MK Airlines B747 crash at Halifax
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csomesense,
I hear what you're saying but having myself worked in cargo for 5+ years not only have I witnessed the cutting of corners but I mixed & drank with MK crews in the Ter Streep bar, Ostend.
I would say that MK has been like an accident waiting to happen but in their case would need to omit the waiting part.
Any airline may be only as good or bad as it's regulating authority permit it to be.
In the instance of an African registration, an airline pays a poorer nation to be registered there and that country does not want to deter such business thus they do not enforce regulations nor inspect the airline to ensure regulations are being adhered to.
Does it not concern you that such unregulated airlines and aircraft have European & N. American traffic rights and it could be your house they're flying over at some time in the future?
Regulated airlines spend a bucket load of money ensuring regulations are adhered to and often cannot compete with non-regulated airlines who may put profit before safety.
If African countries want to allow potentially dangerous aircraft into the air then perhaps those aircraft should be restricted to flying over Africa!
I hear what you're saying but having myself worked in cargo for 5+ years not only have I witnessed the cutting of corners but I mixed & drank with MK crews in the Ter Streep bar, Ostend.
I would say that MK has been like an accident waiting to happen but in their case would need to omit the waiting part.
Any airline may be only as good or bad as it's regulating authority permit it to be.
In the instance of an African registration, an airline pays a poorer nation to be registered there and that country does not want to deter such business thus they do not enforce regulations nor inspect the airline to ensure regulations are being adhered to.
Does it not concern you that such unregulated airlines and aircraft have European & N. American traffic rights and it could be your house they're flying over at some time in the future?
Regulated airlines spend a bucket load of money ensuring regulations are adhered to and often cannot compete with non-regulated airlines who may put profit before safety.
If African countries want to allow potentially dangerous aircraft into the air then perhaps those aircraft should be restricted to flying over Africa!
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Css,
Sorry, bad English. Rumor has it that they took the published VOR approach “enhanced” it by adding GPS that, I suppose, emboldened them to ignore the published minima. The end result was that they could not see the runway when they hit the trees!
(above refers to previous accident in Nigeria)
An-124
Thanks for that. It is all a question of timing. The FAA issued Ghana Airways with a directive not to fly their aircraft to the US on or about the 23 July. MK were still flying to the US after that (this flight transited Bradley International on the 14 October) One can only conclude that MK no longer fly over US airspace as a direct result of this tragic accident.
Sorry, bad English. Rumor has it that they took the published VOR approach “enhanced” it by adding GPS that, I suppose, emboldened them to ignore the published minima. The end result was that they could not see the runway when they hit the trees!
(above refers to previous accident in Nigeria)
An-124
Thanks for that. It is all a question of timing. The FAA issued Ghana Airways with a directive not to fly their aircraft to the US on or about the 23 July. MK were still flying to the US after that (this flight transited Bradley International on the 14 October) One can only conclude that MK no longer fly over US airspace as a direct result of this tragic accident.
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dear fellows,
i think this might be a case where murphy struck again at it best: good engine take off parameters caculations but wrong epr settings or wrong calculations with corresponding good epr settings to the same catastrophic result : not enough t/o thrust?
on t/o epr settings are x checked with n1,( emphasized after the air florida accident in the potomac river washington dc, iced up epr probes)but at night in a dimly lit cockpit the difference between a correct n1 or not might not so easy to be seen( murphy again) bring in another couple of the same things in (fatigue eg) & there goes the swiss cheese with all the wholes perfectly (7 à 8 according to the stat's)aligned & an accident waiting to happen at the end of an of course limiting rwy, with some bumps & other obstacle stuff in the overrun area, very sad indeed! reminds me of a similar overrun long ago, of a swiss dc-8 in former athens airport, but on a long landing this time on a slippery rwy, breaking up in a ditch in the overrun area.
pilots were later put on trial & even jailed by the greek authorities. nobody ever asked why it was necessary to dig a ditch in an overrun area!
it's all about: "situational awareness"?
there are some indications the mkcrew realized this late in the tor & put up the thrust, but too late unfortunately. ...
i think this might be a case where murphy struck again at it best: good engine take off parameters caculations but wrong epr settings or wrong calculations with corresponding good epr settings to the same catastrophic result : not enough t/o thrust?
on t/o epr settings are x checked with n1,( emphasized after the air florida accident in the potomac river washington dc, iced up epr probes)but at night in a dimly lit cockpit the difference between a correct n1 or not might not so easy to be seen( murphy again) bring in another couple of the same things in (fatigue eg) & there goes the swiss cheese with all the wholes perfectly (7 à 8 according to the stat's)aligned & an accident waiting to happen at the end of an of course limiting rwy, with some bumps & other obstacle stuff in the overrun area, very sad indeed! reminds me of a similar overrun long ago, of a swiss dc-8 in former athens airport, but on a long landing this time on a slippery rwy, breaking up in a ditch in the overrun area.
pilots were later put on trial & even jailed by the greek authorities. nobody ever asked why it was necessary to dig a ditch in an overrun area!
it's all about: "situational awareness"?
there are some indications the mkcrew realized this late in the tor & put up the thrust, but too late unfortunately. ...
