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EK407 Tailstrike @ ML

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EK407 Tailstrike @ ML

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Old 30th Apr 2009, 11:01
  #701 (permalink)  
 
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One question here, how many similar events have occured using paper calculations as opposed to laptops? 2 events using laptops spring straight to mind, this and MK, none from paper.

I should add that I've never used a laptop for TO calcs only ACARs and far too many years of performance manuals.
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Old 30th Apr 2009, 11:05
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One doesn't need a laptop plus an Fmc to work out that EW+Fuel+Pax+Freight=TOW.

If you do then I suggest you shouldn't be in the job!
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Old 30th Apr 2009, 11:17
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Simple GIGO. The EK procedure is designed to try and trap the errors via Gross Error Checks and a final cross check of the lap top Green Dot, Minimum Clean speed and the Minimum Clean Speed in the FMS.

At 360 tons GD would have been about 265 ish, at 260 tons 30 kts or so less. If they had followed the mandated procedure they would have caught the error. However even if they hadn't followed the procedure I would hope most pilots would have the awareness to recognise that a 360 ton A345 needs Flap 3 not Flap 1, 170kts ish to rotate and 265 kts for minimum clean with a flex somewhere in the 30s not 74. That a crew did not know that is a concern and the lack of awareness maybe points to a complacent rather than questioning culture. Also reading the report I wonder how many of us would have selected TOGA having reached the 900m to go markers without any obvious signs of getting airborne.

Earlier someone questioned the level of thrust reduction. The max reduction from Flex is around 25% depending on the airport so they would have had probably 20% less thrust than expected during the take off roll.

Some may think I am harsh but I feel sorry for the guys on a personal level but not professionally.
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Old 30th Apr 2009, 12:16
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EkwhistleBlower,
There but for the grace of God go you or I.
A professional crew that makes a fundamental error = contributing factors.
None of us are immune fom error.
And by the way, the error in your post is that at 360 tonnes the flex off Rwy 16 in Mel is 45 - not in the 30's.
So much for your awareness - now I'm concerned for you!
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Old 30th Apr 2009, 16:49
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ekwhistleblower

needs Flap 3 not Flap 1,
Not necessarily so. I'd be interested to see the figures for that.

I would hope most pilots would have the awareness to recognise
Depends what you've been flying recently and on what sectors you've been flying in the a/c and how tired you are. With the mix of types and the ability to be legal on the 340 but not fly the specific "variant" for months that doesn't hold true.

Also reading the report I wonder how many of us would have selected TOGA having reached the 900m to go markers without any obvious signs of getting airborne.
With the introduction of RAAS, I'll be using that as a trigger if the speed trend isn't where I think it should be.
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Old 30th Apr 2009, 21:46
  #706 (permalink)  
 
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Is there no system on the A330/40 to make a reasonable calculation of aircraft weight/balance based on oleo compression? I'm not familiar with airbus aircraft but they seem to do just about everything else!
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Old 1st May 2009, 03:00
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@ No Land 3 - thanks for the answer to my post - much appreciated.
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Old 1st May 2009, 04:00
  #708 (permalink)  
 
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900m to go markers?

EKwhistleblower,
Also reading the report I wonder how many of us would have selected TOGA having reached the 900m to go markers without any obvious signs of getting airborne.
There are no such markers on the runway at YMML. Where are they?

Putting it simply, if my car tried pulling away from traffic lights using 30% less power, it would be noticed immediately.
Well, if you customarily slammed your foot to the floor on the green light, you probably would. But if you just cruised off from the lights like most, I'm not so sure... I would just put my foot down a bit more, if I did notice.
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Old 1st May 2009, 05:16
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I'm not so sure... I would just put my foot down a bit more, if I did notice.
That's my point though - 'User Input' - would the pilot not increase power accordingly during the take-off when he noticed there wasn't the required power? Would an experienced pilot not have a 'feel' for a take-off (ie. sluggish performance, etc) regardless of what the instruments were saying?
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Old 1st May 2009, 06:41
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fred_the_red,

Taking off in a large jet, using balanced field length figures for every departure, is not the same as taking off in a light aircraft. At high gross weights all take-offs seem sluggish to start with. Then the acceleration picks up & you rotate with the end of the runway rushing towards you. Sometimes I wonder how we would ever stop from V1 in the runway remaining at that point, but you have to trust the figures.

If you look at the initial tailstrike location in the diagram in the accident preliminary report & allow for the 9 second time interval between initiating the rotate & first tail contact that is also in the report, the rotate position on the runway was about right for a normal take-off.

The extra 100 tonnes over the weight used for the calculations would have some effect on the time to reach rotate speed, but I don't think it would have been that significant. The big problem was that the speed attained was some 20kts short of what was required for the aircraft to fly at the weight it actually was.

