Air India 787 crashes on take off 2

[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.

 

[Alistair_Heaton]

You wouldn't touch anything that low.

Gear would be up by the time we did.

Even engine fire we don't start working on until 400ft.

 

[waross]

If vapor lock were real it should be endemic to specific vehicles

Endemic to flat head Ford V8s up until the early 50s.
The fuel pump was mounted High above the intake manifold at the back of the block.
Other Detroit engines had the fuel mounted low down on the side of the block.

There was very little head difference to the gas tank and vapour lock was not a problem.
Anecdote: The fuel pump on the flatties was operated by a push rod riding the last lobe on the camshaft.
The clearances and spacing was not always optimum.
A fix for an engine that was prone to vapour lock was to put a disk of leather, such as cut out of a belt, inside the little cup on the top of the push rod. That often gave the fuel pump a greater stroke and solved the problem.
A lot of the old Fords never did vapour lock but some engines did repeatedly.

 

[Garbage1]

I have to ask the question but how do you know you weren't flooded? That would also resolve itself as the engine cooled off.

If vapor lock were real it should be endemic to specific vehicles or pandemic to the entire automotive industry and it isn't. Instead some older vehicles experience driveability issues on but days. This reads as a wear issue.

I guess you are arguing that when under hood temps rose at shutdown, the fuel in the carb float bowl and fuel in line between mechanical diaphragm pump and carb was vaporized and sitting on top of the throttle body of the carb, thus flooding the engine upon cranking? If that were case, then why did changing from a mechanical fuel pump to an electric fuel pump with check valve cure the problem of vapor forming in fuel lines that diaphragm pump could not pump?

Ok it is official for AMC 360's Vapor Locking, as per our favorite source, You Tubers... Although the far better approach is an electric fuel pump with regulator to dial pressure down to match OEM fuel pressure.

 

[Garbage1]

Endemic to flat head Ford V8s up until the early 50s.
The fuel pump was mounted High above the intake manifold at the back of the block.
Other Detroit engines had the fuel mounted low down on the side of the block.

There was very little head difference to the gas tank and vapour lock was not a problem.
Anecdote: The fuel pump on the flatties was operated by a push rod riding the last lobe on the camshaft.
The clearances and spacing was not always optimum.
A fix for an engine that was prone to vapour lock was to put a disk of leather, such as cut out of a belt, inside the little cup on the top of the push rod. That often gave the fuel pump a greater stroke and solved the problem.
A lot of the old Fords never did vapour lock but some engines did repeatedly.

Leather was a fix all , back in the day! Thinking about leather main bearings....... My case was an AMC 360 V8, and it is endemic also to those engines used in Jeeps. The marine engine was a Yamaha 1200 smoker, and that case as I remember was related to having to use Corn Fed Gasoline on that trip.....

 

[LittleInch]

Can we keep this post on track here please.... This belongs in the auto forum.

 

[Garbage1]

Can we keep this post on track here please.... This belongs in the auto forum.

Disagree. Captain Steeve is the one who put vapor lock main stream as potential theory for fuel starvation of AI 171. Whether a jet engine or auto engine, same principles of fuel distribution would apply. Vapor lock is not something very many younger generations would be familar with. But the old 'Flat Heads' lived and breathed it.

 

[Alistair_Heaton]

Must admit I am wondering if it's possible on an aircraft engine that's certified for positive and negative G.


We have motive flow/ jet pumps on the cold side of the fire wall.

 

[Garbage1]

Must admit I am wondering if it's possible on an aircraft engine that's certified for positive and negative G.


We have motive flow/ jet pumps on the cold side of the fire wall.

I don't think it is possible on jets, as fuel pumps provide lots of positive pressure and there were full tanks of jet fuel. So no sucking vapor. And it really hurt Captain Steve's credibility, IMHO.

 

[Alistair_Heaton]

Most aircraft engines to my knowledge don't actually need a pump to continue to run.

The volume of fuel being used and the size of the piping means it gets sucked if the pumps fail.

In cruise I am using 900 kg/hr which arrives in a 3/4 pipe. Take off it's 1800kg/hr through the same pipe per engine.

 

[MechinNC]

In my mind possible that some sort of complete electrical failure caused the in-tank AC fuel pumps to quit. This would cause a RAT drop even before the engines spooled down completely and be triggered by loss of AC generation or loss of hydraulic pressure.

The engines have gear driven fuel pumps that would still work. But without tank pumps running, gear driven fuel pump may not have gone to full flow. Not vapor lock, technically, but dissolved gasses may have limited gear pump flow. NPSH thingy...

Or loss of power combined with software who-knows-what may have caused engines to ramp down. No time to recover.

I fear that the FDR's may not have that much info. Not so much due to loss of power (I think they have internal batts), but the power loss may have caused other devices feeding inputs to the FDR to go silent. So the operating FDR may have little to record.

Could be a complicated investigation. I would figure by now they could have downloaded the things and at least had some very preliminary findings. I would expect those to be published quickly to help the safety of the 787 fleet. The silence to this point is very loud....

 

[Garbage1]

If this is accurate, you still have EEC control over Engine Fuel Valve. Shows 2 stages of fuel pumps, and spar fuel valve.

 

[LittleInch]

Disagree. Captain Steeve is the one who put vapor lock main stream as potential theory for fuel starvation of AI 171. Whether a jet engine or auto engine, same principles of fuel distribution would apply. Vapor lock is not something very many younger generations would be familar with. But the old 'Flat Heads' lived and breathed it.

I meant people reminiscing about 50 year old cars.....

I'm becoming more convinced that the investigators are now pretty sure about what happened ( dual engine shutdown) , but can't see or can't prove why it happened.

Flight deck and control system destroyed and data missing or not available.

 

[Garbage1]

I meant people reminiscing about 50 year old cars.....

Good, then perhaps I was not the subject of your post,, since the JEEP I was talking about is only 43 years old today.......

Now the Flat Heads go way beyond 50 years back....



I would expect the EEC/FMC injector(s) would be normally closed without signal to open, based upon scheduled fuel mapping, otherwise engine flooding. Thus loss of electric power would stop fuel flow thru the injector(s) via digital control. Loss of power to fuel tank pump would lower fuel pressure in-line between first stage and second stage pumps. Now the firewall fuel shutoff valve may very well be power open and power close, so it could have remained in open position during this event, and not be an issue? The Lithium Ion Battery does not appear to have provided 1st level critical backup power to keep engines running. By design or battery was beyond useful life?

 

[waross]

thus flooding the engine upon cranking?

Wrong.

 

[Garbage1]

Wrong.

AGREE 100%!