Helicopter Height-Velocity (H-V) limitations
Momentary exposure in a modern twin should be allowed... its sensible and the risk is negligible
Two years or so later in the same aircraft an engine failure at the commencement of a TO from a runway while Cat B. A failure 30 seconds later would have written off the aircraft. To me it doesn't measure up to the 10*-9 expected of our systems. Would any of you gladly hop on your 737, 320 etc if you knew a failure at V1 was going to end in a possible close encounter with objects in the over run ie having no guaranteed performance accountability?
Helicopters have enough failure scenarios to give you sleepless nights, tail rotors, gearboxes for example, why short change pax and crews by having exposure in an area that is so easily avoided. In saying so I recognise the impact of such an aircraft to operator costs etc.
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Megan
You have to look hard to find specific examples in the offshore world where an engine power loss during a critical phase of flight has been the primary cause of an accident in the recent past, even with older twins. It doesn't mean they haven't happened, nor does it diminish your experiences, its simply a reality.
I'm pleased you brought up the 737/A320 example as it helps make my point about reliability. For all the single engine performance those aircraft have, I can't think of an instance where any of the pilots I know flying those types, or anyone who has been a passenger on them, including me, has ever been in a situation that has required its use in an OEI situation. That's not to say they don't fail, they just fail rarely. Sadly modern airliners still spear into the ground for a whole host of other non engine related reasons. An aircraft's OEI capability gives me no comfort when the people in front run me into the berm at the end of the runway because they don't know how their airplane works (in the case of the Asiana 777 at SFO).
Don't get me wrong, I like flying machines that have plenty of OEI power, however I want regulators to be focusing their attentions on the big picture. As Geoffers rightly points out, we are operating in a regulatory system that no longer reflects our operational realities, perhaps hasn't for a long time. New aircraft have an exciting range of technologies that we can't remotely use to there full capabilities, primarily for regulatory reasons. I want regulators focused on rules that let me use those abilities to there maximum in ways that will really make a difference to safety. Getting bogged down about momentary exposure into a flight envelope that is so imprecise and inexact is a distraction.
You have to look hard to find specific examples in the offshore world where an engine power loss during a critical phase of flight has been the primary cause of an accident in the recent past, even with older twins. It doesn't mean they haven't happened, nor does it diminish your experiences, its simply a reality.
I'm pleased you brought up the 737/A320 example as it helps make my point about reliability. For all the single engine performance those aircraft have, I can't think of an instance where any of the pilots I know flying those types, or anyone who has been a passenger on them, including me, has ever been in a situation that has required its use in an OEI situation. That's not to say they don't fail, they just fail rarely. Sadly modern airliners still spear into the ground for a whole host of other non engine related reasons. An aircraft's OEI capability gives me no comfort when the people in front run me into the berm at the end of the runway because they don't know how their airplane works (in the case of the Asiana 777 at SFO).
Don't get me wrong, I like flying machines that have plenty of OEI power, however I want regulators to be focusing their attentions on the big picture. As Geoffers rightly points out, we are operating in a regulatory system that no longer reflects our operational realities, perhaps hasn't for a long time. New aircraft have an exciting range of technologies that we can't remotely use to there full capabilities, primarily for regulatory reasons. I want regulators focused on rules that let me use those abilities to there maximum in ways that will really make a difference to safety. Getting bogged down about momentary exposure into a flight envelope that is so imprecise and inexact is a distraction.
