Emirates A345 tail strike

[NickN]

I'd hate to see the fuel bill for a low altitude depressurized ferry from Australia to France!

I'm surprised the pilots didn't detect that they weren't approaching Vr speed in the required time and perform a RTO. Would a pilot know their aircraft wasn't accelerating appropriately and know something was wrong? After using up two thirds of YMML's runway and still not being anywhere near the required speed would ring alarm bells for a pilot wouldn't it?

[Owen H]

Its a tough one! He would notice at some point, but by the time he does it might be too late to do anything other than continue anyway.

Values like V1 have no meaning when they are calculated for the incorrect weight/thrust.

[Mike W]

Maybe they should just "junk it". (I'm joking in case anyone takes exception)

I'm sure EK would prefer to take the insurance on a 345 and move on. (Not joking)

[NickN]

I understand that after V1 the only decision is to go, but what happens in an instance like this when there isn't enough thrust to get off the ground in time?

Also, even though the FMC selected the incorrect thrust due to incorrect weight input, can the pilot apply any more thrust manually by pushing the thrust levers further forward? Or is full thrust (i.e. levers fully forward) the de-rated selection as made by the FMC?

I hope that made sense !

[Andrew McLaughlin]

Originally Posted by NickN

I understand that after V1 the only decision is to go, but what happens in an instance like this when there isn't enough thrust to get off the ground in time?

What happens is what happened in Melbourne....or much worse!

Originally Posted by NickN

Also, even though the FMC selected the incorrect thrust due to incorrect weight input, can the pilot apply any more thrust manually by pushing the thrust levers further forward? Or is full thrust (i.e. levers fully forward) the de-rated selection as made by the FMC?

The pilots can override by hitting the TOGA switch.

[NickN]

Would they not have had the sense to take advantage of the TOGA switch when their backside was scraping the paint at the end of the runway?

Given the fact they only just cleared a 2.7m fence half a kilometre from the end of the runway it appears as if no further action was taken. I would have been hittin' that switch like a madman to get off the ground quickly!

[Owen H]

Theoretically a pilot would hit the switch and push the thrust levers fully forward to get maximum thrust.

That said, there are enough similar incidents that have shown the pilots are too busy just trying to keep the aircraft upright than to think of hitting TOGA.

[NickN]

Thats true Owen, I suppose so much is happening during takeoff that sometimes the most simple things get overlooked.

Out of curiosity, what procedures are in place for checking and then re-checking the weights and inputs into the FMC to avoid incidents where incorrect weights affect thrust settings? I would have assumed there was a system for checking everything before actually flying.

[Chris Griffiths]

Originally Posted by NickN

Would they not have had the sense to take advantage of the TOGA switch when their backside was scraping the paint at the end of the runway?

Given the fact they only just cleared a 2.7m fence half a kilometre from the end of the runway it appears as if no further action was taken. I would have been hittin' that switch like a madman to get off the ground quickly!

It is only a TOGA button, not a miracle anti gravity device, you cannot instantly transform a couple of hundred tons of lumbering truck into a rocket ship. You need to be aware enough of your situation to press it and take other action soon enough, it appears for whatever reason this crew were not in that position.

[Ken K]

Originally Posted by NickN

I'm surprised the pilots didn't detect that they weren't approaching Vr speed in the required time and perform a RTO. Would a pilot know their aircraft wasn't accelerating appropriately and know something was wrong? After using up two thirds of YMML's runway and still not being anywhere near the required speed would ring alarm bells for a pilot wouldn't it?

What Owen said about V1 going out of the window when calculated for incorrect thrust is correct. Taking an inadequate thrust example, as V1 would occur at a point further down the runway, you can neither guarantee there is enough runway to stop in the runway remaining in a stop scenario from V1, nor that continuing from V1 with engine out will result in attaining a height of 35ft by the end of the runway.

Bear in mind too that in the high-speed portion of the takeoff (above 100kt for the A330/340), a pilot should be go-minded. While I can't comment on Emirates policy for rejected takeoffs on their A330/340, here's another carrier's policy for the A330:

Between 100kt and V1, reject only for:
ENGINE FIRE
APU FIRE
ENG FAIL
ENG OIL LO PRES
ENG REV UNLOCKED (reverser unlocked)
CONFIG Warning
SIDESTICK FAULT
L+R ELV FAULT (elevator fault)
Severe damage
Tyre failure below v1-20kt

Continue if visibility lost

Andrew, the Airbuses don't actually have a TOGA switch. A derate is deleted by moving the throttle levers from the FLX/MCT detent (takeoff setting when using a derate) to the TOGA position. Pushing TO/GA to remove a derate doesn't work on the B744 either. It can only be used to remove a derate after lift-off and before the reference thrust limit changes to climb.