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CVR recording time

Plague

Well-known member
From so many accident, and more particularly incident, reports it seems that CVRs almost universally have a 2 hour capacity. This is generally fine for accidents, but again and again I read that much or all of the recordings of incidents is lost because the recorder wasn't turned off at the end of the flight as it should be in such cases. Since this action is usually the responsibility of the pilots then there is obviously going to be a temptation to 'forget' to do so if they think it might sound a bad note on them.

So I have two questions:
Why is there not some automated or remote way to save the recordings? Alternatively all files could be backed up in real time to a hard drive outside the box. That could easily hold hundreds of hours and wouldn't need to be crash proof as the two hours in the box should usually be enough for a disaster.

Why is the requirement still only 2 hours? It's nearly 20 years since it was enacted and storage has moved on considerably. Surely double or triple that should be easily achievable.
 

MsHighAltitude

Administrator
Staff member
For the second question, probably because the device will have to be re-certified and nobody has any incentive to do that? Well, the NTSB maybe, but they aren’t the ones calling the shots.
 

Plague

Well-known member
Well, the NTSB maybe, but they aren’t the ones calling the shots.
They are ICAO recommendations, but as such it's presumably down to individual countries' aviation authorities to require them.
Even so, ICAO updating/upgrading the recommendations would be a step.
 

affinity4aviation

Active member
From so many accident, and more particularly incident reports, it seems that CVRs almost universally have a 2 hour capacity. This is generally fine for accidents, but again and again I read that much or all of the recordings of incidents is lost because the recorder wasn't turned off at the end of the flight as it should be in such cases. Since this action is usually the responsibility of the pilots then there is obviously going to be a temptation to 'forget' to do so if they think it might sound a bad note on them.

So I have two questions:
Why is there not some automated or remote way to save the recordings? Alternatively all files could be backed up in real time to a hard drive outside the box. That could easily hold hundreds of hours and wouldn't need to be crash proof as the two hours in the box should usually be enough for a disaster.

Why is the requirement still only 2 hours? It's nearly 20 years since it was enacted and storage has moved on considerably. Surely double or triple that should be easily achievable.
Excellent questions. There would be fewer accidents if they knew what the contributing factors were, rather than have a CVR that doesn't have the entire scenario recorded. I've seen this on 'Air Disasters.' Most things boil down to money and time. Helping prevent future accidents is a worthwhile investment and a longer CVR recording time sounds reasonable and wise. .
 
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Zeede

Administrator
Staff member
because the recorder wasn't turned off at the end of the flight as it should be in such cases. Since this action is usually the responsibility of the pilots then there is obviously going to be a temptation to 'forget' to do so if they think it might sound a bad note on them.
Pilots don't manually arm or disarm or "turn off" the CVR and FDR for each flight. If the plane is powered up, the recording starts. Powered off, recording stops.

I agree that the capacity should usually be longer, but generally when a flight goes awry, it happens in the last few minutes.

There have also been cases where the black boxes weren't working correctly, but I can't recall a single case where the black boxes kept recording after the crash. (Crash = power loss = no more black box recording) Do you have a specific incident in mind?
 

Roichi

Active member
The 2 hours imit is a requirement by the pilots union in the USA. They don't want longer recording times.
And yeah, I can get why, when you look at how personal data is handled in the US in general. It is a different story in Europe.
But as the devices have to be ready to use in the US the recording time is set there.

Permanent readout would not be possible with the currently installed recorders. There is no out channel. For readout the recorder has to be removed and connected to a workbench with specialized software. So you would need to upgrade existing devices and recertify them together with the rest of the storage system.
 

Plague

Well-known member
Pilots don't manually arm or disarm or "turn off" the CVR and FDR for each flight.
Yes, I understand that, but I thought there are times when their SOPs require them to pull the breaker after landing. There have been cases where this wasn't done, and in some of those it appears to have been a deliberate (in)action.
It's human nature obviously, but that's why you need to allow for it.

Do you have a specific incident in mind?
Of a recorder continuing to run after a crash, no. Even if the plane was largely intact it would likely be promptly shut down anyway.
It's the incidents, where the plane is undamaged or not badly damaged that are the problem, not actual crashes. There is always learning available from incidents to avoid them becoming accidents in future, so the loss of data, for whatever reason, is based for air safety.
 

Plague

Well-known member
I've been sent a link to this article from 2018:
A Boost for CVRs

Apparently "The European Union (EU) already has ordered that new large commercial aircraft be equipped with 25-hour CVRs beginning on Jan. 1, 2021, and the International Civil Aviation Organization (ICAO) has adopted a 25-hour standard, also effective Jan. 1, 2021, for commercial transport aircraft with a maximum certificated takeoff mass of more than 27,000 kg (59,524 lb)"

The NTSB are asking for similar but also for it to apply to existing aircraft eventually:
"The NTSB’s safety recommendation letter did not specify an effective date for its recommended action but noted that ICAO and the EU have specified 2021. In addition to that requirement for newly manufactured airplanes, the NTSB called for a Jan. 1, 2024, deadline for applying the 25-hour requirement to existing airplanes that are required to carry a CVR."

My search the other day didn't turn up anything about this - weird.

So it looks like it is already happening, though maybe not yet in the US.
 

affinity4aviation

Active member
I've been sent a link to this article from 2018:
A Boost for CVRs

Apparently "The European Union (EU) already has ordered that new large commercial aircraft be equipped with 25-hour CVRs beginning on Jan. 1, 2021, and the International Civil Aviation Organization (ICAO) has adopted a 25-hour standard, also effective Jan. 1, 2021, for commercial transport aircraft with a maximum certificated takeoff mass of more than 27,000 kg (59,524 lb)"

The NTSB are asking for similar but also for it to apply to existing aircraft eventually:
"The NTSB’s safety recommendation letter did not specify an effective date for its recommended action but noted that ICAO and the EU have specified 2021. In addition to that requirement for newly manufactured airplanes, the NTSB called for a Jan. 1, 2024, deadline for applying the 25-hour requirement to existing airplanes that are required to carry a CVR."

My search the other day didn't turn up anything about this - weird.

So it looks like it is already happening, though maybe not yet in the US.
"A Boost for CVR's" was interesting and proved several of your points.
Most accidents occur either in the first 3 minutes or in the last 10 minutes, due to the plane being close to the ground and operating at less than full speed. There is far less time and space to recover from a mistake, a mechanical issue or from weather conditions, etc. per the research I read.
 
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