D Bru
2025-06-28T17:04:00
permalink Post: 11912578

Quote:

Originally Posted by Someone Somewhere

I am not certain on that. Remember the 737 didn't have them on the standby bus (Jeju). The NTSB doc states they're powered from the L/R 28VDC buses on the 787.

This shows the centre TRUs can only power the instrument buses not the L/R DC buses, the RAT can't really power the right TRU without powering both R1/R2 buses, and powering the left TRU would require powering the left 235/115 ATU which would probably be a lot of magnetising current even if not much actual load. The contactor naming supports that.

My money is on the L/R DC buses being unpowered in RAT operation; only the CA/FO instrument buses and the 235VAC backup bus.

That's exactly why I would really recommend reading through the NTSB FDR report on the 2013 JA829J Boston incident helpfully posted by EDLB . There's potentially a wealth of data concerning a to me at least surprisingly number of 2000 of parameters written on a 787 EAFR, that is that at least if there's elec power. Even the 10 min RIPS is useless if there's no data sent from electrically shut off systems.

Last edited by D Bru; 28th Jun 2025 at 17:06 . Reason: deleting a repeat image of the elec system

5 users liked this post.

DaveReidUK
2025-06-28T19:10:00
permalink Post: 11912632

Quote:

Originally Posted by EXDAC

The requirements I have seen indicate that RIPS is applicable only to CVR or the CVR function of an EAFD. If you are aware of any requirement for RIPS to support flight data recording would you please provide a reference.

I believe the GE EAFR continues to function as both FDR and CVR for a minimum of 10 minutes following a power failure.

However you are correct in that the requirements only specify that the CVR functions and the CAM must continue to operate.

PJ2
2025-06-28T19:12:00
permalink Post: 11912634

Quote:

Originally Posted by D Bru

Link to the NTSB Report to which D Bru refers, (@EDLB goes to member’s profile):
Auxiliary Power Unit Battery Fire Japan Airlines Boeing 787-8, JA829J Boston, Massachusetts January 7, 2013

2 users liked this post.

EXDAC
2025-06-28T19:40:00
permalink Post: 11912643

Quote:

Originally Posted by DaveReidUK

I believe the GE EAFR continues to function as both FDR and CVR for a minimum of 10 minutes following a power failure.

I was looking for connector pin data but only found this:

"The front panel contains one connector, J1, and a grounding stud. • J1 provides the main EAFR power supply, Aircraft Data Network, Ethernet Channels A and B, analog audio input, input and output discretes, and other miscellaneous signals."

If RIPS is external and the GE EAFD only has a "main power supply" pin then I agree it seems likely that the flight data function is powered by RIPS.

For RIPS to power only the CVR function I would have expected to see separate main power and RIPS power input pins. I could not find any data except the two page marketing brochure which is not definitive.

3 users liked this post.

AirScotia
2025-06-29T19:49:00
permalink Post: 11913191

I've been travelling without access to internet, but I came across this video a few days ago. I don't know anything about the three guys, but they're apparently retired air accident investigators.

They seem to think that some of the EAFR data is now in the US. Is that actually the case?

1 user liked this post.

za9ra22
2025-06-29T20:02:00
permalink Post: 11913197

Quote:

Originally Posted by AirScotia

They seem to think that some of the EAFR data is now in the US. Is that actually the case?

Nobody here could answer that, but since the authorities in India have said the recorders themselves are there and not going anywhere, I would guess that if any data has been downloaded and shared outside the country, it will be for specific analysis purposes - GE for example.

There's no credible reasons 'three former accident investigators' in the US would have any direct knowledge, and if any third party in the US has been provided access to data, it will have been on the basis that it is not shared. Even that I would doubt, since involved parties are far more likely to already be in India as part of the investigation.

On edit, and mindful of the Mods comments around the closing of the thread previously: I don't speak with any direct knowledge of accident investigations in India, only the UK - and even then with only one experience of civil aviation accident work. But I have been involved (in human factors as investigator and lead) in several UK incidents of scale, and have some familiarity with how these processes are constituted and work... there at least.

Last edited by za9ra22; 29th Jun 2025 at 20:19 . Reason: Clarification

Innaflap
2025-06-30T14:42:00
permalink Post: 11913673

Quote:

Originally Posted by EXDAC

I am not aware of any requirement for a DFDAU (or equivalent) to store any data. I say "or equivalent" because in B717 the DFDAU is not an LRU. It is a functional partition of the VIA.

It's not clear to me that 787 EAFR even requires an external DFDAU. The GE EAFR does not -

"Provides Flight Data Acquisition function of ARINC 664 p7 data parameters \x96 No need for a Digital Flight Data Acquisition Unit (DFDAU)."

ref https://www.geaerospace.com/sites/de...rder-3254F.pdf

In this case, there is still an AU - it's just integrated into the EAFR.