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Quite right Garry M
and can I just shoot down the 737 arguement right now:
aeroplanes are different
the 737 needs 2 engines because it does not land well enroute, in the wild, it needs a very special arrival surface
the 737 spends it's entire flight time exposed to catastrophic consequences if it lost all power, it's really not the same as the very brief exposure a helicopter might have during t/o
the maths is different for the 737 and the helicopter
there are several reasons why a helicopter may have to ditch, way way down on the list is engine failure during takeoff, so helicopters need to be able to ditch 'safely'
if you factor the chance of engine failure by the proportion of time spent transitioning through the HV curve on t/o you get an incredibly small number even when you do multiply by 2 (in a twin having twice the number of engines with which to have this failure), almost certainly not outweighing the more significant negative downsides of carrying such an excess in engine power
Megan I don't wish to diminish your beliefs founded in your extra ordinary experience but perhaps you could reflect on the statistical phenomenon of having 2 engine failures in 2 years on the same aircraft at this critical phase of flight. It is so statisticaly amazing as to suggest some other causual common factor to these events that almost could not happen otherwise
this is an old fashioned solution to a 'problem' that isn't 'the problem'
and can I just shoot down the 737 arguement right now:
aeroplanes are different
the 737 needs 2 engines because it does not land well enroute, in the wild, it needs a very special arrival surface
the 737 spends it's entire flight time exposed to catastrophic consequences if it lost all power, it's really not the same as the very brief exposure a helicopter might have during t/o
the maths is different for the 737 and the helicopter
there are several reasons why a helicopter may have to ditch, way way down on the list is engine failure during takeoff, so helicopters need to be able to ditch 'safely'
if you factor the chance of engine failure by the proportion of time spent transitioning through the HV curve on t/o you get an incredibly small number even when you do multiply by 2 (in a twin having twice the number of engines with which to have this failure), almost certainly not outweighing the more significant negative downsides of carrying such an excess in engine power
Megan I don't wish to diminish your beliefs founded in your extra ordinary experience but perhaps you could reflect on the statistical phenomenon of having 2 engine failures in 2 years on the same aircraft at this critical phase of flight. It is so statisticaly amazing as to suggest some other causual common factor to these events that almost could not happen otherwise
this is an old fashioned solution to a 'problem' that isn't 'the problem'
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Quite right Garry M
and can I just shoot down the 737 arguement right now:
aeroplanes are different
the 737 needs 2 engines because it does not land well enroute, in the wild, it needs a very special arrival surface
the 737 spends it's entire flight time exposed to catastrophic consequences if it lost all power, it's really not the same as the very brief exposure a helicopter might have during t/o
the maths is different for the 737 and the helicopter
there are several reasons why a helicopter may have to ditch, way way down on the list is engine failure during takeoff, so helicopters need to be able to ditch 'safely'
if you factor the chance of engine failure by the proportion of time spent transitioning through the HV curve on t/o you get an incredibly small number even when you do multiply by 2 (in a twin having twice the number of engines with which to have this failure), almost certainly not outweighing the more significant negative downsides of carrying such an excess in engine power
Megan I don't wish to diminish your beliefs founded in your extra ordinary experience but perhaps you could reflect on the statistical phenomenon of having 2 engine failures in 2 years on the same aircraft at this critical phase of flight. It is so statisticaly amazing as to suggest some other causual common factor to these events that almost could not happen otherwise
this is an old fashioned solution to a 'problem' that isn't 'the problem'
and can I just shoot down the 737 arguement right now:
aeroplanes are different
the 737 needs 2 engines because it does not land well enroute, in the wild, it needs a very special arrival surface
the 737 spends it's entire flight time exposed to catastrophic consequences if it lost all power, it's really not the same as the very brief exposure a helicopter might have during t/o
the maths is different for the 737 and the helicopter
there are several reasons why a helicopter may have to ditch, way way down on the list is engine failure during takeoff, so helicopters need to be able to ditch 'safely'
if you factor the chance of engine failure by the proportion of time spent transitioning through the HV curve on t/o you get an incredibly small number even when you do multiply by 2 (in a twin having twice the number of engines with which to have this failure), almost certainly not outweighing the more significant negative downsides of carrying such an excess in engine power
Megan I don't wish to diminish your beliefs founded in your extra ordinary experience but perhaps you could reflect on the statistical phenomenon of having 2 engine failures in 2 years on the same aircraft at this critical phase of flight. It is so statisticaly amazing as to suggest some other causual common factor to these events that almost could not happen otherwise
this is an old fashioned solution to a 'problem' that isn't 'the problem'
Since the case of a 737 needing two engines because of en-route safety was cited, will AnFI please remind us how a single engine helicopter will avoid ditching after an engine failure whilst en-route to an offshore installation? Safely?
