Air Atlanta Cargo incident Sharjah 07/11/04
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I think Mutt is alluding to the probability of stopping in time. If you reject at V1 on a field length limited runway you're looking at a 50:50 chance of ending up in the overrun even if you do everything right.
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Not accusing anyone of this, so don't start! 
But I heard they tried rejecting just after V1. Anybody else hear that?
BTW:
The damage has ben caused by piled up sand. Last time I checked sand is moved very easily by wind and/or jet blast. To keep the area perfectly or even relatively clear would require a hell of a lot of round the clock work - expense. Just my opinion.
But I heard they tried rejecting just after V1. Anybody else hear that?BTW:
how is it that terrain is so rough so close to the runway ?
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Thanks for the offer Rocca, guess that I will continue. I wasn’t referring to the AAI incident, as I have NO idea as to what happened.
But lets take your B737, pick some nice short field where you will be runway limited, does your airline account for the line-up distance? Did Boeing test the aircraft with new brakes and tires? Did Boeing test the aircraft on a perfectly calm day with ISA conditions? Did Boeing test the aircraft knowing the exact weight of the aircraft? How long does it take you to say V1?
It isn’t really a case of disregarding procedures or endangering the lives of others as you so nicely put it. I would have thought that as a professional aviator you would have appreciated the situation that your colleagues may have found themselves in, and accepted that sometimes 5hit happens!
Mutt.
But lets take your B737, pick some nice short field where you will be runway limited, does your airline account for the line-up distance? Did Boeing test the aircraft with new brakes and tires? Did Boeing test the aircraft on a perfectly calm day with ISA conditions? Did Boeing test the aircraft knowing the exact weight of the aircraft? How long does it take you to say V1?
It isn’t really a case of disregarding procedures or endangering the lives of others as you so nicely put it. I would have thought that as a professional aviator you would have appreciated the situation that your colleagues may have found themselves in, and accepted that sometimes 5hit happens!
Mutt.
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OK. By 'a reject at V1' I mean taking the first action to reject the take-off at V1. In other words shouting stop, retarding the throttles, starting to brake if autobrake is not set, all at the instant the PNF calls V1.
The 50:50 stat comes from the idea of a normal distribution, where, if you take a large group of aircraft at identical weights and speeds, some stop very well, but only a few, some go miles off the end, but only a few, whereas most cluster around a mean. The Americans call it the 'bell-shaped curve'. Assuming the testing has been done correctly when you stop in the above circumstances the mean aircraft, or gross to use the proper term, will just stop in the EDA, by the end of the stopway. This is only the average aircraft, though. 50% of aircraft will lie to the right of the mean in a normal distribution and stop in a longer distance, 50% will stop in less.
In other words, there are no safety factors built into the stop case other than the improbability of a failure at VEF that requires a stop, which, from memory, is assessed at an improbability of 1:100,000 to 1:10,000,000. This is the principal reason why most take-off briefs have a niff naff and trivia cut off at 80 kts or thereabouts and will only require a stop at high speed but below V1 for killers e.g. engine failure, fire, structural failure and sometimes a config warning.
The 50:50 stat comes from the idea of a normal distribution, where, if you take a large group of aircraft at identical weights and speeds, some stop very well, but only a few, some go miles off the end, but only a few, whereas most cluster around a mean. The Americans call it the 'bell-shaped curve'. Assuming the testing has been done correctly when you stop in the above circumstances the mean aircraft, or gross to use the proper term, will just stop in the EDA, by the end of the stopway. This is only the average aircraft, though. 50% of aircraft will lie to the right of the mean in a normal distribution and stop in a longer distance, 50% will stop in less.
In other words, there are no safety factors built into the stop case other than the improbability of a failure at VEF that requires a stop, which, from memory, is assessed at an improbability of 1:100,000 to 1:10,000,000. This is the principal reason why most take-off briefs have a niff naff and trivia cut off at 80 kts or thereabouts and will only require a stop at high speed but below V1 for killers e.g. engine failure, fire, structural failure and sometimes a config warning.
