Malaysia Airlines Plane "Loses Contact"
Discussion
Leptons said:
hidetheelephants said:
There's no chance of that, FDRs have survived far more violent crashes and being incinerated. Whether prolonged immersion will affect the storage medium is another matter but they will be intact.
Exactly, they’re down there somewhere and I expect further to that intact. So it’s a bit of a strange thing to that “apart from the engines and landing gear there’s nothing down there worth finding” or words to that effect. 
aeropilot said:
Leptons said:
hidetheelephants said:
There's no chance of that, FDRs have survived far more violent crashes and being incinerated. Whether prolonged immersion will affect the storage medium is another matter but they will be intact.
Exactly, they’re down there somewhere and I expect further to that intact. So it’s a bit of a strange thing to that “apart from the engines and landing gear there’s nothing down there worth finding” or words to that effect. Leptons said:
hidetheelephants said:
There's no chance of that, FDRs have survived far more violent crashes and being incinerated. Whether prolonged immersion will affect the storage medium is another matter but they will be intact.
Exactly, they’re down there somewhere and I expect further to that intact. So it’s a bit of a strange thing to that “apart from the engines and landing gear there’s nothing down there worth finding” or words to that effect. I’m unsure whether they use tapes still or hard drives?
The Wookie said:
Megaflow said:
eliot said:
Megaflow said:
I see there are a couple of chancers still claiming to know where it is. There is Richard Godfrey with his WSPR.
I wouldn’t consider him a chancer, he’s correlated the data with other similar flights to prove the theory.It is credible imo - especially as a licensed ham.
https://mh370.radiantphysics.com/2021/12/19/wspr-c...
magpie215 said:
eliot said:
not familiar with the plane - but can you pull the breaker for the fdr - given that other things like adsb were pulled/disabled.
It will have a CB that can be pulled.DaveTheRave87 said:
The Cockpit Voice Recorder starts overwriting itself after 2 hours so it's very unlikely that we'll hear what the pilots were saying or doing when the plane went off course.
Are you sure about that? If that’s the case it’s borderline bizarre. My iPhone can record voice for longer than that without running out of memory. My £30 Amazon camera can record sound and video for 3 days straight…Leptons said:
Are you sure about that? If that’s the case it’s borderline bizarre. My iPhone can record voice for longer than that without running out of memory. My £30 Amazon camera can record sound and video for 3 days straight…
It is the case. Most CVRs only record 30 minutes or so on a continually erasing loop. More modern ones run for a couple of hours. Various bodies like the FAA and EASA are pushing for longer record times that are easily possible with modern technology (and have been for ages).As hidetheelephants said, flight crews are wary of this because of the potential for employers snooping on their employees under the guise of safety and monitoring performance. That is already done by the huge amount of flight data and documentation that each flight generates in the form of both live data transmissions and subsequent downloads. Pilots say that those will tell the airline how well, safely and efficiently they are flying the aircraft and the airline doesn't need to listen to their conversations to do so.
Key concessions pilots secured when CVRs were introduced was that the record time was relatively limited (only the last 30 minutes) and that they had the ability to erase the recording using the CVR controls on the flight deck at the end of an uneventful flight.
It's also a rare accident that really needs more than 30 mins or so of recording. A relatively 'slow and long' incident like United 232 only lasted 45 minutes. The Gimli Glider was all over in 17 minutes. Even JAL 123 was less than 30 minutes from decompression to crash.
2xChevrons said:
Leptons said:
Are you sure about that? If that’s the case it’s borderline bizarre. My iPhone can record voice for longer than that without running out of memory. My £30 Amazon camera can record sound and video for 3 days straight…
It is the case. Most CVRs only record 30 minutes or so on a continually erasing loop. More modern ones run for a couple of hours. Various bodies like the FAA and EASA are pushing for longer record times that are easily possible with modern technology (and have been for ages).As hidetheelephants said, flight crews are wary of this because of the potential for employers snooping on their employees under the guise of safety and monitoring performance. That is already done by the huge amount of flight data and documentation that each flight generates in the form of both live data transmissions and subsequent downloads. Pilots say that those will tell the airline how well, safely and efficiently they are flying the aircraft and the airline doesn't need to listen to their conversations to do so.
Key concessions pilots secured when CVRs were introduced was that the record time was relatively limited (only the last 30 minutes) and that they had the ability to erase the recording using the CVR controls on the flight deck at the end of an uneventful flight.
It's also a rare accident that really needs more than 30 mins or so of recording. A relatively 'slow and long' incident like United 232 only lasted 45 minutes. The Gimli Glider was all over in 17 minutes. Even JAL 123 was less than 30 minutes from decompression to crash.
surveyor said:
But it's not. If there is a crash that 30 minutes works. If there is an 'event' then that time restriction is far too small, and does not really make sense. If there is a delete button to be used at the end of the flight why not just record the whole flight? And beat up pilots who accidently delete the recording when there has been an 'event'.