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er heli
the 737 point was raised by xxx to argue against the exposure of the brief transit of the hv curve, it is not a valid arguement because the main reason why the 737 has 2 engines is for the enroute phase, where the consequence for the 737 of forced landing is so severe compared to the helicopter.
helicopters do not need to avoid ditching as 737s do, they just need to be able to ditch safely, a feat often demonstrated by twins and sometimes singles too.
ditching isn't bad, dying is
and could you try and avoid being so rude "More simplistic nonsense..."
personally (and for many others) carrying 2 engines is simplistic 1950's nonsense, but at least I have the civility to attempt to proffer logical points. PC12s do well on one engine and helicopters are even more suited to single engine than are aeroplanes (autorotation).
this discussion is more about the brief transit of the hv curve, and it is fairly clear that it is not a significant safety concern, as the salesman from AW was suggesting.
the 737 point was raised by xxx to argue against the exposure of the brief transit of the hv curve, it is not a valid arguement because the main reason why the 737 has 2 engines is for the enroute phase, where the consequence for the 737 of forced landing is so severe compared to the helicopter.
helicopters do not need to avoid ditching as 737s do, they just need to be able to ditch safely, a feat often demonstrated by twins and sometimes singles too.
ditching isn't bad, dying is
and could you try and avoid being so rude "More simplistic nonsense..."
personally (and for many others) carrying 2 engines is simplistic 1950's nonsense, but at least I have the civility to attempt to proffer logical points. PC12s do well on one engine and helicopters are even more suited to single engine than are aeroplanes (autorotation).
this discussion is more about the brief transit of the hv curve, and it is fairly clear that it is not a significant safety concern, as the salesman from AW was suggesting.
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er heli
the 737 point was raised by xxx to argue against the exposure of the brief transit of the hv curve, it is not a valid arguement because the main reason why the 737 has 2 engines is for the enroute phase, where the consequence for the 737 of forced landing is so severe compared to the helicopter.
helicopters do not need to avoid ditching as 737s do, they just need to be able to ditch safely, a feat often demonstrated by twins and sometimes singles too.
ditching isn't bad, dying is
and could you try and avoid being so rude "More simplistic nonsense..."
personally (and for many others) carrying 2 engines is simplistic 1950's nonsense, but at least I have the civility to attempt to proffer logical points. PC12s do well on one engine and helicopters are even more suited to single engine than are aeroplanes (autorotation).
this discussion is more about the brief transit of the hv curve, and it is fairly clear that it is not a significant safety concern, as the salesman from AW was suggesting.
the 737 point was raised by xxx to argue against the exposure of the brief transit of the hv curve, it is not a valid arguement because the main reason why the 737 has 2 engines is for the enroute phase, where the consequence for the 737 of forced landing is so severe compared to the helicopter.
helicopters do not need to avoid ditching as 737s do, they just need to be able to ditch safely, a feat often demonstrated by twins and sometimes singles too.
ditching isn't bad, dying is
and could you try and avoid being so rude "More simplistic nonsense..."
personally (and for many others) carrying 2 engines is simplistic 1950's nonsense, but at least I have the civility to attempt to proffer logical points. PC12s do well on one engine and helicopters are even more suited to single engine than are aeroplanes (autorotation).
this discussion is more about the brief transit of the hv curve, and it is fairly clear that it is not a significant safety concern, as the salesman from AW was suggesting.
The concept that "helicopters do not need to avoid ditching as 737s do, they just need to be able to ditch safely" is more of the same drum beating that AnFI has been bringing to the forum for way too long with his crusade to outlaw any more than one engine per helicopter. It is tedious, it is based on poor reasoning and is so predictable that it is bound to detract from any reasonable discussion where twin engine ops are raised on Rotorheads.
Avoiding ditching by having adequate reserve power in any aircraft is a duty owed to the paying passengers and to the crew. Quite how the bears would take to being told they are quite safe in AnFIs flawed logic when flying over a sea state 7 on a dark winter's day in the North Sea because it's OK as long as they can ditch safely, beggars the imagination.
heli - in AnFI's mind, his is a reasoned and coherent argument based purely on statistics - he has no experience of real-world ops in a twin where the number of times the crew is exposed to a dramatic outcome in the event of a SEF is far more than he can conceive.
The dismissal of ditching as an acceptable outcome is typical of someone who has spent little time over the water - especially in large sea states - and has never been dunker trained.
Lies, damn lies and statistics is a well worn phrase - I for one don't trust statistics as anything other than an analysis of what has happened rather than a predictor of what might happen.
The dismissal of ditching as an acceptable outcome is typical of someone who has spent little time over the water - especially in large sea states - and has never been dunker trained.