The crew would have had very little indication that things were not right until they rotated & the aircraft did not fly. The aircraft 'always' flys when you rotate at Vr & the crew would have been wondering wtf was wrong. With the end of the runway rapidly approaching & not knowing what the problem was, the captain's first reaction was to command more pitch in an attempt to get the thing in the air. When that didn't work the only other option was to push the thrust right up & hope for the best.

When they finally staggered into the air I would be willing to bet that they still didn't know why the aircraft didn't want to fly at Vr. They may have thought of an incorrect flap setting, a screw up by the loaders & extra weight not accounted for in the figures or a number of other possibilities. It would have only been at some stage during this trouble shooting discussion that they would have realised what the problem was.

It is just extremely lucky that it was on 16 at Melbourne & they had the overrun & relatively obstacle free departure path that they had, or the result could have been vastly different.
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Old 1st May 2009, 09:28
  #711 (permalink)  
 
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It appears the thread could now be renamed "EK407 Accident at MEL".

I am surprised the Preliminary Report did not make reference to the crews
A330-200 experience or highlight the 37 tonne overweight landing.

In my view there was little in the report to reflect the time taken to table it.
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Old 1st May 2009, 10:17
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Hi Oakape - thanks for the reply

Another, maybe overly simple idea (for a non-pilot), why not engage full throttle for all take-offs and adjust throttle back when safely airborne, either manually or via automated flight systems? I'll duck for cover now .
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Old 1st May 2009, 11:08
  #713 (permalink)  
 
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FULL thrust

fred_the_red. When Max thrust is used for take-off that thrust is only used until shortly after take-off when it is reduced to Climb Thrust. Reduced thrust is used when possible to enhance engine life. The turbine section is like an elephant, it has an enduring memory and every time a temperature higher than a previous one is reached it is "remembered". The cumulative effect on the turbine determines it's operational life. Reduced thrust take-off procedures are in themselves not dangerous. What can lead to an incident/accident like Emirates is a reduced thrust setting being used when not appropriate.
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Old 1st May 2009, 11:19
  #714 (permalink)  
 
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The crew would have had very little indication that things were not right until they rotated & the aircraft did not fly.
Are you sure about that ?

Surely the PNF calling out rotate at a speed that was clearly insufficient would have rung alarm bells.

I can't believe they operate any ULH revenue routes where Vr could be such a low figure.

There are definitely some serious human factors involved in this, I cannot believe fatigue does not play a part.
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Old 1st May 2009, 12:43
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With the end of the runway rapidly approaching & not knowing what the problem was, the captain's first reaction was to command more pitch in an attempt to get the thing in the air.
Wouldn't increasing the pitch aggravate the situation even more, ie, cause airspeed to decay? Would have thought the first reaction would be to apply full throttle if the aircraft didn't lift off at Vr.

Anyway, it's easy for us to say all this in hindsight, but the guys upfront only had seconds to decide what to do. I'm very much appreciative of their handling of the abnormal take-off and so too are my grandparents who live in Keilor not too far off from the runway 16 centreline.
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Old 1st May 2009, 12:53
  #716 (permalink)  
 
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The extra 100 tonnes over the weight used for the calculations would have some effect on the time to reach rotate speed, but I don't think it would have been that significant.
With the incorrect TOW entered into the laptop, the computed VR is also incorrect, for starters, so the aircraft will not become airborne properly when that incorrect VR is reached. (ie: a higher than normal body-angle is required or a tail-strike occurs during)

Since the thrust is appropriate for the wrong weight, the aircraft will not even accelerate correctly to that incorrect VR, let alone the correct VR.

Incorrect VR is reached further down the runway than computed. And in this case, even the correct VR was not reached on the runway.

That's my point though - 'User Input' - would the pilot not increase power accordingly during the take-off when he noticed there wasn't the required power? Would an experienced pilot not have a 'feel' for a take-off (ie. sluggish performance, etc) regardless of what the instruments were saying?
The pilots DID increase power. The question is (or was) when.

In your car, you can determine normal acceleration quite easily. Engine noise and visual cues from being a foot above the ground are easy to judge. Even throttle position with your foot can help. The Airbus throttles go to the same position EVERY time (except TOGA takeoffs).

In an airliner, with eye-height that far above the ground, acceleration oftens looks insignificant. Then there's the added factor of night-time conditions which can reduce the visual cues to a series of points of light.

As for noticing the "feel", pilots are not jedi knights and The Force does not help them. Flying the same type on the same route, yes, you could reasonably expect a pilot to notice this sort of event early on.