Last edited by blackmail; 16th Nov 2004 at 10:07.
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The conjecture is that a glitch in the Boeing performance software may be a factor. I've never used it, but it's been said that it's possible to enter new numbers, but if you don't execute the change, the calculations will be based on the previous numbers. So, if they were alot lighter on departure out of BDL, and they didn't execute their new weight numbers out of YHZ, the computer may have given speeds and EPR for a much lower weight.
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That is what I was told.
I don't want the information I have posted to be misconstrued. There is great value in the electronic flight bag products that are available on the market today. I fully expect to see a big shift to their use in the coming years. I'd love to see the 50 kgs of books taken out of our cockpits. They're a huge safety hazard in a sudden RTO, never mind how much fuel it costs to carry them around.
Like everything else, a shift to automation must come with a thorough study of the man-machine interface to ensure that adequate checks and balances are in place to validate the information. As the old saying goes, "Garbage in, garbage out." In the middle of the night on a quick turn around, it's easy to make a mistake.
I don't want the information I have posted to be misconstrued. There is great value in the electronic flight bag products that are available on the market today. I fully expect to see a big shift to their use in the coming years. I'd love to see the 50 kgs of books taken out of our cockpits. They're a huge safety hazard in a sudden RTO, never mind how much fuel it costs to carry them around.
Like everything else, a shift to automation must come with a thorough study of the man-machine interface to ensure that adequate checks and balances are in place to validate the information. As the old saying goes, "Garbage in, garbage out." In the middle of the night on a quick turn around, it's easy to make a mistake.
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Sorry but I'm confused. They were at max TOW. Would (should) they not automatically (without recourse to SOPs, manuals, laptops, etc.) have set max power setting for the TO? Or am I being naive?
Rockhound
Rockhound
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On large transport jets, takeoffs with reduced thrust are routine practice, even at maximum weight. There are specific tables and routine procedures for determining the takeoff thrust and speeds. It all depends on the available runway length and the climb requirements. According to the reports, they did not set the proper thrust for the takeoff. There must be a reason for that. The most likely cause is an error in the takeoff performance calculation, which resulted in a lower than required power setting.
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Reduced Thrust
Good post Safety Guy
Your explanation was right on the money.
Using reduced thrust reduces wear and tear on engines by keeping temperatures lower. Used daily all around the world, no biggie. Once again a good explanation to a someone who is perhaps not as knowledgeable on the principles of reduced thrust or flies type of aircraft where it is not used.
AD
Your explanation was right on the money.
Using reduced thrust reduces wear and tear on engines by keeping temperatures lower. Used daily all around the world, no biggie. Once again a good explanation to a someone who is perhaps not as knowledgeable on the principles of reduced thrust or flies type of aircraft where it is not used.
AD
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They also should have been at flaps 20 for this particular takeoff. You could probably make it at flaps 10 if the thrust had been set correctly, but just by the skin of your arse so using flaps 20 would increase safety margins exponentially. 
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Safety Guy and others,
Thanks for that. But for a TO at max weight, or close to it, would the appropriate reduced PWR setting not be pretty close to the maximum, so that anything significantly less would become obvious immediately? I am not a pilot, just an interested observer and sincerely appreciate learning from the pros.
Rockhound
Thanks for that. But for a TO at max weight, or close to it, would the appropriate reduced PWR setting not be pretty close to the maximum, so that anything significantly less would become obvious immediately? I am not a pilot, just an interested observer and sincerely appreciate learning from the pros.
Rockhound
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Rockhound:
A very good question, and the answer depends on several variables. I'm not an expert on B747 performance, but I understand that it has a pretty significant power reserve, therefore max thrust takeoffs are a pretty rare event. I fly the A330, and I've done max weight takeoffs at 30°C with a thrust reduction up to 25% of the maximum rated thrust.
Your comment regarding the lower power setting being noticeable to a crew is valid, but there are many factors which can reduce the crew's awareness of their acceleration rate (this is my speculation only). The older 747 doesn't have acceleration rate indicators like newer aircraft have (i.e. the Airbus speed trend arrow). One factor on runway 24 in YHZ is that the far end of the runway is lower than the mid point, and it may be that the crew didn't realize their proximity to the far end until it was too late.
It is sad that the CVR is not useable, as I am sure that it would have revealed much more than what will otherwise be found in this case. As always, I suspect that this tragedy was the result of a series of inductive events.
