Air India Flight AI171 (Boeing 787-8) Crash

What are the chances that Air India failed to comply with a Airworthiness Directive? This plane lost thrust for some crazy reason. I found a AD that relates specifically to this issue in that the plane will cut electrical power (which drives the fuel pumps) when the plane has been active for 248 days continuously. Here's the wording from the AD (AD 2018-20-15 if anyone wants to read it):

We are adopting a new airworthiness directive (AD) for all The Boeing Company Model 787 airplanes. This AD requires a repetitive maintenance task for electrical power deactivation on Model 787 airplanes. This AD was prompted by the determination that a Model 787 airplane that has been powered continuously for 248 days can lose all alternating current (AC) electrical power due to the generator control units (GCUs) simultaneously going into failsafe mode. This condition is caused by a software counter internal to the GCUs that will overflow after 248 days of continuous power. We are issuing this AD to prevent loss of all AC electrical power, which could result in loss of control of the airplane.
 
FowVay said:
What are the chances that Air India failed to comply with a Airworthiness Directive? This plane lost thrust for some crazy reason. I found a AD that relates specifically to this issue in that the plane will cut electrical power (which drives the fuel pumps) when the plane has been active for 248 days continuously. Here's the wording from the AD (AD 2018-20-15 if anyone wants to read it):

We are adopting a new airworthiness directive (AD) for all The Boeing Company Model 787 airplanes. This AD requires a repetitive maintenance task for electrical power deactivation on Model 787 airplanes. This AD was prompted by the determination that a Model 787 airplane that has been powered continuously for 248 days can lose all alternating current (AC) electrical power due to the generator control units (GCUs) simultaneously going into failsafe mode. This condition is caused by a software counter internal to the GCUs that will overflow after 248 days of continuous power. We are issuing this AD to prevent loss of all AC electrical power, which could result in loss of control of the airplane.
Click to expand...
But shouldn’t the engines still be capable of gravity feed even if the fuel pumps lose power?

I don’t understand the B787 but if the fuel pumps quit working on the A320, the engines would still get fuel using gravity feed.
 
I am not 100% certain but I don't think the B787 utilizes any sort of gravity feed for fuel supply. It was designed with a complex system of fuel pumps and cross-feed supply systems.
 
Found this in the B787 manual:

Suction Feed
When main tank fuel pump pressure is low, each engine can draw fuel from its corresponding main
tank through a suction feed line that bypasses the pumps. As the airplane climbs, dissolved air is
released from the fuel in the tank due to the decrease in air pressure. This air may collect in the suction
feed line and restrict fuel flow. At high altitude, thrust deterioration or engine flameout may occur as a
result of the fuel flow reduction.
The dissolved air in the fuel tank eventually depletes after reaching cruise altitude. The depletion time
is dependent upon airplane altitude, fuel temperature, and type of fuel. Once the dissolved air is
depleted, the engine should effectively operate on suction feed.
Fuel pressure can be provided from a main tank with operating fuel pumps to both engines by opening
the fuel crossfeed valve. Continued crossfeed use results in a progressive fuel imbalance.
Fuel

AI search about B787 suction feed:

B787, suction feed, also known as gravity feed, is a method of fuel delivery where the engine draws fuel from the tank using the engine's suction without relying on fuel pumps.
 
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So no suction feed from the center tank and limited suction feed from the main tanks. Now the question is whether there is enough supply to feed those hungry engines under takeoff thrust. I think we're onto something here.
 
Pretty sure the B787 takes off using fuel from the main wing tanks so losing the electric fuel pumps shouldn’t cause any engine problems due to gravity feed.
 
billt460 said:
As far as not having the flaps configured properly for takeoff. Many years back wasn't there a 727 that attempted to takeoff at Detroit, that crashed with a high loss of life?

If I remember correctly the flaps were not extended to takeoff position. They were busy jabbering in the cockpit, instead of paying attention. I think they attributed that behavior to the cause of the crash.
Click to expand...
Someone told me about this crash caused by the pilots taking off with no flaps.

