Not knowing what's factual vs speculation

what's the possibility that the event happened on taxi out and that the plane was tugged back to a stand and disconected and nothing happened between a tug and the plane to cause the event?

:= Read more carefully. He tried to take off from a runway near the airport...

Would not discount it completely, but that would sound too simple. During my time in the fine land of the sand, I have learnt to expect the most absurd, illogical and unlikely explanation to be the real one...

- skid marks?

andrasz
What is it about
that you don't understand? ;)

Do you understand why I put the :E in there?

In case you were unsure, I was poking fun at the "art" of journalism there.

I did indeed read the whole article.

Cheers.

That -115b puts out a massive amount of thrust. My guess from the picture, engine or engines running, tug driver is in a sharp turn snaps tow bar, aircraft rolls into tug, tug driver ****'s his pants, women and children scream.

Oh those skid marks

Lonewolf_50,

...runway...near...airport...

I was just topping your :E, take it easy :)

Aha, well played, I guess that went over me :O at about FL 250. :}

MELDreamer’s input to the story says that the engine went to full power (post #13).

Many years ago, my airline had that once during engine start on a DC-10. Throttle cable had been moved and misrouted during maintenance, so that the inner cable was in a pulled state at the main engine control end, while the thrust lever on the flight deck was in the normal idle position. One of the rpm's, I think N1, was above 80% and rising before the fuel cut-off was effective, if my memory serves me right. Hair-raising experience, as the Flight Engineer told me when they came back into the office. I think I still remember which F/E.

Back to JED. With brakes off, and given a similar malfunction, a 777 loaded for this short trip might begin to advance against the tug and then break out of line to the side where the tug isn’t. Towbar shear pins snap; the a/c moves further forward. By the time the flight deck is aware that they not only have a runaway engine, but a runaway airplane as well, the tug is hit by the engine inlet. The skid marks on the ramp near the inlet may have to do with the uncommanded turn induced by differential thrust and/or the angle of the nose wheel that was steered by the towbar until shear pin break-off.

So maybe, if you accept the uncommanded accelerating engine, the rest does not appear to be excessively wild phantasy?

A similar incident happened to a 777 years ago, in that particular case the thrust levers were not at idle they had been moved (after all checklists/flows were complete) to rectify and unrelated maintenance issue, crew failed to notice the position (human factors) Eng 2 started first, reached idle and rapidly accelerated to a high thrust, broke the tow bar and the A/C moved forward and yawed left instantly due to the asymmetric thrust thereby missing the tug with the nose gear, also the tug now accelerated towards the aircraft or engine. The crew were able to stop the aircraft before contacting the tug, had it been powered by GE90-115 maybe they would have hit the tug.

My guess is its a similar incident, and questions asked as to the reason for the thrust increase, thrust lever position or EEC fault?

Tug jump
 

And that was.... Hmmm ..an A6 aircraft I think... But not allowed to post operators are we ... Didnt get any nice pics on pprune but.

Theory
 

Based on the photo in post 5.

There appear to be 3 sets of skid marks visible in the photo:
1: opposed cresents just in front of the engine;
2: large radius arc splitting to 2 tracks in the foreground;
3: (possibly) behind the inboard main gear wheels.

Marks #1 from tug which doesn't move much but is rotated ~90° right during the "manoeuvre".

Mark #2 traces the arc of the nose gear, radius = nose gear to tug centre of rotation, as the a/c rotates to its left. Track splits into two when the shear pin lets go and gear steers left.

Mark #3 caused when crew apply brake (parking brake?) and also indicates a/c rotation to its left.

So, the ballet started with the tug in position indicated by marks #1 and the a/c further back and with a heading maybe +30° to +90° compared to its final heading. Towbar probably close to a/c axis.

No.2 engine goes to high power. A/c brakes are off. Tug brakes are on. No.1 engine may not have started yet or is spooling up or at idle. Monster resulting torque is enough to skid the nose gear to the a/c's left. Shear pin goes when the nose gear steering angle limit is reached. Crew apply brakes. Tug driver ****s his pants. Tug contacts inlet and rattles around against it until No.2 is shut down.

Name and Blame Saudi style
 

Punishments? Throttle hand excisions? Local laws are known to be harsh and nonsensical :))

Nothing comes to mind with a FADEC runaway to me. Everything is so redundant.

Yea I was trying to be kind, I seriously doubt a engine fault.

To be clear, I don't know anything about the 777!

But I do know that, in the 737NG if the autothrottle is armed during pre-flight checks, one only has to touch either of the TOGA switches and both engine thrust levers will immediately advance to takeoff power.

Thats why we don't arm the autothrottle until approaching the departure runway!

If the 777 system is anything like the 737 then . . . . . .:eek:

I'd imagine the 777 is similar to the 744 you need flaps for the TOGA switches to be armed.

Zero chance that it happened like that.

Read SMOC posting, the reason is known, the cause isn't.

Nothing a bit of speed tape couldn't sort!!

A simple explanation might be an attempt to taxi with the tug still attached. Has happened a fair few times in the history of aviation and probably will in the future too. ATC clearance received, headset disconnected, bit of distraction, easy to do...

Even a big tug would be no match for two 115Bs.