SG
A very good question, and the answer depends on several variables. I'm not an expert on B747 performance, but I understand that it has a pretty significant power reserve, therefore max thrust takeoffs are a pretty rare event. I fly the A330, and I've done max weight takeoffs at 30°C with a thrust reduction up to 25% of the maximum rated thrust.
Your comment regarding the lower power setting being noticeable to a crew is valid, but there are many factors which can reduce the crew's awareness of their acceleration rate (this is my speculation only). The older 747 doesn't have acceleration rate indicators like newer aircraft have (i.e. the Airbus speed trend arrow). One factor on runway 24 in YHZ is that the far end of the runway is lower than the mid point, and it may be that the crew didn't realize their proximity to the far end until it was too late.
It is sad that the CVR is not useable, as I am sure that it would have revealed much more than what will otherwise be found in this case. As always, I suspect that this tragedy was the result of a series of inductive events.
SG
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A little inside info.......
EPR was set to 1.3 at beginning of takeoff role. This is the lowest amount of derate for any takeoff under any conditions. (Why this did not appear odd to the person setting the thrust is beyond me)
Sometime around V1, someone on the flight deck set the thrust to what it should have been set originally.
At no time was the throttle firewalled. Somebody on the flight deck knew the proper throttle setting. It was set incorrectly. To move the throttle levers deliberately from 1.3 to the EXACT EPR it should have been leads me to believe it was just a simple mistake. If they had firewalled the throttles, that would have meant they realized they weren't using enough thrust but not know what it really should be.
In the end, instead of going to max forward thrust they should have went to full reverse with brakes and slid into that berm at around 50 kts. Plane would have been lost but the crew would have walked away.
EPR was set to 1.3 at beginning of takeoff role. This is the lowest amount of derate for any takeoff under any conditions. (Why this did not appear odd to the person setting the thrust is beyond me)
Sometime around V1, someone on the flight deck set the thrust to what it should have been set originally.
At no time was the throttle firewalled. Somebody on the flight deck knew the proper throttle setting. It was set incorrectly. To move the throttle levers deliberately from 1.3 to the EXACT EPR it should have been leads me to believe it was just a simple mistake. If they had firewalled the throttles, that would have meant they realized they weren't using enough thrust but not know what it really should be.
In the end, instead of going to max forward thrust they should have went to full reverse with brakes and slid into that berm at around 50 kts. Plane would have been lost but the crew would have walked away.
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"Sometime around V1......instead of going to max forward thrust they should have went to full reverse with brakes and slid into that berm at around 50 kts" ???
Was it before or after V1. I suspect it was after, as I think we would all agree that once that magical figure has been reached, every fibre in your being screams that you must go, no matter what? It certainly doesn't enter my head to entertain stopping after V1. Maybe I'm not as Super-Human as you though?
Was it before or after V1. I suspect it was after, as I think we would all agree that once that magical figure has been reached, every fibre in your being screams that you must go, no matter what? It certainly doesn't enter my head to entertain stopping after V1. Maybe I'm not as Super-Human as you though?
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747focal, I assume you have access to FDR data. It seems to me that this takeoff was a pretty tight balanced field situation. I can't imagine that they somehow didn't grasp that approaching V1 at reduced power, shot their balanced field numbers all to heck. Maybe fatigue would explain this.
Anyway you look at it, they were in a bad fix if they didn't discover the low power settings until V1 (much farther down the runway than V1 should have been).
Anyway you look at it, they were in a bad fix if they didn't discover the low power settings until V1 (much farther down the runway than V1 should have been).
Last edited by Flight Safety; 16th Nov 2004 at 20:47.
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Yes I have access to what the avg aviation person would not.
Flight Safety,
Your right, given the same circumstances and past V1 my training would have told me to hold fast. Hindsight is 20/ 20. On fire or not going to make it, I choose hitting the brakes. Hopefully the souls behind me will live to fly again another day.
They teach us that V1 is the no go, when in reality there is a whole bunch of buffer/slop in there. So what if you buy the field, farm or highway beyond the end of the runway. Chances of surviving increase dramatically if you never leave the ground.
The reality of our calculations is that when they went to 1.6 EPR, if they had went to full reverse thrust and brakes they would have stopped some 100 yds short of the bearm that ended up breaking off the tail.
Flight Safety,
Your right, given the same circumstances and past V1 my training would have told me to hold fast. Hindsight is 20/ 20. On fire or not going to make it, I choose hitting the brakes. Hopefully the souls behind me will live to fly again another day.
They teach us that V1 is the no go, when in reality there is a whole bunch of buffer/slop in there. So what if you buy the field, farm or highway beyond the end of the runway. Chances of surviving increase dramatically if you never leave the ground.
The reality of our calculations is that when they went to 1.6 EPR, if they had went to full reverse thrust and brakes they would have stopped some 100 yds short of the bearm that ended up breaking off the tail.