If a mid-flight event occurs the crew either pop the CVR circuit breaker (one of the reasons the breaker is accessible to them) thus preserving the recording or the CVR has a dedicated 'Event' button that pauses the recording. They're also supposed to pull the breaker after a forced landing, runway excursion, ditching, survivable crash etc. Because there have been cases where the plane has made a safe landing or survivable crash and then it's been more than the CVR record time before the power is turned off (because people have other things on their mind in an evacuation scenario or even a less severe but adrenaline-heavy scenario) and so the CVR recording of the incident is lost. Of course more severe crashes usually end with the power to the CVR being cut at impact.
And yes, there have been cases where crew 'forgetting' to pull the breaker or pushing the erase button 'by muscle memory' has seemed awfully convenient for them. I believe some CVRs require 'two hands' to erase the recording - the button in the cockpit and another one in the equipment bay or a wheel well need to be pressed simultaneously.
E: As to, 'why not record the whole flight?'. Originally that wasn't practical when CVRs were high-grade physical tapes or primitive solid state mediums. So 30 minutes was both a practical limit and a concession to pilots. Two hours has been introduced as technology has improved and pilots are more tolerant of what their 1960s and 1970s forebears would have viewed as intolerable snooping into their flying and their command. When head office can download data to check your fuel burn against the company average or see if your touchdowns are conforming with the speeds and distances laid out in the SOPs, having two hours of voice recording that will in all likelyhood get erased anyway is less of an issue.
And of course not all pilots are of that attitude. Some take it that if there isn't an incident then the recording will never get listened to and if there is then, if they are doing the job as the company, the regulations, professionalism and good airmanship require then the CVR would actually be their strongest advocate.
Edited by 2xChevrons on Wednesday 13th March 10:21
Leptons said:
My iPhone can record voice for longer than that without running out of memory. My £30 Amazon camera can record sound and video for 3 days straight…
Bear in mind that the MH370 777 was manufactured five years before Steve Jobs stepped on stage to reveal the first iPhone - simply because consumer technology has moved on doesn't mean that similar capacity is incorporated into aircraft systems at anywhere near the same rate, and generally only after a long and arduous certification process - and fitting updated equipment into older airframes is largely undertaken only if there is a sound commercial or safety reason for doing so. As it happens, the FAA is finalising a minimum 25 hour CVR recording time, but that will only apply to newly manufactured aircraft, and that regulation would only apply from 12 months after the effective date of the final rule being confirmed.
2xChevrons said:
As hidetheelephants said, flight crews are wary of this because of the potential for employers snooping on their employees under the guise of safety and monitoring performance. That is already done by the huge amount of flight data and documentation that each flight generates in the form of both live data transmissions and subsequent downloads. Pilots say that those will tell the airline how well, safely and efficiently they are flying the aircraft and the airline doesn't need to listen to their conversations to do so.
Given the huge safety implications, and the responsibility of transporting 300 people safely, I'd say the need to record everything outweighs any snooping considerations. As mentioned above, recording voices for several hours is technically trivial these days. Upgrading the memory in the old CVRs should be similarly possible.M4cruiser said:
2xChevrons said:
As hidetheelephants said, flight crews are wary of this because of the potential for employers snooping on their employees under the guise of safety and monitoring performance. That is already done by the huge amount of flight data and documentation that each flight generates in the form of both live data transmissions and subsequent downloads. Pilots say that those will tell the airline how well, safely and efficiently they are flying the aircraft and the airline doesn't need to listen to their conversations to do so.
Given the huge safety implications, and the responsibility of transporting 300 people safely, I'd say the need to record everything outweighs any snooping considerations. As mentioned above, recording voices for several hours is technically trivial these days. Upgrading the memory in the old CVRs should be similarly possible.I believe that generally if a CVR fails before flight the aircraft is still allowed to operate a (small) number of sectors before the equipment has to be fixed, recognition that a broken CVR isn't going to make the aircraft itself any less safe to operate.
eharding said:
but from a commercial or safety perspective it simply isn't worth it - invariably if the recorder has been in a state where the data of interest has been over-written, the crew is still in a position to help the investigators
If the Malaysia aircraft is ever found (in the Indian Ocean), and if the CVR is readable, then the families would disagree with you, because it would have been worth it. The crew are in no position to help.Leptons said:
DaveTheRave87 said:
The Cockpit Voice Recorder starts overwriting itself after 2 hours so it's very unlikely that we'll hear what the pilots were saying or doing when the plane went off course.
Are you sure about that? If that’s the case it’s borderline bizarre. My iPhone can record voice for longer than that without running out of memory. My £30 Amazon camera can record sound and video for 3 days straight…Cvr of the event was overwritten because the breaker wasn't pulled and tagged.
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