 24, 2021, 07:40:13 am
content: I've actually had some involvement in recovering data from an aircraft crash. Flight voice/data recorders are designed so that even if the controller and electronics that operate the device are broken or involved in a fire, the actual recording medium is designed to be removed on its own and read back. It just depends on the device.Quote from: aqarwaen on January 18, 2021, 09:09:55 pmYep, this is the way I've done it before (and it's not super expensive to do). My latest job was reading out the flash from an older iPhone. Managed to get a 50% read which still resulted in some usable data. The other half of the chip was buggered.

author: station240
author_rank: Unknown
timestamp: January 24, 2021, 10:46:14 am
content: Quote from: fcb on January 15, 2021, 03:35:20 pmLast transponder transmission from 75ft above the water, was 358knots (660km/hr).I feed that speed into a crash test calculator (for car crashes), ended up with 5,000GAn undamaged CVR looks like this:The Oil filter sized can is the memory module, attached to the right of it is the tube containing the locator beacon.It's possible for the beacon to be broken free, making the memory module harder to find.The two destroyed PCBs posted earlier, are in the top and bottom halves of the thin box at the base.

author: tooki
author_rank: Super Contributor
timestamp: January 24, 2021, 03:52:11 pm
content: Quote from: BravoV on January 15, 2021, 12:13:37 pmIf that’s what the unhardened parts look like, I’d guess the chances of data recovery from the actual memory module are very, very high.

author: tooki
author_rank: Super Contributor
timestamp: January 24, 2021, 04:03:00 pm
content: Quote from: urbis on January 18, 2021, 06:47:45 pmAs already said, the aviation industry is very, very slow to adopt new things. But this has been in testing for years, and CVR/FDR manufacturers are indeed now offering black boxes with satellite links. (As well as the 25h recording time required for new black boxes by one of the aviation regulators.)Bear in mind that many airlines already use flight deck systems with satellite links, as seen in various recent non-crashy incidents where airline technical ops could monitor the flight systems in real time.

author: coppercone2
author_rank: Super Contributor
timestamp: January 24, 2021, 11:13:28 pm
content: would all this stuff really help or just make them focus on generally finding 1 cut corner and ignoring the ones that seem to hold vs generally improving hopefully everything. right now do you even want to tell them exactly what it was (letting cheap skates play whack a mole) or to fix all the problems?? IMO its the wrong direction to take.Its like saying 'oh dont worry about this piece of shit generator we have thats obviously going to explode and catch on fire, charlie is watching it now, so we can figure out the cheapest way to make it not explode next time it explodes'. IMO this monitoring is a false sense of security.The last thing I want to hear is garbage being put into the air because they convinced someone they can analyze it better when it crashes again. chances are its related to god damn obvious design problems like they have been finding for how long now?This is like a ATM camera protecting someone from a fucking bear attack. The hope is there is a bear that loiters, but usually its a black swan that won't have a useful signature. or that signature will get covered up by... shitty management. Those cracks, vibration, signal resets, buzzes and things are just normal harmless glitches!!

author: Halcyon
author_rank: Unknown
timestamp: January 24, 2021, 11:25:00 pm
content: I'm surprised they haven't invented a better mechanism for recovery of recorders. Maybe have a secondary backup recorded that jettisons itself right before or the moment of impact, then it can just be fished out of the water or whatever. At least that way you have a lot of the valuable data, even if you miss the last few seconds, I think by that stage, the data is less important anyway.

author: james_s
author_rank: Super Contributor
timestamp: January 24, 2021, 11:49:20 pm
content: I think it would be very difficult to detect the proper moment to jettison, and the recorder would still be traveling at the same speed as the aircraft so it might not do much good. It would pop out and smash into the earth at the same speed without the possible benefit of the fuselage absorbing some of the impact.

author: amyk
author_rank: Super Contributor
timestamp: January 25, 2021, 12:01:20 am
content: Quote from: james_s on January 24, 2021, 11:49:20 pm...and considering that it is located in the tail, which is the last part to hit anything, I suppose everything in the nose ends up looking like it went through the Hydraulic Press Channel...

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: January 25, 2021, 12:58:16 am
content: Quote from: Halcyon on January 24, 2021, 11:25:00 pmAs someone who hangs around aviators and is a plane nerd, we see this all the time. I've seen sketches that depict aircraft with essentially ejector seats, whole detachable in-flight fuselages with parachutes, etc.The problem is that is complicates things and doesn't solve the sinister root cause. If someone onboard has it in for the aircraft and it's souls...The thing about transponders is the destructive party finds a way to disable the device.

author: pickle9000
author_rank: Super Contributor
timestamp: January 25, 2021, 01:02:26 am
content: There is talk of making a duplicate of the information and storing it on the outside of the aircraft and allowing it to be knocked off in a crash. It would have a gps and the ability to float. The purpose would be to locate the aircraft / survivors and have a backup or the boxes.

author: james_s
author_rank: Super Contributor
timestamp: January 25, 2021, 04:40:43 am
content: Quote from: amyk on January 25, 2021, 12:01:20 amAt the speeds catastrophic crashes occur at, the fuselage and most of its contents essentially shatters into tiny fragments. It tends to stir up the conspiracy theorists who lack a sufficient understanding of physics to understand why they don't see recognizable aircraft wreckage after a nose in crash. The only parts that tend to survive those crashes relatively intact are the really solid heavy stuff like landing gear struts and the shafts from the engine cores, and hopefully the recorders.

author: tooki
author_rank: Super Contributor
timestamp: January 25, 2021, 11:15:42 am
content: Quote from: Halcyon on January 24, 2021, 11:25:00 pmIn fact, this has been considered for commercial aircraft for a long time, and apparently has been standard equipment in US Air Force aircraft since 1993, so it’s a proven technology. It’s just not cheap.Quote from: james_s on January 24, 2021, 11:49:20 pmEvidently not a problem, since the military has been using this technology for decades.

author: fcb
author_rank: Super Contributor
timestamp: January 25, 2021, 11:23:28 am
content: FDR/CVR survival will increasingly be irrelevant. Old planes with old FDR/CVR will get rotated out of the fleet far quicker than improvements will be mandated.Alot of planes now lease turbofan engines and pay for "Power-By-The-Hour", this is enabled by pretty sophisticated real-time data beamed to satellites. Data costs tend towards zero - the amount of data collected in realtime will easily exceed that stored by standard black-boxes. You could see a point where crash investigation results and subsequent groundings could occur within seconds of a crash. Juan Browne will be able to release videos within minutes.Presumably airlines/manufacturers will use this data to further reduce maintainence hours and costs without compromising safety.

author: sixtimesseven
author_rank: Frequent Contributor
timestamp: January 25, 2021, 12:08:25 pm
content: Quote from: Halcyon on January 24, 2021, 11:25:00 pmSorry. Did not see the last postThe tech to downlink the data via satelite is installed in every new plane. However, because of costs, carrier usually reduce the update rate to the lowest possible setting. One more thing starlink and cheap satelite access will hopefully change in the future.