Lies, damn lies and statistics is a well worn phrase - I for one don't trust statistics as anything other than an analysis of what has happened rather than a predictor of what might happen.
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Dear AnFI,
you require not to be "rude" (see your response to Heli) but you insist to define me
"the salesman from AW".
I am not a salesman and the proof is that the point I raised is finding a considerable number of supporters. Are all salesmen?
Have a nice weekend.
you require not to be "rude" (see your response to Heli) but you insist to define me
"the salesman from AW".
I am not a salesman and the proof is that the point I raised is finding a considerable number of supporters. Are all salesmen?
Have a nice weekend.
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Heli:
"is more of the same drum beating that AnFI has been bringing to the forum for way too long with his crusade to outlaw any more than one engine per helicopter. It is tedious, it is based on poor reasoning and is so predictable that it is bound to detract from any reasonable discussion where twin engine ops are raised on Rotorheads."
There's no material in there. The mods seem to accept this rude approach provided it is on the twin engine side of the 'discussion'.
As for your point about fare paying passengers and avoiding ditching etc, that is a different point, 2 engines in the cruise over a hostile surface when they are so poor at ditching has a natural attraction, especially in the NoTech mind of the 'bears'. (and I don't know, if you gave them the choice of the heli that can land safely on the water and the one that can't (but theoretically won't need to), maybe they would choose the safer one?)
The excess power to avoid exposure during t/o is a different discussion. There is simply no factual safety case for it AFAIK. It's hypothetical armchair layperson stuff, the kind of hypothetical that Crab doesn't like.
These NS machines seem to have a fairly poor record considering that they are flying the simplest type of flight (mostly autopilot cruise), loaded with safety aids, 2 commercial pilots, huge training / checking.
Crab: "his (AnFi) is a reasoned and coherent argument based purely on statistics" thanks
Crab: "The dismissal of ditching as an acceptable outcome is typical of someone who has spent little time over the water - especially in large sea states - and has never been dunker trained." I note that you are rightly not suggesting that is the case with me, merely that others also share this view. Obviously ditching is an acceptable outcome IMO when one's gearbox is on the way out for example, you don't think so?
(maybe I don't have oversea flying experience, ditching experience nor dunker training. Or maybe I do, but the logic is the point, not a discussion of your relatively limited experience)
If the risk of ditching were reduced to an acceptable level then twins would not need to waste payload on floats. In fact they ditch often enough to need to be good at it. (maybe better than they are)
Crab: "I for one don't trust statistics as anything other than an analysis of what has happened rather than a predictor of what might happen. " .... and Ronnie Regan used to consult astrologers but it's not a really sound way to design aircraft is it.
gmrwiz, I am sorry I really genuinely don't mean to be rude and I'd love to engage respectfully with you on the issues. As for your suggestion that being an AW salesman is an insult, I think that AW salesmen might be offended by that, AW salesmen have done a superb job and have been very succesful. I was just concerned that you were trying to suggest that prohibiting exposure during t/o had an obvious safety benefit, when it is the opinion of some of the most technically aware on this forum that it does not. (although it is not obvious, there are increased risks consequent from eliminating that one)
The reasoning requires more space than this forum allows but an example of one point is:
If a helicopter can be operated without exposure with 2 pax, but would be exposed with 6 pax. Then is it safer to run 3 flights to move the 6 pax or one flight? One operation has exposure and the other has 3 times all the other many risks (which are also greater riskes than engine failure anyway). Obviously the t/o engine expose case is safer.
Don't expect to hear a logical reasoned counter arguement to this, instead watch the insults roll in
"is more of the same drum beating that AnFI has been bringing to the forum for way too long with his crusade to outlaw any more than one engine per helicopter. It is tedious, it is based on poor reasoning and is so predictable that it is bound to detract from any reasonable discussion where twin engine ops are raised on Rotorheads."
There's no material in there. The mods seem to accept this rude approach provided it is on the twin engine side of the 'discussion'.
As for your point about fare paying passengers and avoiding ditching etc, that is a different point, 2 engines in the cruise over a hostile surface when they are so poor at ditching has a natural attraction, especially in the NoTech mind of the 'bears'. (and I don't know, if you gave them the choice of the heli that can land safely on the water and the one that can't (but theoretically won't need to), maybe they would choose the safer one?)
