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.
I am a little surprised there isn’t a catastrophic “save last 5 minutes” type thing like with a dashcam. I guess in many cases that last 5 minutes would have been saved by the fact that it crashed, but the issue was overlooked for planes that suffer a major event and stay in the air.
In this case, I seriously doubt the pilots’ conversation is going to add much to the investigation. It seems pretty obvious what happened and outside the pilots’ control.
My cheap dashcam does rolling saves if days worth of HD video… but aviation safety can only manage 2 hours of audio? Weeks worth of buffer should be trivial to add from both an economic and operational standpoint, and would have solved this issue (though not the door, obviously).
The logs should be getting pushed to a meaningful amount of local storage, and radio chatter saved centrally (there’s almost certainly amateurs stockpiling these recordings - large institutions are definitely capable).
Better yet, upload the info regularly. Remember MH370, where we only know roughly what happened because it occasionally checked in with satellites? So the capability exists.
Oh - we absolutely should be doing that, particularly when the passengers can use the Internet on flights already - but that seems like a (entirely reasonable) heavier lift, compared to a trivial storage upgrade and/or a minor config change to match euro standards or better.
As far as I know, there’s telemetry from the whole plain, not only the voice recording, so there might have been something useful ¯\_(ツ)_/¯
Edit: but just after responding I found out that the rest of the data is intact, so I was wrong
Yeah, I might have been unclear, I knew that other telemetry was available and it was just the voice recordings that were wiped due to the time they operated after the incident.
Telemetry is going to be numerical data that likely compresses very well, so even with a large amount of sensors I can’t imagine it taking that much.
And yeah, voice users significantly less than video, where modern cheap dash cams can record days on a small SD card. Methinks flight recorders can do better. At the least they should be viable for the max flight time of the aircraft.