D Bru 2025-06-28T17:04:00 permalink Post: 11912578	Quote: Originally Posted by Someone Somewhere I am not certain on that. Remember the 737 didn't have them on the standby bus (Jeju). The NTSB doc states they're powered from the L/R 28VDC buses on the 787. This shows the centre TRUs can only power the instrument buses not the L/R DC buses, the RAT can't really power the right TRU without powering both R1/R2 buses, and powering the left TRU would require powering the left 235/115 ATU which would probably be a lot of magnetising current even if not much actual load. The contactor naming supports that. My money is on the L/R DC buses being unpowered in RAT operation; only the CA/FO instrument buses and the 235VAC backup bus. That's exactly why I would really recommend reading through the NTSB FDR report on the 2013 JA829J Boston incident helpfully posted by EDLB . There's potentially a wealth of data concerning a to me at least surprisingly number of 2000 of parameters written on a 787 EAFR, that is that at least if there's elec power. Even the 10 min RIPS is useless if there's no data sent from electrically shut off systems. Last edited by D Bru; 28th Jun 2025 at 17:06 . Reason: deleting a repeat image of the elec system 5 users liked this post.
DaveReidUK 2025-06-28T19:10:00 permalink Post: 11912632	Quote: Originally Posted by EXDAC The requirements I have seen indicate that RIPS is applicable only to CVR or the CVR function of an EAFD. If you are aware of any requirement for RIPS to support flight data recording would you please provide a reference. I believe the GE EAFR continues to function as both FDR and CVR for a minimum of 10 minutes following a power failure. However you are correct in that the requirements only specify that the CVR functions and the CAM must continue to operate.
PJ2 2025-06-28T19:12:00 permalink Post: 11912634	Quote: Originally Posted by D Bru That's exactly why I would really recommend reading through the NTSB FDR report on the 2013 JA829J Boston incident helpfully posted by EDLB . There's potentially a wealth of data concerning a to me at least surprisingly number of 2000 of parameters written on a 787 EAFR, that is that at least if there's elec power. Even the 10 min RIPS is useless if there's no data sent from electrically shut off systems. Link to the NTSB Report to which D Bru refers, (@EDLB goes to member’s profile): Auxiliary Power Unit Battery Fire Japan Airlines Boeing 787-8, JA829J Boston, Massachusetts January 7, 2013 2 users liked this post.
EXDAC 2025-06-28T19:40:00 permalink Post: 11912643	Quote: Originally Posted by DaveReidUK I believe the GE EAFR continues to function as both FDR and CVR for a minimum of 10 minutes following a power failure. I was looking for connector pin data but only found this: "The front panel contains one connector, J1, and a grounding stud. • J1 provides the main EAFR power supply, Aircraft Data Network, Ethernet Channels A and B, analog audio input, input and output discretes, and other miscellaneous signals." If RIPS is external and the GE EAFD only has a "main power supply" pin then I agree it seems likely that the flight data function is powered by RIPS. For RIPS to power only the CVR function I would have expected to see separate main power and RIPS power input pins. I could not find any data except the two page marketing brochure which is not definitive. 3 users liked this post.
AirScotia 2025-06-29T19:49:00 permalink Post: 11913191	I've been travelling without access to internet, but I came across this video a few days ago. I don't know anything about the three guys, but they're apparently retired air accident investigators. Safety Critical Information Being Withheld from Air India 787 Crash? - Episode 276 They seem to think that some of the EAFR data is now in the US. Is that actually the case? 1 user liked this post.
za9ra22 2025-06-29T20:02:00 permalink Post: 11913197	Quote: Originally Posted by AirScotia They seem to think that some of the EAFR data is now in the US. Is that actually the case? Nobody here could answer that, but since the authorities in India have said the recorders themselves are there and not going anywhere, I would guess that if any data has been downloaded and shared outside the country, it will be for specific analysis purposes - GE for example. There's no credible reasons 'three former accident investigators' in the US would have any direct knowledge, and if any third party in the US has been provided access to data, it will have been on the basis that it is not shared. Even that I would doubt, since involved parties are far more likely to already be in India as part of the investigation. On edit, and mindful of the Mods comments around the closing of the thread previously: I don't speak with any direct knowledge of accident investigations in India, only the UK - and even then with only one experience of civil aviation accident work. But I have been involved (in human factors as investigator and lead) in several UK incidents of scale, and have some familiarity with how these processes are constituted and work... there at least. Last edited by za9ra22; 29th Jun 2025 at 20:19 . Reason: Clarification
Innaflap 2025-06-30T14:42:00 permalink Post: 11913673	Quote: Originally Posted by EXDAC I am not aware of any requirement for a DFDAU (or equivalent) to store any data. I say "or equivalent" because in B717 the DFDAU is not an LRU. It is a functional partition of the VIA. It's not clear to me that 787 EAFR even requires an external DFDAU. The GE EAFR does not - "Provides Flight Data Acquisition function of ARINC 664 p7 data parameters \x96 No need for a Digital Flight Data Acquisition Unit (DFDAU)." ref https://www.geaerospace.com/sites/de...rder-3254F.pdf In this case, there is still an AU - it's just integrated into the EAFR.

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