The excess power to avoid exposure during t/o is a different discussion. There is simply no factual safety case for it AFAIK. It's hypothetical armchair layperson stuff, the kind of hypothetical that Crab doesn't like.
These NS machines seem to have a fairly poor record considering that they are flying the simplest type of flight (mostly autopilot cruise), loaded with safety aids, 2 commercial pilots, huge training / checking.
Crab: "his (AnFi) is a reasoned and coherent argument based purely on statistics" thanks
Crab: "The dismissal of ditching as an acceptable outcome is typical of someone who has spent little time over the water - especially in large sea states - and has never been dunker trained." I note that you are rightly not suggesting that is the case with me, merely that others also share this view. Obviously ditching is an acceptable outcome IMO when one's gearbox is on the way out for example, you don't think so?
(maybe I don't have oversea flying experience, ditching experience nor dunker training. Or maybe I do, but the logic is the point, not a discussion of your relatively limited experience)
If the risk of ditching were reduced to an acceptable level then twins would not need to waste payload on floats. In fact they ditch often enough to need to be good at it. (maybe better than they are)
Crab: "I for one don't trust statistics as anything other than an analysis of what has happened rather than a predictor of what might happen. " .... and Ronnie Regan used to consult astrologers but it's not a really sound way to design aircraft is it.
gmrwiz, I am sorry I really genuinely don't mean to be rude and I'd love to engage respectfully with you on the issues. As for your suggestion that being an AW salesman is an insult, I think that AW salesmen might be offended by that, AW salesmen have done a superb job and have been very succesful. I was just concerned that you were trying to suggest that prohibiting exposure during t/o had an obvious safety benefit, when it is the opinion of some of the most technically aware on this forum that it does not. (although it is not obvious, there are increased risks consequent from eliminating that one)
The reasoning requires more space than this forum allows but an example of one point is:
If a helicopter can be operated without exposure with 2 pax, but would be exposed with 6 pax. Then is it safer to run 3 flights to move the 6 pax or one flight? One operation has exposure and the other has 3 times all the other many risks (which are also greater riskes than engine failure anyway). Obviously the t/o engine expose case is safer.
Don't expect to hear a logical reasoned counter arguement to this, instead watch the insults roll in
Chief Bottle Washer
And I strongly suggest that when quoting other members then you include all their post without cherry picking and excluding such defining precursors as were used by crab@, but conveniently left out by you to make it appear that his statements in some way added veracity to your theories.
You have to look hard to find specific examples in the offshore world where an engine power loss during a critical phase of flight has been the primary cause of an accident in the recent past
It would appear that you were lucky
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SP thank you for the feedback, FWIW I say again here (as elsewhere) I think your moderation is excellent, and would not dream of 'berating you'. I thank you in advance for helping me to try and balance the discussion. Quite right about selectivity with Crab, but I didn't detect anything there except slur (that incidentally you know not to be true, and I was under the impression that there were more than one mod?)
I do try to stick to the point. Facts and well structured logic should work.
megan (thank you for debating the issue) indeed it is extra ordinary, and I can understand how you feel, but of course we have no choice but to live in a world of probability, the best we can do is optimise that for you.
So in the example below of moving the 6pax which of the 2 options would you be happiest with?
3 trips with 2 pax or 1 'exposed t/o' trip with the 6?
please could you/would you send me a link to the report on that incident as it is obviously an important 'data point'.
I do try to stick to the point. Facts and well structured logic should work.
megan (thank you for debating the issue) indeed it is extra ordinary, and I can understand how you feel, but of course we have no choice but to live in a world of probability, the best we can do is optimise that for you.
So in the example below of moving the 6pax which of the 2 options would you be happiest with?
3 trips with 2 pax or 1 'exposed t/o' trip with the 6?
please could you/would you send me a link to the report on that incident as it is obviously an important 'data point'.
If as a "plank" I may stop lurking for a second:
I'm bemused as well, there's no doubt most airliners spend the majority of their moving life in the cruise but I wouldn't by extension say that's the reason for 2 engines - I rather suspect that somebody's logic is flawed here.