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From this accident, I'm learning that there's something of a dark side to what "csomesense" referred to as the "magical figure" V1.
When the calculations are done for the runway, weight, field conditions, etc before a takeoff, the figure V1 is assumed to represent the "go no-go" decision speed. The V1 speed is based on the assumption that the aircraft will accelerate at a known rate for the calculated power setting, and thus V1 will be achieved at a predetermined spot some distance down the runway. The whole idea of V1 speed being the "go no-go" decision threshold, is based on the simple assumption that right when V1 is reached, so many feet of runway will be behind you, and so many feet of runway will be ahead of you to successfully abort a takeoff if needed. However the calculated V1 speed is meaningless as the "go no-go" decision point, if you reach V1 at some other point farther down the runway.
Clearly in this accident, if the power settings were too low at the start of the takeoff roll, any length of time accelerating with power settings below what was calculated, will cause you to arrive at V1 a lot farther down the runway than you intended. At this point the calculated V1 is meaningless as a "go no-go" decision speed, as you have no idea how much runway is left (though less for sure) and whether you can takeoff or stop in time.
What your options are at such a point (discovering that your power settings were too low near V1) I'm not really sure. I guess you'd have no other choice but to decide which way is the best way to break the airplane, either accelerating or deccelerating. Personally I'd prefer the lower energy impact myself.
747focal, I think we pretty much see this the same way.
When the calculations are done for the runway, weight, field conditions, etc before a takeoff, the figure V1 is assumed to represent the "go no-go" decision speed. The V1 speed is based on the assumption that the aircraft will accelerate at a known rate for the calculated power setting, and thus V1 will be achieved at a predetermined spot some distance down the runway. The whole idea of V1 speed being the "go no-go" decision threshold, is based on the simple assumption that right when V1 is reached, so many feet of runway will be behind you, and so many feet of runway will be ahead of you to successfully abort a takeoff if needed. However the calculated V1 speed is meaningless as the "go no-go" decision point, if you reach V1 at some other point farther down the runway.
Clearly in this accident, if the power settings were too low at the start of the takeoff roll, any length of time accelerating with power settings below what was calculated, will cause you to arrive at V1 a lot farther down the runway than you intended. At this point the calculated V1 is meaningless as a "go no-go" decision speed, as you have no idea how much runway is left (though less for sure) and whether you can takeoff or stop in time.
What your options are at such a point (discovering that your power settings were too low near V1) I'm not really sure. I guess you'd have no other choice but to decide which way is the best way to break the airplane, either accelerating or deccelerating. Personally I'd prefer the lower energy impact myself.
747focal, I think we pretty much see this the same way.
Last edited by Flight Safety; 17th Nov 2004 at 14:23.
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Gentlemen:
Your comments and analysis are interesting and definitely food for thought, but we must remember that this crew had little if any time to think about their options once they realised they were in trouble. Let's face it, when was the last time that simulator training included such a scenario as this one, other than in a wind shear inducing condition?
I also think that there's a slippery slope to be taken if we muddy the waters of what to do when V1 is reached. Short of an being in an un-flyable airplane, V1 should mean GO! From what is known so far, it appears that this accident is the result of very rare set of circumstances. Let's not throw the baby out with the bath water!
The focus should be on preventing a repeat of the inducing circumstances, not on changing a well documented and researched operating philosophy.
SG
Your comments and analysis are interesting and definitely food for thought, but we must remember that this crew had little if any time to think about their options once they realised they were in trouble. Let's face it, when was the last time that simulator training included such a scenario as this one, other than in a wind shear inducing condition?
I also think that there's a slippery slope to be taken if we muddy the waters of what to do when V1 is reached. Short of an being in an un-flyable airplane, V1 should mean GO! From what is known so far, it appears that this accident is the result of very rare set of circumstances. Let's not throw the baby out with the bath water!
The focus should be on preventing a repeat of the inducing circumstances, not on changing a well documented and researched operating philosophy.
SG
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747Focal,
I don't think much of your theory that, when one of the crew, at around V1, increased the EPR setting from 1.3 to (the correct) 1.6, he was simply correcting an earlier mistake. V1 being far into the TO roll, when he recognized the low power setting but at the same time intending to continue the TO, surely to God he would have instinctively firewalled the throttles to squeeze out the last ounce of thrust, get airborne and to hell with the increased wear and tear on the engines, exceeding calculated EPR, etc., etc.
Rockhound
I don't think much of your theory that, when one of the crew, at around V1, increased the EPR setting from 1.3 to (the correct) 1.6, he was simply correcting an earlier mistake. V1 being far into the TO roll, when he recognized the low power setting but at the same time intending to continue the TO, surely to God he would have instinctively firewalled the throttles to squeeze out the last ounce of thrust, get airborne and to hell with the increased wear and tear on the engines, exceeding calculated EPR, etc., etc.
Rockhound