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NSEU
June 13, 2025, 07:40:00 GMT permalink Post: 11900117 |
Flight Radar 24 gives altitude with standard baro 1013mb. You'd have to know the QNH at the time to get the correct altitude.
Subjects: None |
NSEU
June 30, 2025, 13:14:00 GMT permalink Post: 11913615 |
A maintenance engineer looked into the gear tilt issue. The 787 has no hydraulic sequencing valves like traditional Boeings, and the bogie tilt command is simply generated by gear lever movement. So, I suppose the doors dropping before or after the gear tilting may simply be who gets there first.
That is not to say loss of hydraulics also causes "toes down" because of bogie imbalance or aerodynamics (as previously mentioned). Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Gear Lever |
NSEU
June 30, 2025, 13:35:00 GMT permalink Post: 11913630 |
If rigorously applied, an "engine thrust balancer" would cause the good engine to fail if something happened to the other one. Surely there is some logic in there somewhere to give up and disconnect past a certain amount of adjustment??
* as for why not before, probably because it didn't happen that way or in Boeing's worst nightmare some weird corner case in the software that does this if certain parameters are in rare combination. Subjects (links are to this post in the relevant subject page so that this post can be seen in context): FCOM Parameters |
NSEU
June 30, 2025, 13:59:00 GMT permalink Post: 11913644 |
There are several ways that the HPSOV can close: An EEC (engine ECU) can close the upstream Fuel Metering Valve (FMV) electronically, so the HPSOV will lose its opening pressure. The HPSOV can be acted on by a Shutoff Solenoid Valve (which directs fuel pressure in an opposite manner to the pressure coming from the Fuel Metering Valve). Unfortunately, the diagram I am using is truncated, and I can't see if the Shutoff Solenoid Valve is magnetically latched in its last commanded position like typical fuel shutoff valves. Nor can I see what controls it. I suspect things like the respective cockpit fire handle and fuel cutoff lever, but also EEC commands. There is probably a copyright on the diagram, so I won't post it here. Perhaps someone can fill in the gaps for me? Subjects (links are to this post in the relevant subject page so that this post can be seen in context): FCOM Fuel (All) Fuel Cutoff Fuel Cutoff Switches GEnx (ALL) High Pressure Shutoff Valve |
NSEU
June 30, 2025, 14:10:00 GMT permalink Post: 11913661 |
ADS-B stops 330' from the end of the runway, well before top of climb. A previous poster stated that ADS-B granularity on the 787 was 25'. As the aircraft obviously climbed higher than 71', it's reasonable to assume that ADS-B was about to transmit 96' when the electrics failed. Looking at the CCTV, subjectively, the aircraft reaches the height of a wing about 7s after rotate and top of climb about 7s later.
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): ADSB CCTV |
NSEU
July 13, 2025, 06:47:00 GMT permalink Post: 11921059 |
The pin groupings are usually in 3's. e.g. 1,2,3 is one pole 4,5,6 is another 7,8,9 etc. I have one 787 fuel control diagram which suggests 3, but there may be more Thanks in advance Subjects (links are to this post in the relevant subject page so that this post can be seen in context): FDR |
NSEU
July 13, 2025, 06:59:00 GMT permalink Post: 11921065 |
Would not expect an FDR dedicated pole. They
might
pull the FCS position from the FADEC, since what really matters is what the FADEC receives as a command. I would expect two poles dedicated to the two circuits, one routed to each FADEC channel, and the others to the non-FADEC-reset-command functions.
The 747 has 3 poles per switch. To send signals to all the systems it needs to, splices and multi-output relays are involved. On some aircraft there are even separate power sources going to some of these poles. Subjects (links are to this post in the relevant subject page so that this post can be seen in context): FADEC FDR Spar Valves |
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