AFAIK on the large commercial fixed wing side of things multiple engines are required to ensure a safe outcome for the flight in the event of an single engine failure. The regs don't specify a specific flight phase...the principle covers all stages of flight, including take-off - where despite all the 10 to the 9 stuff engine failures do still happen.
I don't know about you rotary guys but personally if I'm going to lose a donk (or even both) on a twin I'd actually much rather take the failure in the cruise rather than just after lift off with perhaps inhospitable terrain/built up area ahead...
Anyhow that's how I see it from my world, two engines is good for me and my passengers, etc, back to lurking..
the main reason why the 737 has 2 engines is for the enroute phase"
AFAIK on the large commercial fixed wing side of things multiple engines are required to ensure a safe outcome for the flight in the event of an single engine failure. The regs don't specify a specific flight phase...the principle covers all stages of flight, including take-off - where despite all the 10 to the 9 stuff engine failures do still happen.
I don't know about you rotary guys but personally if I'm going to lose a donk (or even both) on a twin I'd actually much rather take the failure in the cruise rather than just after lift off with perhaps inhospitable terrain/built up area ahead...
Anyhow that's how I see it from my world, two engines is good for me and my passengers, etc, back to lurking..
Last edited by wiggy; 17th Apr 2016 at 07:53.
I don't know about you rotary guys but personally if I'm going to lose a donk (or even both) on a twin I'd actually much rather take the failure in the cruise rather than just after lift off with perhaps inhospitable terrain/built up area ahead...
AnFi - this
.... and Ronnie Regan used to consult astrologers but it's not a really sound way to design aircraft is it.
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the thread is supposed to be about exposure for hv curve transit
not much material coming back on that?
the clear question is:
in the example below, moving the 6pax, which of the 2 options would you be happiest with?
3 trips with 2 pax or 1 'exposed t/o' trip with all 6?
what is your view on that wiggy, heli1, megan, crab ?
wiggy the maths isn't really the same for aeroplanes
in helicopters the engines have a common gearbox and common power delivery unlike the aeroplane
there are also more critical dynamic systems
the helicopter is able to land with significantly less kinetic energy than the 737
etc etc
I accept what heli1 says this is a simplistic argument and factors like the irrational beliefs of pax are material
crab I was merely pointing out that your dismissal of stats as damn lies etc (although understandable) is one of the material complexities of the issue ie "I don't care what the facts are I just know I feel better ... etc"
I don't think I am being rude to you am I?
There are exciting possibilities with asymetric engines for instance, having emergency power for just 2minutes, would give you the advantages of a single with the 'easy landing option' of spending 2 (or maybe 5?) minutes landing gently in the water (in the case of the NS). AB have some thoughts on this concept. Rules should be about the outcome required etc
not much material coming back on that?
the clear question is:
in the example below, moving the 6pax, which of the 2 options would you be happiest with?
3 trips with 2 pax or 1 'exposed t/o' trip with all 6?
what is your view on that wiggy, heli1, megan, crab ?
wiggy the maths isn't really the same for aeroplanes
in helicopters the engines have a common gearbox and common power delivery unlike the aeroplane
there are also more critical dynamic systems
the helicopter is able to land with significantly less kinetic energy than the 737
etc etc
I accept what heli1 says this is a simplistic argument and factors like the irrational beliefs of pax are material
crab I was merely pointing out that your dismissal of stats as damn lies etc (although understandable) is one of the material complexities of the issue ie "I don't care what the facts are I just know I feel better ... etc"
I don't think I am being rude to you am I?
There are exciting possibilities with asymetric engines for instance, having emergency power for just 2minutes, would give you the advantages of a single with the 'easy landing option' of spending 2 (or maybe 5?) minutes landing gently in the water (in the case of the NS). AB have some thoughts on this concept. Rules should be about the outcome required etc
When I gave up the business over a decade ago there were only two classifications, Cat A & B, none of the new Performance 1 etc.
The take off procedure laid down in our Ops Manual of the time implied guaranteed success from a failure at CDP on a platform take off, and this was backed up with sim training at West Palm, where no matter what numbers were dialled in, you were always able to fly away, providing you didn't do something absolutely stupid. But it took a conversation with an expert a few days ago to open my eyes that our procedure did not guarantee success, and his analysis was that the failure occurred a couple of seconds after CDP, which agreed with the copilots observation. Had it occurred at CDP, which was my impression, we would have impacted the deck edge. Who can guess the result of a helo freefalling 100 feet into the water, would we have incurred eleven fatalities? The industry would have sat up and took notice had that occurred I bet.
