ignorantAndroid Page: 2 of 2

ignorantAndroid
July 14, 2025, 05:15:00 GMT
permalink Post: 11921848

Quote:

Originally Posted by Lonewolf_50

I think we'll need to agree to disagree, since those cameras won't prevent any accident (all they'll do is improve post mortems)

That would apply to FDRs and CVRs as well. The purpose of investigating accidents is to prevent future accidents.

Subjects: None

9 recorded likes for this post.

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

ignorantAndroid
July 14, 2025, 07:02:00 GMT
permalink Post: 11921875

Looking at some past FDR data, it appears that the fuel cutoff switches are sampled at 1 Hz, but the actual valve position is sampled at 4 Hz. The position of the fire switch (fire handle) is also recorded. N1 and N2 are sampled at 1 Hz.

Subjects FDR Fuel (All) Fuel Cutoff Fuel Cutoff Switches

Links are to this post in the relevant subject page so that this post can be seen in context.

5 recorded likes for this post.

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

ignorantAndroid
July 14, 2025, 21:32:00 GMT
permalink Post: 11922481

Quote:

Originally Posted by tdracer

Again, not familiar with the specifics of the 787, but on the 747-400/-8, one pole of the fuel switch feeds EICAS - which uses it in various message logic - and sends it out to any other aircraft systems that use it. There is "Digital Flight Data Acquisition Unit) DFDAU (pronounced Daff Du) that takes all the various system digital signals, sorts them and provides them to the DFDR and QAR. The 787 has something similar to the DFDAU but I don't recall what it's called.

It was stated earlier that 2 of the poles in the switch are wired to separate Remote Data Concentrators. The RDCs feed data into the Common Data Network (essentially an Ethernet LAN).

The EAFRs simply sniff the required data from the CDN, so there's no DFDAU as such.

For some parameters, including the fuel cutoff switches, the EAFRs also record a "Source Index." For the fuel cutoff switches, there are 4 sources numbered 1 through 4 as well as a valid/invalid flag. I don't know what the sources are, but perhaps they're the 2 RDCs plus the 2 channels of the EEC/FADEC. It appears that source 1 (the default) is not the EEC.

Subjects DFDR Digital Flight Data Acquisition Unit EICAS Fuel (All) Fuel Cutoff Fuel Cutoff Switches Parameters

Links are to this post in the relevant subject page so that this post can be seen in context.

1 recorded likes for this post.

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

ignorantAndroid
July 16, 2025, 06:00:00 GMT
permalink Post: 11923427

Quote:

Originally Posted by Musician

Where is the RadAlt antenna on a 787? Is it in the nose, or further back between the main gears?

Subjects: None

3 recorded likes for this post.

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

ignorantAndroid
July 17, 2025, 21:08:00 GMT
permalink Post: 11924625

Quote:

Originally Posted by Sailvi767

The displayed EICAS messages are very different when an engine is shut down via the fuel cutoff switch vice other reasons. The EAFR records those messages. I am quite sure they have eliminated the TCMA as a problem in this accident.

Indeed, there are dedicated parameters for TCMA:

Eng1_TCMA_Shutdown_Local_EEC_A
Eng1_TCMA_Shutdown_Local_EEC_B
Eng2_TCMA_Shutdown_Local_EEC_A
Eng2_TCMA_Shutdown_Local_EEC_B

Subjects EAFR EICAS Fuel (All) Fuel Cutoff Fuel Cutoff Switches Parameters

Links are to this post in the relevant subject page so that this post can be seen in context.

2 recorded likes for this post.

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

ignorantAndroid
January 24, 2026, 08:20:00 GMT
permalink Post: 12026235

Quote:

Originally Posted by B2N2

The report is here:
https://avherald.com/files/Senate%20...12,%202026.pdf

For context, that report appears to be from the Foundation for Aviation Safety. FAS was founded by Ed Pierson, a former 737 production manager and self-proclaimed Boeing whistleblower (even though he didn't blow the whistle until after the MAX crashes). He made some vague and (in my opinion) unsubstantiated claims that the accidents had something to do with production issues. His 'reports' on the MAX are just as vague and (in my opinion) ridiculous as this one.

Subjects: None

No recorded likes for this post (could be before pprune supported 'likes').

