Alaska 737 cockpit voice recorder data erasure renews industry safety debate
The cockpit voice recorder data on the Alaska Airlines Boeing 737 MAX 9 jet which lost a panel mid-flight on Friday was overwritten, U.S. authorities said, renewing attention on an industry call for longer in-flight recordings.
National Transportation Safety Board (NTSB) chair Jennifer Homendy said on Sunday no data was available on the cockpit voice recorder because it was not retrieved within two hours - when recording restarts, erasing previous data.
The U.S. requires cockpit voice recorders to log two hours of data versus 25 hours in Europe for planes made after 2021.
The International Civil Aviation Organization (ICAO) has since 2016 called for 25-hour recording on planes manufactured from 2021.
"There was a lot going on, on the flight deck and on the plane. It's a very chaotic event. The circuit breaker for the CVR (cockpit voice recorder) was not pulled. The maintenance team went out to get it, but it was right at about the two-hour mark," Homendy said.
The NTSB has been vocal in calling for the U.S. to extend its rule to 25 hours. The U.S. Federal Aviation Administration (FAA) a month ago said it was proposing to extend to 25 hours – but only for new aircraft.
Why the fuck would they have only hours of recording? Even my cheap voice recorder can go for hundreds of hours
An example of a corporation doing the bare minimum required by law.
Laws which they've lobbied and used regulatory capture to slow any updates.
Regulations are important.
These regulations were written a long time ago when physical tape was used. Boeing has since captured the American regulatory system.
It's an example of engineers being handed a requirement and meeting it.
No. If an engineer were to design this system today, it'd have hundreds of hours of recording.
This is either a mandate from management, a relic from old systems that haven't been updated, or a combination.
The FAA reqs are the relic. You don't just get to go nuts and add whatever you want to a product - especially on airplanes. They were given the requirements and met them.
I'm sure the FAA reqs specify a minimum.
Yeah, that's my point. The minimum is 2 hours. We deal with a lot of minimums and the culture doesn't really involve going past requirements. This is something you probably buy, rather than make in house (though I may be mistaken), so you're just going to find the one that meets minimum specs.
Huh. What do I think? Let me tell you what I think, Stan. If you want Boeing to have 25 hours of audio like your pretty boy EASA over there, then why don't you just make the minimum 25 hours of audio?
I agree. In fact it should probably be 240 hours of audio. I was simply refuting the slander on random engineers, as though they're the ones who made the choice of only two hours.
To be entirely fair your cheap voice recorder is not expected to also survive a plane crash. That being said European planes have more without issue so yeah.
2-3 large NVMe drives, mirrored to each other and properly encased, would provide years worth of recordings and survive a crash. They save so little because they want to.
Ah, yes, why didn't the aviation engineers of the entire world think of that? Such a simple solution to a complex problem!
They probably did. There's a reason that businesses set retention policies on emails stating that everything gets deleted after a certain amount of time, regardless of space. They don't want the record to exist to be found during the discovery phase of a lawsuit.
That and, more practically, after a certain amount of time you just don't need the papers. The world generates so much data and most of it anymore is unnecessary, redundant, or obsolete within a few months of generation. It absolutely makes sense to retain data for five or ten years, but after that... At what point is it just hoarding stuff no one will ever look at?
They literally did. The ICAO adopted the 25 hour standard in 2016, dumbass.
They probably still use physical tape.
Modern DVDR (digital voice data recorder) use nvme storage now. Tape is still in use on old planes, but I would suspect this brand new max has the newer versions.
We just have another person sit in the cockpit and write down everything that happens around them. Don't need to worry about pulling the breaker that way.
Plausible deniability.
Oopsie whoopsie. Looks like I deleted the evidence against me and I'll go free now...
In this situation the pilots are absolutely not at fault. You’re assertion fails all know evidence so far.
Nobody blamed the pilots, but Boing tho !
The pilots do oppose having 25 hrs of recordings tho, under privacy concerns. Source
Whether that's a valid concern or not is another question entirely.
It makes a little sense but personally I believe EVERYTHING that happens in the cockpit could be very important details, if the pilots want privacy there are other places in the plane. Autopilot does most ofnthe job letting them take brakes etc... Of course I am no pilot and haven't even been on a plane so my point is not very valuable.
I'm not sure I want the pilots to leave the cockpit so they can have a conversation they don't want to have recorded... "If you're here, who's flying the plane?"
This isn't entirely an excuse, but a CVR has some pretty serious durability requirements. They're required to withstand physical forces, sustained exposure to direct flame, lengthy submersion in sea water...it's not a trivial device.
How much could a banana cost, Michael? 10 bucks?
Here's some money, go see a Star War
On top of all that, you have to factor in the development and testing costs for the CVR or FDR too. These are usually off the shelf, previously developed components. A seemingly trivial change like bigger storage suddenly costs several hundred thousand dollars to retest and time to recertify by dozens with agencies around the world. If the regulations have not changed, then there is no reason for to go through that whole R&D process again when the same bought and paid for system works.
....which you'd think has all already been done, since Europe pretty much uses the same airplanes as the US, so compatible equipment ought to exist.
You have to recertify the component on each aircraft you install it on. If the manufacturer doesn't have a reason to update a component they won't recertify it.
To be fair, your voice recorder probably can't withstand being slammed into the ground at 500mph...:P
Only marginally related, but I run into this a lot with "Why can't I have more space in my homedir? I can go buy a disk from BestBuy and it's only $50." The two products - a TEAM disk from BB and the media approved for enterprise (let alone emergency/recovery) work are from two different worlds.
Probably when these regulations were put in place in the 1960s or whenever, there were technical limitations on these recording devices.
Yeah that’s pretty goddamned short. If you can only record two hours you’d better not have flights longer than that.
Flight recorders have a very long history with modern ones being engineered in the 1960s. They used film and magnetic tape loops, having very limited capacity. That's where we get 2 hours from. Early ones only ran for 30 minutes, so 2 hours is pretty good in comparison.
It's time to upgrade the regulations to match our current technology instead of 1990s limitations.
Modern ones are solid state and the owner can choose how long they want to record for. Most ETOPS aircraft will record for much longer than 2 hours. I believe my airline records for 25 hours, even though our aircraft are not based in Europe.
Absolutely. My comment is about why a regulation would be 2 hours when today we can get more capable, air rated parts. US regulation is lagging behind, but it was based on what was within reach 20+ years ago. Heck, I bet most craft would eventually become 25 hours voice recording as older standard recorders become no longer available.