§29.63 Takeoff: Category B.
The horizontal distance required to take off and climb over a 50-foot obstacle must be established with the most unfavorable center of gravity. The takeoff may be begun in any manner if—
(a) The takeoff surface is defined;
(b) Adequate safeguards are maintained to ensure proper center of gravity and control positions; and
(c) A landing can be made safely at any point along the flight path if an engine fails.
Mention is made of momentary exposure in posts, how does that align with (c) above?
Or is it a case of regulations not keeping up with ingrained industry practices, as suggested in some posts?
The take off procedure laid down in our Ops Manual of the time implied guaranteed success from a failure at CDP on a platform take off, and this was backed up with sim training at West Palm, where no matter what numbers were dialled in, you were always able to fly away, providing you didn't do something absolutely stupid. But it took a conversation with an expert a few days ago to open my eyes that our procedure did not guarantee success, and his analysis was that the failure occurred a couple of seconds after CDP, which agreed with the copilots observation. Had it occurred at CDP, which was my impression, we would have impacted the deck edge. Who can guess the result of a helo freefalling 100 feet into the water, would we have incurred eleven fatalities? The industry would have sat up and took notice had that occurred I bet.
§29.63 Takeoff: Category B.
The horizontal distance required to take off and climb over a 50-foot obstacle must be established with the most unfavorable center of gravity. The takeoff may be begun in any manner if—
(a) The takeoff surface is defined;
(b) Adequate safeguards are maintained to ensure proper center of gravity and control positions; and
(c) A landing can be made safely at any point along the flight path if an engine fails.
Mention is made of momentary exposure in posts, how does that align with (c) above?
Or is it a case of regulations not keeping up with ingrained industry practices, as suggested in some posts?
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one is aircraft certification and the other is operating manner
'safe landing' does not mean 'does not crash'
which hypothetical case do you prefer for the 6 pax to be moved? - exposure can be safer
JimL is the expert at this field, nobody else understands it as he does. The mess he is trying to sort is made by people that dont understand it.
Of course if a 'safe profile' is flown then the HV curve should not apply, since there is 'accountability', but there is the question of interpretation between at least the USA, EU, ICAO, and the analysis of risk has historically been a little dodgy (eg you can't meaningfully square 1x10^-5) and seems to make you and crab distrustful of the stats
best wishes
'safe landing' does not mean 'does not crash'
which hypothetical case do you prefer for the 6 pax to be moved? - exposure can be safer
JimL is the expert at this field, nobody else understands it as he does. The mess he is trying to sort is made by people that dont understand it.
Of course if a 'safe profile' is flown then the HV curve should not apply, since there is 'accountability', but there is the question of interpretation between at least the USA, EU, ICAO, and the analysis of risk has historically been a little dodgy (eg you can't meaningfully square 1x10^-5) and seems to make you and crab distrustful of the stats
best wishes
Last edited by AnFI; 18th Apr 2016 at 07:32.
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Or is it a case of regulations not keeping up with ingrained industry practices, as suggested in some posts?
The NPA has been issued only to try to fix an operational issue through a bureaucratic approach and the possible revision of the basic regulation, if any, will never add any safety to these kind of operations.
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AnFI
in the example below, moving the 6pax, which of the 2 options would you be happiest with?
3 trips with 2 pax or 1 'exposed t/o' trip with all 6?
I think that this case is not appropriate. A 6 passengers helicopter is a Part 27 and HV is performance information.
More appropriate is the case of a 20 passengers helicopter:
Carrying 20 pax require exposure while with 15 pax you can fly PC1 procedure . Which one do you choose? I have no doubt : 15 pax.
in the example below, moving the 6pax, which of the 2 options would you be happiest with?
3 trips with 2 pax or 1 'exposed t/o' trip with all 6?
I think that this case is not appropriate. A 6 passengers helicopter is a Part 27 and HV is performance information.
More appropriate is the case of a 20 passengers helicopter:
Carrying 20 pax require exposure while with 15 pax you can fly PC1 procedure . Which one do you choose? I have no doubt : 15 pax.