Air India 787 crashes on take off 1

[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.

 

[Roga50]

The counter rollover bugs mentioned just shock me. I work in lifecycle maintenance (bug fixes) for enterprise-level networking hardware and we have had similar bugs in our code, over the years. We used to have our equipment starting acting "strangely" and even crashing if it was not rebooted after more than about 200 days. Took a few years to find all of the places we needed to fix for that.

There are definitely ways to address this kind of thing and mitigate the problems it causes. (when adding to or incrementing a counter, keep the "previous" value and then compare it to the new value to make sure you didn't inadvertently go backwards [or worse, go negative, because you have a signed vs unsigned datatype issue]).

I would expect that life-safety systems in aircraft would be heavily code-reviewed and tested to address this type of thing.

There's always one more bug... But it's a bit more serious when the bug can kill people.

 

[Alistair_Heaton]

"I would expect that life-safety systems in aircraft would be heavily code-reviewed and tested to address this type of thing."

I suggest you read the threads about the 737 MAX.

 

[TugboatEng]

Maybe we shouldn't assume the code engineers are always more talented than the design engineers? The team that certified the 737 did a remarkable job certifying a type that is still viable 58 years later.

Meanwhile, the 787 certification team missed major flaws that are arising only 14 years later.

 

[Alistair_Heaton]

It's a different company and procedure that certified both.

737 was external, 787 internal.

Saying that FBW is a completely different ball game to the old analog systems of what you see is what you get. The certification criteria for FBW isn't mature yet. And the goal posts keep moving.

Btw the c series gets power resets galore for various reasons. I believe there is a timed hard reset required. A hard reset is when power umbilicals removing the earth is also done and then it's left for 5 mins. Quite if that's documented or if it's our technicians SOP I have no clue.

If you don't remove the earth, faults in the electrical system won't clear. Unofficially I refer to it as hard with the earth gone. And soft without removing it.

 

[cherryg]

One grim fact with the take-off is even after using the 3km approx. runway, the plane just managed to take off. The flying dust in the video, shows how close this plane was in reaching dirt.

 

[Alistair_Heaton]

It's very rare we use max thrust for departure. Here is the ins and outs of it.

Reduced Thrust Takeoff | SKYbrary Aviation Safety

A reduced thrust takeoff is one that is accomplished utilising less thrust than the engines are capable of producing.

skybrary.aero

 

[Brian Malone]

Wow, incorrect FADEC input can put even an experienced crew in a pinch if they are not fully paying attention.

 

[XR250]

Interesting. I would have thought that would max them out so they could have more runway available for an abort before they reach V1.

 

[Alistair_Heaton]

Wow, incorrect FADEC input can put even an experienced crew in a pinch if they are not fully paying attention.

Yep they are mid development of a system that independently checks your position and performance mid takeoff run and triggers a master warning to reject if it's not going to work.

 

[LittleInch]

One grim fact with the take-off is even after using the 3km approx. runway, the plane just managed to take off. The flying dust in the video, shows how close this plane was in reaching dirt.

I think there is some dispute about that. The videos and ADSB data seem to show it lifted off in plenty of time, just yawed a bit to the right and hence the jet blast picked up some dust on the ground to the left hand side / wing tip vortices as it isn't that wide a runway and it didn't look like it stayed dead on the centreline but drifted left a bit. The reported air speed or even ground speed was in excess of min take off speed.

We will need to see the results and data from the FDR and other information available to the investigators, but beware of assuming things that may not apply or be correct.

Companies save bits of fuel everywhere they can and if there is room on the runway they use it. The 787 has a bit of a reputation for taking its time to get airborne, but that then can help it in cruise when it has less drag, but lower lift at lower velocities.

 

[Alistair_Heaton]

It's engine wear not just fuel I believe for TO thrust. There is a factor applied.

The performance app optimises the settings to give the most cost effective.

Climb thrust is another story.

Then there is noise abatement restricts which change when you change the power and when it accelerates

 

[IRstuff]

Flying from John Wayne airport used to involve what felt like full power TO, followed a levelling off and reduction of thrust; something to do with noise abatement over rich peoples' houses.

 

[Milliontown]

Flying from John Wayne airport used to involve what felt like full power TO, followed a levelling off and reduction of thrust; something to do with noise abatement over rich peoples' houses.

I've done it many times, it's definitely a ride.

 

[LittleInch]

Try Sumburgh. They used to put the turbo props into reverse and back up the runway to the very end when they were a full plane then go full throttle holding it on the brakes before catapulting down the runway. Get it wrong and you're in the water...

The opposite was Changi in singapore in an underpowered soviet piece of garbage which I swear finally lifted off just as the red lights went past and just clawed its way into the air. Convinced I was going to be in the water on that take off. And it wasn't even full. The sodding thing had the acceleration of a moped.

 

[Alistair_Heaton]

Being an ex Highland Airways pilot I know Sumburgh well, the pointing at the lighthouse and then turning 1 Nm to land used to freq some out.

When they extended the runway before my time it was a sigh of relief by alot.

Here is a good description of what we do....

Noise Abatement Procedures set out by the International Civil Aviation Organisation and low flying aircraft on departure from Heathrow

On departure there are two noise abatement procedures where a stepped departure climb is being used. They are called “NADP 1” and “NADP 2” (Noise Abatement Departure Procedure). 1 is used where there are noise

www.teddingtonactiongroup.com

Some places like Zurich there are microphones all over the place and you will get an email the next day to justify coming off them.

 

[1503-44]

ADSB shows they reached 575 to 625 ft altitude over the end of the runway.