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

ignorantAndroid
January 26, 2026, 22:24:00 GMT
permalink Post: 12027684

Quote:

Originally Posted by Kiltrash

The bottom line will be in the report as" The fuel switches were operated incorrectly for reasons unknown "

Like the Marie Celeste it will be one of the great unknowns

Unless the CVR captured the sounds of a physical struggle. I suspect that those who have heard it have a better understanding of what happened than we do.

Subjects CVR Fuel (All) Fuel Cutoff Switches

Links are to this post in the relevant subject page so that this post can be seen in context.

2 recorded likes for this post.

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

ignorantAndroid
February 02, 2026, 06:16:00 GMT
permalink Post: 12030938

Mr. Thompson is still at it, unfortunately. Looks like he's posted 4 videos in the past 4 days.

Anyone who's entertaining his theories should be aware that he's gone through at least 3 of them. I know because I was arguing with him on Reddit before he even started with the videos. Every time one idea is debunked, he comes up with another one.

Aside from making several incorrect assumptions about the 787 systems, his latest theory claims that the battery reversed its polarity, something that's not known to be physically possible.

Subjects: None

6 recorded likes for this post.

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

ignorantAndroid
February 03, 2026, 22:12:00 GMT
permalink Post: 12031878

Quote:

Originally Posted by Lifer01

For reference, Boeing does not provide a procedure to replace the cut-off switches. If there is an issue with a fuel cut-off switch, the whole thrust control module is to be replaced, ie. the throttle levers and cut-off switches are in one module.

I believe this has been the case since before the AI accident.

In this video from Stig Aviation, at 17:33, he states, "You can change the switches individually because it gives you the option in the maintenance manual."

Subjects Fuel (All) Fuel Cutoff Fuel Cutoff Switches

Links are to this post in the relevant subject page so that this post can be seen in context.

3 recorded likes for this post.

