Cheyenne II Handling
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Cheyenne II Handling
Started this post so I wouldn't hijack the other post relating to the Cheyenne II.
Ramjager was saying how good this thing was to fly in CAVOK conditions but terrible in bad visibility.
Wonder if someone can explain how handling characteristics change due to Visibility.
Ramjager was saying how good this thing was to fly in CAVOK conditions but terrible in bad visibility.
Wonder if someone can explain how handling characteristics change due to Visibility.
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Hi Woomera this post of mine has obviously offended some and I concede that the timing was probably wrong. As this was not my intention I ask that you delete this post as I am not familiar with the process.
Moderator
The accident thread (and this also) makes comments about stability considerations and SAS kit.
I have only had the one flight exposure to the Cheyenne quite some years ago (can't recall now whether a 1 or 2) and, from that short observation (which was strictly qualitative), it appeared to be a not unreasonable platform.
While I don't have specific knowledge of the system in this series of aircraft, I think I have a handle on the basics of problem and solution ... can I enquire of those with detailed Type-specific knowledge what the perceived deficiencies in the SAS on this aircraft might be ?
I think that, provided the thread doesn't venture into speculation regarding the recent accident and is sensitive to the feelings of those who have been touched by the deaths (and there will be many of us who knew the pilot over the years), then there may be some value in the discussion.
I have only had the one flight exposure to the Cheyenne quite some years ago (can't recall now whether a 1 or 2) and, from that short observation (which was strictly qualitative), it appeared to be a not unreasonable platform.
While I don't have specific knowledge of the system in this series of aircraft, I think I have a handle on the basics of problem and solution ... can I enquire of those with detailed Type-specific knowledge what the perceived deficiencies in the SAS on this aircraft might be ?
I think that, provided the thread doesn't venture into speculation regarding the recent accident and is sensitive to the feelings of those who have been touched by the deaths (and there will be many of us who knew the pilot over the years), then there may be some value in the discussion.
Last edited by john_tullamarine; 30th Jul 2004 at 03:38.
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assymetric
Thank you for your consideration in creating a separate thread.
No problems and a legitimate question, which we may be discussed here.
I am happy to let this discussion continue, for its educational content as long as it is instructive, constructive and does not cross over into morbid speculation on the cause of the recent accident.
It may in fact trigger some thoughts from those who may have flown the type.
If you do have any direct evidence or constructive input on the accident, they should be adressed to the ATSB, they encourage your participation will be most appreciative.
Alan Stray - Deputy Director, Air Safety
Switchboard - Communications and Information
Tel: (02) 6274 6141 (BH) or 1800 020 616 (BH)
Email: [email protected] Fax: (02) 6247 3117
Postal Address
PO Box 967
Civic Square ACT 2608
AUSTRALIA.
Thank you for your consideration in creating a separate thread.
No problems and a legitimate question, which we may be discussed here.
I am happy to let this discussion continue, for its educational content as long as it is instructive, constructive and does not cross over into morbid speculation on the cause of the recent accident.
It may in fact trigger some thoughts from those who may have flown the type.
If you do have any direct evidence or constructive input on the accident, they should be adressed to the ATSB, they encourage your participation will be most appreciative.
Alan Stray - Deputy Director, Air Safety
Switchboard - Communications and Information
Tel: (02) 6274 6141 (BH) or 1800 020 616 (BH)
Email: [email protected] Fax: (02) 6247 3117
Postal Address
PO Box 967
Civic Square ACT 2608
AUSTRALIA.
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Ramjager may have a point in regard to the "handling characteristics" rather than whether it is CAVOK or not.
Stability or lack off is a function of the design and certification requirements not the weather conditions. A visit to the FAA site and FAR23 Certification requirements in regard to static and dynamic stability is instructive.
The weather conditions i.e. IMC and turbulence may simply exacerbate a marginal or non-optimal handling issue, which may be just a "nuisance" requiring more attention than is usual in severe clear, but becomes a real problem in a high workload situation.
If the stability is marginal and/or has the capacity to become even mildly divergent in some circumstances, then it's big trouble in River City and Pontius himself will be praying to his God.
This particular type did not have a happy time in certification in regard to aft C of G and stabiltiy in this axis, without the aid of a Stability Augmentation Sytsem and there was some controversy surrounding the certification data supplied in regard to the flight testing.
Stability Augmentation Systems (SAS) are not at all unusual and may appear in some form or the other in aircraft design including the modern ones to enable the designers to optimise efficiency by reducing several forms of drag inherent in designing the aircraft that meet the stability requirements without them.
Or;
to "fix" a basic design inadequacy that may arise when an airframe is stretched or powered beyond the original design parameters.
There comes a point when it is simpler/cheaper/more efficient to start all over again, if you can afford to.
In the former case modern FAR25, transport category designs either, have redundancy (double ir triple) or become "no go" despatch items or if they are not serviceable, operational limits, in regard to loads, speeds and altitudes, are applied to mitigate the adverse effects.