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Rocco
"You’re better off continuing." Not necessarily Sir. There are exceptions.
There have been cases, where continuing has not been the best option. Take the HS748 at Stansted a few years back. The Captain aborted, AFTER V1 and saved the day and runoff the end of the R/W. Not by the book, but saved the day, not too mention the passengers and themselves.
Not being critical of the dead, but the ones that didn't abort after V1, now let me see, The DC8 at Jeddah, over ten years ago. The AF Concord at CDG, to name 2.
Yes, I am aware 20/20 hindsight is a marvellous thing.
Until the investigation is complete on the overrun at SHJ, lets not be too critical of the crew. If the tyres had disintegrated and they aborted, even after v1? Well who knows? I would certainly rather be sitting in a burning A/C on the ground at the end of the R/W than in the air.
On the other hand, if they didn't follow the book, and it was deemed to be the wrong decision, then they will have the book thrown at them.
"You’re better off continuing." Not necessarily Sir. There are exceptions.
There have been cases, where continuing has not been the best option. Take the HS748 at Stansted a few years back. The Captain aborted, AFTER V1 and saved the day and runoff the end of the R/W. Not by the book, but saved the day, not too mention the passengers and themselves.
Not being critical of the dead, but the ones that didn't abort after V1, now let me see, The DC8 at Jeddah, over ten years ago. The AF Concord at CDG, to name 2.
Yes, I am aware 20/20 hindsight is a marvellous thing.
Until the investigation is complete on the overrun at SHJ, lets not be too critical of the crew. If the tyres had disintegrated and they aborted, even after v1? Well who knows? I would certainly rather be sitting in a burning A/C on the ground at the end of the R/W than in the air.
On the other hand, if they didn't follow the book, and it was deemed to be the wrong decision, then they will have the book thrown at them.
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I am not a pilot, so unlike Alex Whittingham, I am not going to offer my expertise on a piloting issue I am obviously not qualified to talk about. What I can offer is only what I have heard "from a reliable source".
QUOTE
The aircraft was going down the runway and the captain was contacted by the tower to say that there was fire / smoke coming from an engine (dunno which one), and the captain decided to abort takeoff. - Hence the blown tyres.
UNQUOTE
QUOTE
The aircraft was going down the runway and the captain was contacted by the tower to say that there was fire / smoke coming from an engine (dunno which one), and the captain decided to abort takeoff. - Hence the blown tyres.
UNQUOTE
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Type certification is invariably completed with new aircraft, new equipment and pilots who know the test program.
So, it's reasonable to assume that the results these people obtain will be the very best that could be hoped for.
Lets advance the clock 20 years with the by now very tired airframe, carrying components whose tolerances are little looser than they ought to be (but still within limits)and a crew that is just expecting a normal take off. Even the rejected brief is a reflection of a legitimate expectation in the crew's mind that the runway will take the aircraft to a full stop. After all, the take off data and figures calculated before departure said so.
I think we can all understand and relate to the mind set here.
Now the reality - We're right up there approaching V1 and there are several loud bangs. Uncertainty as to what has really happened is followed by a decision to reject the take off. There is a resulting slight delay in the application of the retarding devices combined with less than optimal braking system performance.
Next thing - the aircraft is off the runway at the other end.
What went wrong ?
It is FAR too easy to criticise the crew for failing to initiate the rejected manoeuvre early enough. The true cause is a combination of ALL the factors described above.
The largest contributors IMHO, may well be:
1. the performance data is really no longer valid for the condition of the airframe and engines.
2. The gross weight of the aircraft may not be known sufficiently accurately. There may also be c of g error inputs.
This is a very complex issue that should NOT have the crew as the automatic cause of the over run.
Aircraft age and condition play a significant role in what occurs on the runway.
Maybe it's time to start looking at applying degradation factors to the performance tables to try and offset the effects of aircraft aging.
Good luck to the AAI guys.
So, it's reasonable to assume that the results these people obtain will be the very best that could be hoped for.