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

ignorantAndroid July 14, 2025, 05:15:00 GMT permalink Post: 11921848	Quote: Originally Posted by Lonewolf_50 I think we'll need to agree to disagree, since those cameras won't prevent any accident (all they'll do is improve post mortems) That would apply to FDRs and CVRs as well. The purpose of investigating accidents is to prevent future accidents. Subjects: None 9 recorded likes for this post. Reply to this quoting this original post. You need to be logged in. Not available on closed threads.
ignorantAndroid July 14, 2025, 07:02:00 GMT permalink Post: 11921875	Looking at some past FDR data, it appears that the fuel cutoff switches are sampled at 1 Hz, but the actual valve position is sampled at 4 Hz. The position of the fire switch (fire handle) is also recorded. N1 and N2 are sampled at 1 Hz. Subjects FDR Fuel (All) Fuel Cutoff Fuel Cutoff Switches Links are to this post in the relevant subject page so that this post can be seen in context. 5 recorded likes for this post. Reply to this quoting this original post. You need to be logged in. Not available on closed threads.
ignorantAndroid July 14, 2025, 21:32:00 GMT permalink Post: 11922481	Quote: Originally Posted by tdracer Again, not familiar with the specifics of the 787, but on the 747-400/-8, one pole of the fuel switch feeds EICAS - which uses it in various message logic - and sends it out to any other aircraft systems that use it. There is "Digital Flight Data Acquisition Unit) DFDAU (pronounced Daff Du) that takes all the various system digital signals, sorts them and provides them to the DFDR and QAR. The 787 has something similar to the DFDAU but I don't recall what it's called. It was stated earlier that 2 of the poles in the switch are wired to separate Remote Data Concentrators. The RDCs feed data into the Common Data Network (essentially an Ethernet LAN). The EAFRs simply sniff the required data from the CDN, so there's no DFDAU as such. For some parameters, including the fuel cutoff switches, the EAFRs also record a "Source Index." For the fuel cutoff switches, there are 4 sources numbered 1 through 4 as well as a valid/invalid flag. I don't know what the sources are, but perhaps they're the 2 RDCs plus the 2 channels of the EEC/FADEC. It appears that source 1 (the default) is not the EEC. Subjects DFDR Digital Flight Data Acquisition Unit EICAS Fuel (All) Fuel Cutoff Fuel Cutoff Switches Parameters Links are to this post in the relevant subject page so that this post can be seen in context. 1 recorded likes for this post. Reply to this quoting this original post. You need to be logged in. Not available on closed threads.
ignorantAndroid July 16, 2025, 06:00:00 GMT permalink Post: 11923427	Quote: Originally Posted by Musician Where is the RadAlt antenna on a 787? Is it in the nose, or further back between the main gears? Subjects: None 3 recorded likes for this post. Reply to this quoting this original post. You need to be logged in. Not available on closed threads.
ignorantAndroid July 17, 2025, 21:08:00 GMT permalink Post: 11924625	Quote: Originally Posted by Sailvi767 The displayed EICAS messages are very different when an engine is shut down via the fuel cutoff switch vice other reasons. The EAFR records those messages. I am quite sure they have eliminated the TCMA as a problem in this accident. Indeed, there are dedicated parameters for TCMA: Eng1_TCMA_Shutdown_Local_EEC_A Eng1_TCMA_Shutdown_Local_EEC_B Eng2_TCMA_Shutdown_Local_EEC_A Eng2_TCMA_Shutdown_Local_EEC_B Subjects EAFR EICAS Fuel (All) Fuel Cutoff Fuel Cutoff Switches Parameters Links are to this post in the relevant subject page so that this post can be seen in context. 2 recorded likes for this post. Reply to this quoting this original post. You need to be logged in. Not available on closed threads.
ignorantAndroid January 24, 2026, 08:20:00 GMT permalink Post: 12026235	Quote: Originally Posted by B2N2 The report is here: https://avherald.com/files/Senate%20...12,%202026.pdf For context, that report appears to be from the Foundation for Aviation Safety. FAS was founded by Ed Pierson, a former 737 production manager and self-proclaimed Boeing whistleblower (even though he didn't blow the whistle until after the MAX crashes). He made some vague and (in my opinion) unsubstantiated claims that the accidents had something to do with production issues. His 'reports' on the MAX are just as vague and (in my opinion) ridiculous as this one. Subjects: None No recorded likes for this post (could be before pprune supported 'likes'). Reply to this quoting this original post. You need to be logged in. Not available on closed threads.
ignorantAndroid January 26, 2026, 22:24:00 GMT permalink Post: 12027684	Quote: Originally Posted by Kiltrash The bottom line will be in the report as" The fuel switches were operated incorrectly for reasons unknown " Like the Marie Celeste it will be one of the great unknowns Unless the CVR captured the sounds of a physical struggle. I suspect that those who have heard it have a better understanding of what happened than we do. Subjects CVR Fuel (All) Fuel Cutoff Switches Links are to this post in the relevant subject page so that this post can be seen in context. 2 recorded likes for this post. Reply to this quoting this original post. You need to be logged in. Not available on closed threads.
ignorantAndroid February 02, 2026, 06:16:00 GMT permalink Post: 12030938	Mr. Thompson is still at it, unfortunately. Looks like he's posted 4 videos in the past 4 days. Anyone who's entertaining his theories should be aware that he's gone through at least 3 of them. I know because I was arguing with him on Reddit before he even started with the videos. Every time one idea is debunked, he comes up with another one. Aside from making several incorrect assumptions about the 787 systems, his latest theory claims that the battery reversed its polarity, something that's not known to be physically possible. Subjects: None 6 recorded likes for this post. Reply to this quoting this original post. You need to be logged in. Not available on closed threads.
ignorantAndroid February 03, 2026, 22:12:00 GMT permalink Post: 12031878	Quote: Originally Posted by Lifer01 For reference, Boeing does not provide a procedure to replace the cut-off switches. If there is an issue with a fuel cut-off switch, the whole thrust control module is to be replaced, ie. the throttle levers and cut-off switches are in one module. I believe this has been the case since before the AI accident. In this video from Stig Aviation, at 17:33, he states, "You can change the switches individually because it gives you the option in the maintenance manual." You Tube Subjects Fuel (All) Fuel Cutoff Fuel Cutoff Switches Links are to this post in the relevant subject page so that this post can be seen in context. 3 recorded likes for this post. Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

Posts by user "ignorantAndroid" [Posts: 29 Total up-votes: 32 Page: 2 of 2]¶