Thanks Min- But that isn't exactley right either!!

V1 is usually the minimum GO speed, particularly on a long runway. It's entirely possible that, if a truley unflyable condition became evident at Vr, that an RTO COULD successfully be carried out in a fair proportion of takeoffs.

If what has been said in that he pulled back and nothing happened what was he supposed to do keep the power on and crash at great speed probably killing all or knowing he had a long runway attempt and manage a stop.....tyers as has been said have fusible plugs for the reason to prevent tyres blowing out. There has been much tosh spoken on this thread from some people who know nothing about aviation....listen to those that do!!!! Lets wait for the official reason and real facts come out shall we. As an FE if the driver in front of me pulled back, big clunk and no attempt to get airbourne and we stopped in time I would be buying him more beer than he could drink for some considerable time.

Only if you're fairly light - I wouldn't want to try it with a heavy TOW.

Minimum Wage : The difference between V1 and Vr on a 777 can be very minute. In fact they can and are (dependent on company performance criteria) be the same speed.

Sounds to me to be a normal reject at high speed in a heavy 777. I would expect my 777 after a high speed heavy reject would also melt the fuse plugs. I would be suprised if they didn't!

Nor would you except as a last resort. If there is any truth, however, to the speculation that the aircraft wouldn't rotate, you'd have a fighting chance of staying on the paved surface in a fair number of circumstances. We don't actually go to field-limiting conditions that often, and assumed temperature method does involve extra saftey margins over and above the normal regulatory net limits.

Still, if he's got to Vr, not been able to make it fly, and reacted quickley enough to stop by the end, he's done an outstanding job.

All speculation at this time, however.

Wasn't there a comment from the Crew on the AF RTO about control problems as well (heavy to rotate?)

So far the only one that's implying a stop after V1 is SKMARZ and he heard a rumour; it could well be that his rumour just mixed up the AF at Lagos with this one. After all this is a rumour network but it is a waste of energy to spend the next 10 pages reading speculation on a rumour that never happened and probably is going to be a copy/paste of the AF-thread. Anyone else could confirm this theory?

The 777 OPT does not do a Balanced Field calculation. It does an optimized or improved climb calculation depending on where it is limited. I don't know if the Kiwis have an EFB or if they use RTOW charts. In any case, it very possibly was not a balanced field calcultion so for anyone to suggest that an abort above V1 is not viable is BS. If this is too confusing for you, good. Go to the spotters forum.

They had an incident, no one was hurt, and the a/c can be used again. Good result!!! That's all we know. Pronouncements by wannabes don't further our understanding.

might be of interest

YouTube - Boeing 777 rejected take off (RTO)

Jetjockey
 

JetJockey beat me to it. The RTO test from the series 'Making of the 777' was one of the most impressive and spectactular events in a film full of impressive engineering. I believe they called it 'The Big One', because they knew they would damage the aeroplane, it was dangerous and Cashman was in half a mind not to do it. The test was made even more harsh because they had to rate the P&Ws at something like 104% or even 106% to allow for the Trent engine variants.

From an engineering point of view, in spite of knowing all about carbon fibre brakes, it is still an awesome sight to see how materials can stay together at the molecular level, when subject to stresses like that.

Roger.

...maybe?
 

more of the same?
Air France rejected T/O in Lagos.
Boeing has reported around 15 cases of problem with A/T engagement due to operational misstep by the crew...
Hope not.

I'm fully aware that limiting RTOs may produce deflations and indeed fires, thankyou to you all.

Information quoted from Boeing's Take Off Saftey Training Aid (TOSTA). :rolleyes:

Prima Facie - on the face of it. Sufficient to require further investigation. :hmm:

That means that it's a bit rich to say "12 tyre bursts are not important" :hmm:

On the face of it,no evidence that 12 tires DID "Burst" other than usual media hyperbole. Very small amount of investigation seems to confirm this.

Every reason to believe a standard, well handled RTO resulting in predictable, by-design tire deflation after fuse-plug melt.

Umm, Checkboard - jetjockey737 and Wizofoz beat me to it. Watch the video. As I said before, this is the expected result. The tyres didn't "burst", they deflated because the fuse plugs did the job they are designed to do.

Thanks jetjockey737 - that's the DVD I watched - and I agree landroger, it's a great piece of work.

The unanswered question here is the reason for the RTO.

I want you to handle any investigation I am involved in, Wiz. :ok:

If it was high enough energy to either burst or deflate 12 tyres it would normally be classified as "high" or even "severe" risk in a safety analysis.

Yes in the video they did. You have video of this event?

Not saying it didn't happen, just saying you don't know it did happen.

The fusible plugs are placed on the rims, near the brake assembly in order to react to heat generated from the brake pack. If the heat in the tyre is not generated from the brake pack (i.e. it is generated in the tyre itself during long taxi operation for instance) then the fusible plugs more often than not won't operate (as rubber is a poor conductor of heat, sufficient heat doesn't reach the plug) and the tyre will burst.

Checkboard - I'd rather believe a 777 driver who has explicitly stated his experiences in an a situation that under heavy braking both sets of trolleys deflated because the fuse plugs blew. Whilst this may be unverified, I'll go with it.

I guess what I am saying here is that the tyre deflation (NOT "burst") is secondary to the reason for the RTO. If it was an RTO at MTOW, it's just going to happen. It's part of the rationale for the certification for the airframe.

I landed a A340-600 last week (10 tons below MLW of 259 tons) after a Green Sys Hyd failure leading to Alternate braking. Even trying to brake gently (a little more difficult with Alternate Braking) and using all 15500ft of runway led to several brakes above 650 deg. A MTOW RTO will easily melt the fuse fuseplugs on any airliner certified under current regs.

taxi clear
 

Not making any grand pronouncements here - just a question. Air New zealand reported that the a/c taxied clear. Was that a good idea from an engineering point of view, running on rims must cause extra damage musn't it ? To say nothing of shaking up the pax even more than they already would be.

A few years ago I had a main-gear tyre that disintegrated shortly before V1.

All my training told me to continue the take-off.

If I rejected at this speed, we would only have a fraction of the full length of the runway in which to stop and the braking effort would be reduced due to the damaged tyre.

If we continued and got airborne, we could leave the gear down, complete any required checklists, reduce our landing weight to a minimum and then land on the full length with the fire crews in attendance.

All these thoughts went through my mind in a short time-frame.

While I was pondering this ‘received wisdom’, the aircraft was shaking and vibrating so much that the instruments were unreadable.

We were drifting to the right of the runway, towards scrub and rough ground.

There was still quite a lot of runway remaining ahead.

What did I do?

Did I make the right decision?

What did I learn?

Answers will be posted in a few minutes, so stay tuned!

In the meantime, all the ‘Monday morning quarterbacks’ can tell me what I should have done!

Eckhard - are you sure you weren't landing at YYZ?


I'll get my coat.... :}