Lets advance the clock 20 years with the by now very tired airframe, carrying components whose tolerances are little looser than they ought to be (but still within limits)and a crew that is just expecting a normal take off. Even the rejected brief is a reflection of a legitimate expectation in the crew's mind that the runway will take the aircraft to a full stop. After all, the take off data and figures calculated before departure said so.
I think we can all understand and relate to the mind set here.
Now the reality - We're right up there approaching V1 and there are several loud bangs. Uncertainty as to what has really happened is followed by a decision to reject the take off. There is a resulting slight delay in the application of the retarding devices combined with less than optimal braking system performance.
Next thing - the aircraft is off the runway at the other end.
What went wrong ?
It is FAR too easy to criticise the crew for failing to initiate the rejected manoeuvre early enough. The true cause is a combination of ALL the factors described above.
The largest contributors IMHO, may well be:
1. the performance data is really no longer valid for the condition of the airframe and engines.
2. The gross weight of the aircraft may not be known sufficiently accurately. There may also be c of g error inputs.
This is a very complex issue that should NOT have the crew as the automatic cause of the over run.
Aircraft age and condition play a significant role in what occurs on the runway.
Maybe it's time to start looking at applying degradation factors to the performance tables to try and offset the effects of aircraft aging.
Good luck to the AAI guys.
Last edited by Arctaurus; 9th Nov 2004 at 19:42.
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Maybe, just maybe...all this is the result of the poison dwarf's attempts to lower the pay, and hence, less than desirable folks find themselves, in command.
I suspect LH will not be amused.
I suspect LH will not be amused.
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411A: what a batch of twaddle!
I'm fairly certain that the poison leprechaun was nowhere near Sharjah on the day, nor did he jump out from behind the Jeppessens to distract the crew during their unfortunate abort....
Your comments on cutting pay and "and hence, less than desirable folks find themselves, in command." is absolute BOLLUX!
You continue to prove why AAI let you go in the first place. The "DCM medal" ...Don't come Monday.... must absolutely burn on your chest!
Both the Captain and F/O are, to my certain knowledge, much more capable than thou! Your brash, asinine comments have no place in any viable discussion of the issue.
& Doubleu-ancher:
The fact that the pay is below industry standards is not much of your concern, since you're obviously not in the business. Did you happen to "want" to fly for Cathay mainline at some point. I heard the same CR*P from "main-liners" while at AHK.
I'm fairly certain that the poison leprechaun was nowhere near Sharjah on the day, nor did he jump out from behind the Jeppessens to distract the crew during their unfortunate abort....
Your comments on cutting pay and "and hence, less than desirable folks find themselves, in command." is absolute BOLLUX!
You continue to prove why AAI let you go in the first place. The "DCM medal" ...Don't come Monday.... must absolutely burn on your chest!
Both the Captain and F/O are, to my certain knowledge, much more capable than thou! Your brash, asinine comments have no place in any viable discussion of the issue.
& Doubleu-ancher:
The fact that the pay is below industry standards is not much of your concern, since you're obviously not in the business. Did you happen to "want" to fly for Cathay mainline at some point. I heard the same CR*P from "main-liners" while at AHK.
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Alex Whittingham offers a more than adequate description of a reject before, around, or after V1.
For those who have never flown heavy jets, where field length and de-rated takeoffs are FAR more critical than lighter commercials, it is well accepted that an RTO is considered less and less preferable, the closer one gets to V1.
However, superimposed on this is the uncertainty of what failure has occurred, on hearing "bangs" or "thumps" and "vibration" in the 747 cockpit, which is far removed from the engines and the gear, so it is not always obvious whether you are having maybe a surge/compressor stall/or a blow out.
Sympathies for the crew, no professional wishes ANY incident on ANY crew!
Alex....cheers for the Perf A Refresher course 10 years ago at Gatwick! Been flying 747's ever since!
For those who have never flown heavy jets, where field length and de-rated takeoffs are FAR more critical than lighter commercials, it is well accepted that an RTO is considered less and less preferable, the closer one gets to V1.
