Example: Lemmy Federated Airlines Flight 360 crashes with no survivors. Now the Lemmy Federation Air Crash Investigation Bureau finds the Flight Data Recorder and Cockpit voice recorder, and they take those boxes aboard Lemmy Investigation Bureau Airfleet Flight 180 back to the investigation headquarters for analysis. This flight also crashes with no survivors. What happens now? Will the black boxes of Flight 360 still be readable? Also, what were the odds of this scenario happening?
Sorry I couldn’t sleep and had to get this question out of my head.
According to the National Safety Council there are “too few deaths to calculate odds”. (source). So, I’m pretty sure we can call the probability of two extremely-rare events happening independently in succession as near to nothing as makes no odds.
Also, modern combined units (sometimes called CVDRs) are built to withstand multiple impacts, and their storage medium is solid state. It is highly likely that, in the event of this near-impossible scenario, the recorder could be recovered again.
Cockpit voice recorders are designed to survive catastrophic plane crashes. They are incredibly durable.
This isn’t due to airbags or crumple zones, or anything that would be used up in the first crash. If it can survive the first crash it will survive the second.
I am not an expert, but I don’t think there’s a “good for one crash” stamp or anything on the recorders, so I’d imagine that since they’re made as indestructible as possible, they could survive multiple plane crashes
What do you mean “what happens”?
Either the CVR and FDR survive or they don’t and the final report is written without them. Neither are indestructible and they fail or are unrecoverable in a fraction of cases.
Yes, a piece of hand luggage designed to survive a plane crash will survive a plane crash.
Yes but they never designed it to crash a second time. 🤣
Kinda like how many times can you send a sub to the bottom of the ocean before it doesn’t return?
Depends on whether it was made with carbon composites against all understanding of safe compression cycling.
Good point - if it was lost underwater it might have used up the sonar pinger battery and would be harder to find if lost underwater a second time.
This is not an answer but rather a follow up question, once I read* that black boxes expired. Is that period meant to be years? Months? Do they actually expire or just actually rust due to (in ocean related events) the water?
- Edit: appreciate the answers. TIL.
Trained air mishap investigator here (finally get to say that)! The “expiration” is mainly the batteries for the sonar ping in the event of a water recovery. Beyond that, over the timeframe of years corrosion and slow water intrusion can degrade the stored data. On older systems the magnetic tape had a much shorter life before data is lost but on the new solid state ones it is less likely, but still not impervious to time. For Air France 447 they were recovered 2 years after the accident and the data was still viable. There is definitely a time period beyond which data will eventually be lost, but we dont have an exact number for it and it is based on variables such as the exact forces at impact, water depth and dozens of other unknown factors. MH370 for example has only been underwater for 9 years and I would expect much, if not all the data from its boxes to be recoverable at this time. If it goes another 10-15 then we really don’t know but it’s likely something would be on the solid state drives. As MH370 shows the pinger battery is the main time limit because once it’s done the odds of finding the wreckage goes down dramatically.
Awesome! You could start a community! When did black boxes begin? What was the original recording media? What all info is stored? I could search these things, but it’s much cooler to learn it from someone who has real experience!
They began around WWII with a few different countries working on them independently. The early standard was magnetic wire, essentially the same technology as tape but since it’s a metal wire it was stronger against impact. As tape and shielding got better they switched to tapes because they work better with higher capacity and fidelity. They took off and became widespread/mandatory during the jet age after the war and started switching to solid state around the 90s with most being converted by now.
Not sure there is enough content for its own community but I did start c/flying, but it’s not very active yet. On reddit there was a user, u/Admiral_Cloudberg who made amazing writeups on various mishaps. If we could get him to come over to lemmy it would be a great start.
Please, make a recommendation for a community name, I’ll admin it, I could read about this for hours!
Thank you! Super interesting.
Um… Air france was found after 2 years. Did you misremember or mistype?
Yeah, mistype. Thanks for the backup.
Really informative, thanks!
Interesting, thank you!
