Air India 787 crashes on take off 3

[LittleInch]

A full 787-8 has crashed shortly after take off in ahmedabad.

Basically barely got off the ground then look like its trying to land in this video.

Air India flight to London Gatwick crashes in Ahmedabad with more than 240 people onboard – latest updates

Plane for flight AI171 was carrying 242 people including 169 Indians and 53 Britons, says Air India

www.theguardian.com

Specualtion that they pulled flaps up instead of gear up and basically didn't have enough lift so it looks like a gentle stall right into a built up area.

Looks to be flaps up, slats/ nose flaps down and gear down which is very odd.

 

[Debirlfan]

Well your water leaks comment is timely, as FAA has issue an AD dated 16 June 25, with water leak AD's and inspections going back approximately 4 years.

I think that's the video I saw.

 

[LittleInch]

"and we now know a 787 engine will not keep running with loss of electrical power, as pre-FADEC engines were capable of doing"

Where did this get stated or confirmed?

I'm not saying you're wrong, just I haven't seen anything that states this with any certainty.

 

[Alistair_Heaton]

I don't think it does die. But it just stays as it is with fuel flow.

You need to use the fuel valve to stop it running or flood it with water

 

[Garbage1]

My memory is the information was contained in the B787 ME&AV Type 1 Training Manual. Link is posted again below, but document has been removed.

EEU controls fuel valve in 787, and FMU controls fuel metering. How are those functions performed with total loss of electricity or control communications? Falisafe mode appeared to be spring loaded fuel shutoff valve, open when energized. Previously it is documented in 2015 that messages caused rollback of dual engines after 248 days of not powering down.

Interesting side note is the removed training manual was from a Chinese training site.

https://archive.org/details/b787-meav-type-1-training-manual

 

[TugboatEng]

If a control system is using PWM to manage fuel flow it's not going to flow any fuel if power is lost.

 

[SnTMan]

Just watched the latest Maximus Av video on the water leak. I don't know how credible the guy is but he does not know the meaning of "potable water'. See 2:37 in the vid.

 

[Alistair_Heaton]

Apparently the fail condition is dependant on the aircraft type manufacturer.

Cfm56 is case in point apparently.

 

[TugboatEng]

What is the ideal fail condition? Off, idle, 50% power, 80%, 100%, last valid input?

 

[Garbage1]

When you lose electro-hydraulic power to FMU, where is electrical power coming from to hold or move electro-hydraulic fuel metering servo to any failsafe position? Would it likely be the spring mechanical pressure closing the fuel shut off valve? Would think in case of engine fire, fuel shutoff valve is immediate way to starve engine of fuel.

 

[Alistair_Heaton]

What it was it was set at by some.

To be honest i don't really know what cause's them to fail. With cross talk the other side will manage the live engine if its shut down as far as i can tell. Its 6 chanels need to die.

Personally I really don't know what the best idea is.

I don't like the idea of the engine dies, unless i want it too and I am ready.

 

[Alistair_Heaton]

When you lose electro-hydraulic power to FMU, where is electrical power coming from to hold or move electro-hydraulic fuel metering servo to any failsafe position? Would it likely be the spring mechanical pressure closing the fuel shut off valve?

Thats how it works in 787. I don't know about other types boeing. Airbus it stays how it is you have to manually close the fuel valve to get rid of power.

 

[Garbage1]

I don't like the fact that the 787 FADEC engine controls does not have battery backup, like apparently Airbus does. Boeing never expected loss of all 6 generators at once, but it happen in Japan years ago, due to the 248 day power on messaging fault. This time it could be water leaks took out common core processing/control of airplane by short. Common Core processing control goes down, everything fails, whether water induced or software induced. The Common core design without water protection designed in, could be next FAA mandated design change?

I don't coneider water dam floor tape as mentioned in FAA's AD's to be an adquate robust water protection method for critical common core system.

 

[Alistair_Heaton]

I wonder if the same fadec philosophy is the same on other Boeing types.

Ie what's it do on the max with it's 1960's electrical system which they are having to change to get the max 10 certified.

 

[Garbage1]

But in reality in Japan and India, all 6 generators likely did not fail. Rather the Single Point Failure Common Core System is likely root problem in both cases.