However, superimposed on this is the uncertainty of what failure has occurred, on hearing "bangs" or "thumps" and "vibration" in the 747 cockpit, which is far removed from the engines and the gear, so it is not always obvious whether you are having maybe a surge/compressor stall/or a blow out.
Sympathies for the crew, no professional wishes ANY incident on ANY crew!
Alex....cheers for the Perf A Refresher course 10 years ago at Gatwick! Been flying 747's ever since!
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Well we will always have the bashers that will whine and whinge about pay and conditions. But if their so called super duper paying airlines started retrenching and they found themselves out on the street with bills to pay and kids to feed, it would be so amazing how bloody fast their super duper high standards and morals would fall apart like farts in the wind.
Guys and girls take jobs after reading the contracts, renegotiating points and signing on the dotted line with eyes wide open. No point whinging after the fact. If terms and conditions not suitable don't sign.
Maintenance standards. Well from speedbird to bangbird most if not all flight crews have no idea what maintenence standards are and what screw ups are kept in house. Just because the LAE smiles at you and says he will take care of it doesn't mean a thing. The crew have left the scene and in a big operation would probably not fly the same aircraft for sometime. How many pilots scrutinise the MR for defered items in the MR2 that they have entered in the MR1 months ago (Who really remembers and tracks this)
Rejected take off, I agree with all you guys have written and would like to add.
V1, Must be greater than VMCG. Not less than VMBE. With 1 second to recognise. 1 second confirm and 1 second to react.
Rejecting a takeoff after V1 is acceptable if the Captain asseses that the aerodynamic capability of the aircraft is in doubt and would be detrimental to safe flight.
Wooblah.
Guys and girls take jobs after reading the contracts, renegotiating points and signing on the dotted line with eyes wide open. No point whinging after the fact. If terms and conditions not suitable don't sign.
Maintenance standards. Well from speedbird to bangbird most if not all flight crews have no idea what maintenence standards are and what screw ups are kept in house. Just because the LAE smiles at you and says he will take care of it doesn't mean a thing. The crew have left the scene and in a big operation would probably not fly the same aircraft for sometime. How many pilots scrutinise the MR for defered items in the MR2 that they have entered in the MR1 months ago (Who really remembers and tracks this)
Rejected take off, I agree with all you guys have written and would like to add.
V1, Must be greater than VMCG. Not less than VMBE. With 1 second to recognise. 1 second confirm and 1 second to react.
Rejecting a takeoff after V1 is acceptable if the Captain asseses that the aerodynamic capability of the aircraft is in doubt and would be detrimental to safe flight.
Wooblah.
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Guys and girls take jobs after reading the contracts, renegotiating points and signing on the dotted line with eyes wide open. No point whinging after the fact. If terms and conditions not suitable don't sign.
As for the whinging part it this is the only job that pilot are really good at
Last edited by Engineer; 12th Nov 2004 at 09:55.
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With only the responses I´ve seen since my last response I must admit that I´ve lost all faith in the credibility of the one´s responding to my initial post.
it´s actually just now how i realise how much of a wannabe website this has become.
it´s actually just now how i realise how much of a wannabe website this has become.
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Alex you made me laugh, AN 124 obviously does not know you back ground as we do.
And for the rest of you guys who are making judgements about what the crew should have done and what they did not do, you are going to have egg on your face when the final report comes out, trust me.
I standby my first posting on this subject, unless you where in the flight deck you can not assume the correct actions to be taken.
Even if the assumptions in the post are correct and they stopped for burst tires, this does not mean they made an error of judgement.
In the sim it's easy a burst tire goes bang, and the aircraft swings, in real life this may not be what happens.
And for the rest of you guys who are making judgements about what the crew should have done and what they did not do, you are going to have egg on your face when the final report comes out, trust me.
I standby my first posting on this subject, unless you where in the flight deck you can not assume the correct actions to be taken.
Even if the assumptions in the post are correct and they stopped for burst tires, this does not mean they made an error of judgement.
In the sim it's easy a burst tire goes bang, and the aircraft swings, in real life this may not be what happens.