This isn’t what happened with Air India ( or the wrong flaps ).

https://en.wikipedia.org/wiki/Spanair_Flight_5022
 
Holy Smokes!! That MD-82 was a flying disaster just waiting to happen... and it did. They MEL'd and band-aided that plane right into the ground. Ice packs to cool a sensor prior to pulling the fuse? Wiring the clamshell reverser shut although it apparently activated during take-off? Unhooking de-ice temp sensors? People who know the MD-80 airframe know that thing needs all the help it can get and if ice is encountered then you pray for a very experienced crew. And then the pilots forgot to set the flaps? Where do they get these guys?

I think I'm going to take the car on vacation this summer. Although, I am going to Berlin to watch the Atlanta Falcons whip up on the Indianapolis Colts at the Olympic Stadium this November. wooohooo.
 
FowVay said:
Holy Smokes!! That MD-82 was a flying disaster just waiting to happen... and it did. They MEL'd and band-aided that plane right into the ground. Ice packs to cool a sensor prior to pulling the fuse? Wiring the clamshell reverser shut although it apparently activated during take-off? Unhooking de-ice temp sensors? People who know the MD-80 airframe know that thing needs all the help it can get and if ice is encountered then you pray for a very experienced crew. And then the pilots forgot to set the flaps? Where do they get these guys?

I think I'm going to take the car on vacation this summer. Although, I am going to Berlin to watch the Atlanta Falcons whip up on the Indianapolis Colts at the Olympic Stadium this November. wooohooo.
Click to expand...
They also missed the flaps on the checklist.

Even though the A320 is advanced ( take off configuration warning that has to work or we don’t take off ) , I have my own , silent acronym I do just before lining up to make sure we didn’t miss anything.
 
Dborch41 said:
This is a very good video that gets into the weeds about the systems of interest on the 787. No speculation, just information. Definitely worth a watch.
Click to expand...
I actually liked the part at the end where he was positioning the planes around the field. That seems like a pretty good job for someone who could never get a medical clearance for an ATP.
 
Astro14 said:
The more I examine the video, and the more I look at the airplane itself, the more I lean towards a dual engine power loss.

Perhaps flameout, perhaps not, but either way, it looks to have affected both engines.
Click to expand...
That sure is what it looks like.
The question is why?
Crew errors, FOD, fuel or something not seen before generic to the type?
 
slo town said:
When I look at this video (and, yes, know it's an A350), the complexity of a modern airliner makes my jaw drop. It seems to me these magnificent flying machines would require a team of "brain surgeons" to keep them airworthy.

Scott

Click to expand...

Not so sure about that.
I think that an earlier jet airliner would be far more complex to operate for the flight crew and the techs.
Current types provide a lot of help to each.
A 707 or a DC-8, not so much.
 
fdcg27 said:
Not so sure about that.
I think that an earlier jet airliner would be far more complex to operate for the flight crew and the techs.
Current types provide a lot of help to each.
A 707 or a DC-8, not so much.
Click to expand...

In terms of the crew in routine operation, sure. The automation helps. But there’s also computer menus where the pilots have to know how to navigate. I have enough issues going through a Tesla touchscreen, but the pilots have a lot of stuff.

And under the hood, there’s a lot more complexity because of all the automation. Millions of lines of software. Even the engines have a control computing unit.

https://www.collinsaerospace.com/wh...actuation/electronic-engine-controllers-fadec
 
y_p_w said:
In terms of the crew in routine operation, sure. The automation helps. But there’s also computer menus where the pilots have to know how to navigate. I have enough issues going through a Tesla touchscreen, but the pilots have a lot of stuff.

And under the hood, there’s a lot more complexity because of all the automation. Millions of lines of software. Even the engines have a control computing unit.

https://www.collinsaerospace.com/wh...actuation/electronic-engine-controllers-fadec
Click to expand...

Off topic but I recall hearing when the newest Ford GT came out, that it had (has) more lines of code than a 787. Crazy.
 
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