NSEU
2025-06-13T07:40:00
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
2025-06-30T13:14:00
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: Gear Retraction MLG Tilt

NSEU
2025-06-30T13:35:00
permalink Post: 11913630

Quote:

Originally Posted by island_airphoto

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.

The FCOM explains that the system only operates when there is a large thrust to weight ratio and will maintain the required climb performance. If applied during an engine out, it will provide directional control only when airspeed drops below normal operating speeds.

Subjects: FCOM Parameters

1 user liked this post.

NSEU
2025-06-30T13:59:00
permalink Post: 11913644

Quote:

Originally Posted by Phantom4

Have the spring loaded Fuel Shut Off Valves been examined by GE on both engines???

Why would spring loaded valves fail on both engines? The final valve in the GEnx Fuel Metering Unit (FMU) before the fuel flow meter and things like the fuel nozzles, is called the HPSOV and is spring loaded to closed, but fuel from the Fuel Metering Valve (FMV) can keep it open with minimal pressure (certainly enough presssure for engine start). Tank electric pumps and the engine-mounted, mechanically-driven two-stage pump supply fuel to the Fuel Metering Valve. During main tank pump failure, the engine mounted pump suction feeds the engine. There are altitude limitations during climb (according to the FCOM).

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: FCOM Fuel (All) Fuel Cutoff Fuel Pumps GEnx (ALL) High Pressure Shutoff Valve

NSEU
2025-06-30T14:10:00
permalink Post: 11913661

Quote:

Originally Posted by jdaley

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.

By wingspan, I mean one tip to the other tip.

Subjects: ADSB CCTV

Posts by user "NSEU" [Posts: 5 Total up-votes: 1 Pages: 1]