But with the variations in conditions experienced on THREE different types of Airbus with many different weight ranges, runway lengths, airport elevations and temperature extremes, you can reasonably question whether or not the "feel" can be relied upon.

why not engage full throttle for all take-offs and adjust throttle back when safely airborne, either manually or via automated flight systems? I'll duck for cover now
If you're ducking for cover, you must have some idea what sort of suggestion you're making but you make it anyway. I think it's been covered by now that the flex procedure is quite normal and not, in itself, a threat to safety. In the right conditions, this accident could've also happpened using rated thrust if a critical error had been made during performance calculations.
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Old 1st May 2009, 14:43
  #717 (permalink)  
 
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With this preliminary information now available, it seems to me that the airline's claims in the media of having safety as their highest priority are decidedly hollow. Given that the crew involved have been gassed by their employer, how much of a safety culture do they actually expect going forward? I can see many more ASRs going in the bin with a culture like that in play.

JMHO
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Old 1st May 2009, 15:18
  #718 (permalink)  
 
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Originally Posted by B772
I am surprised the Preliminary Report did not make reference to the crews A330-200 experience
I have heard some interesting stuff about this, but could someone more knowledgeable answer:

What aircraft were they rated on and when (330/340)?
What sort of ratio of time spent on each type?

Obviously what I'm getting at is, could it be that they were experienced on the 330 and entered a 330 kind of weight when in a 340, and could training/experience of the 340 have had anything to do with this error? Are we back to Kegworth (differences course)?

Apols if off target, but this thinking came from an EK driver.
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Old 1st May 2009, 15:26
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Ex Cargo Clown,
Surely the PNF calling out rotate at a speed that was clearly insufficient would have rung alarm bells.
The PNF called rotate at the bugged Vr, where he was supposed to. This call is a backup call & the PF is required to commence rotation at the bugged Vr, whether the call is made or not. Therefore, he/she is required to monitor the speed during the take-off as well as the PNF. I put it to you that the speed wasn't clearly insufficient, as there are a number of occasions where the speeds are discussed prior to the aircraft commencing the take-off roll, & the crew obviously thought that they were sufficient at these points in time! They are only clearly insufficient with 20/20 hindsight. However, the fact that 4 pilots did not feel that the v-speeds that were generated were somewhat low is something that should be looked at. Many things could lead to this, including cross-type qualification, distraction, inadequate cross check & fatique, to name just a few. To try & pin down a reason at this stage would be pure speculation.

There are definitely some serious human factors involved in this, I cannot believe fatigue does not play a part.
Of course there are human factors involved in this error. I would put it to you that this part of the accident chain is purely human factors related, as opposed to a technical issue.

JulieFlyGal,

Wouldn't increasing the pitch aggravate the situation even more, ie, cause airspeed to decay? Would have thought the first reaction would be to apply full throttle if the aircraft didn't lift off at Vr.
This is a very good question. From the preliminary report the aircraft started to rotate at 152 kts. 8 seconds later the aircraft was still accelerating as the speed was 156 kts when the tail contacted the runway. A slow acceleration for sure, but still an acceleration. However, from this point, the aircraft did not get above 157 kts until after it was airborne. So even though maximum thrust was applied, the aircraft did not continue to accelerate - possibly due to excessive pitch, or due to the extra drag from the tail scrapes & the main gear rolling over grass rather than paved runway, or a combination of both. Perhaps someone with a good knowledge of the theory of flight could shed some more light on this.

YoDawg,

Since the thrust is appropriate for the wrong weight, the aircraft will not even accelerate correctly to that incorrect VR
I agree, but still feel that the difference to the physical position on the runway that Vr was reached wouldn't have been large enough to have a visual impact on the pilots during the take-off roll. Particularly at night & if they hadn't flown this sector off rwy 16 at Melbourne for a while. My reasoning for this is based on the position on the diagram in the preliminary report that shows the location of the start of the first tail strike & guessing how far before this point the crew commenced the rotation, given the fact that the rotation was commenced 9 seconds before this point.

Perhaps some of the geniuses on this forum could compute the distance from the commencement of the take-off roll to the rotate point, using the figures that the crew used & also using the correct figures. I would be interested to see what the difference in distance would be.
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Old 1st May 2009, 16:25
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Originally Posted by HundredPercentPlease
Obviously what I'm getting at is, could it be that they were experienced on the 330 and entered a 330 kind of weight when in a 340, and could training/experience of the 340 have had anything to do with this error?
Virtually similar cockpit but so much different aircraft regarding the weights. One guy can enter 262 tonnes and feel very confident as it is pretty close to MTOW for the 340-300 he may have flown the week before ...

Flying so different aircrafts but from so similar cockpits must be part of the problem.
Add up fatigue and that's when you turn complacent.
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