Pumping fuel around is another useful tool.
The latter case usually in FAR23 aircraft may simply be a non redundant "no go" item and you are on your own should it fail in flight.
Do some research for example on "inertia coupling".
D. P Davies "Handling the Big Jets" is very instructive. The title is a tad misleading, because it is actually a really great "primer" for any student of aerodynamics. The UK CAA for whom he was "the man" in this regard were often critical/required fixes/or downright refused to certify in their, country some of the airframes presented for certification.
There concerns were usually borne out by the accident history of these types.
The certification process and requirements have evolved over a long period of time and the incorporate the manifold lessons from accidents and research of this time.
Many, many aircraft in service today, would not get a C of A today were they to apply, against the current requirements.
The requirements are deceptively simple;
To provide the maximum possible protection the pax;
and;
Enable an averagely competent pilot to keep it together, in all but the most extreme circumstances, without having to be Biggles/Capt Hero/Hop Harrigan combined.
I have been known to upset some pilots when I suggest that it should be possible for your granny to fly it without too much fuss.
.
And without stepping on any professional egos'
, isn't that, after all, what we need when we are trying to manage a difficult approach in dodgy weather.
Stability or lack off is a function of the design and certification requirements not the weather conditions. A visit to the FAA site and FAR23 Certification requirements in regard to static and dynamic stability is instructive.
The weather conditions i.e. IMC and turbulence may simply exacerbate a marginal or non-optimal handling issue, which may be just a "nuisance" requiring more attention than is usual in severe clear, but becomes a real problem in a high workload situation.
If the stability is marginal and/or has the capacity to become even mildly divergent in some circumstances, then it's big trouble in River City and Pontius himself will be praying to his God.
This particular type did not have a happy time in certification in regard to aft C of G and stabiltiy in this axis, without the aid of a Stability Augmentation Sytsem and there was some controversy surrounding the certification data supplied in regard to the flight testing.
Stability Augmentation Systems (SAS) are not at all unusual and may appear in some form or the other in aircraft design including the modern ones to enable the designers to optimise efficiency by reducing several forms of drag inherent in designing the aircraft that meet the stability requirements without them.
Or;
to "fix" a basic design inadequacy that may arise when an airframe is stretched or powered beyond the original design parameters.
There comes a point when it is simpler/cheaper/more efficient to start all over again, if you can afford to.
In the former case modern FAR25, transport category designs either, have redundancy (double ir triple) or become "no go" despatch items or if they are not serviceable, operational limits, in regard to loads, speeds and altitudes, are applied to mitigate the adverse effects.
Pumping fuel around is another useful tool.
The latter case usually in FAR23 aircraft may simply be a non redundant "no go" item and you are on your own should it fail in flight.
Do some research for example on "inertia coupling".
D. P Davies "Handling the Big Jets" is very instructive. The title is a tad misleading, because it is actually a really great "primer" for any student of aerodynamics. The UK CAA for whom he was "the man" in this regard were often critical/required fixes/or downright refused to certify in their, country some of the airframes presented for certification.
There concerns were usually borne out by the accident history of these types.
The certification process and requirements have evolved over a long period of time and the incorporate the manifold lessons from accidents and research of this time.
Many, many aircraft in service today, would not get a C of A today were they to apply, against the current requirements.
The requirements are deceptively simple;
To provide the maximum possible protection the pax;
and;
Enable an averagely competent pilot to keep it together, in all but the most extreme circumstances, without having to be Biggles/Capt Hero/Hop Harrigan combined.
I have been known to upset some pilots when I suggest that it should be possible for your granny to fly it without too much fuss.
.And without stepping on any professional egos'
, isn't that, after all, what we need when we are trying to manage a difficult approach in dodgy weather.
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Woomera
Moderator
My observations on the other thread were meant to be constructive and informative. They were not intended to touch any raw nerves.
My understanding is that PPRuNe professes to be a forum for the benefit of professional and associated aviation persons and not a suitable location for the posting of eulogies and laments for our departed aviators and their pax. There will not be one of us who is not profoundly upset and saddened by the recent losses in Australia and PNG. If any of those close to the victims happen upon these posts they will certainly feel our collective grief and then go on to appreciate any endeavors we professionals may then go on to make towards the avoidance of similar occurrences. Our younger generations of aviators are forever on a learning curve which at times must appear to be quite steep. They are the ones who can and should learn as much as possible from such events.
So Mr Moderator I would recommend that you now give free reign to this thread or another of your choosing to permit the posting of observations and opinions on any aspect of these or similar avoidables/accidents. To wait for the ponderous progress of the formal investigations which already promise to be inconclusive will prevent or stifle lessons waiting to be learned. We all earnestly hope that the causes were not pilot errors but both pilots would say if it were and if they could, "Learn from my mistake/s."
My own extensive experience and findings as a military aircraft accident/incident investigator has led to safer aircraft and aircraft operations and a recognition of the benefits to be derived from the lessons learned. I continue to deplore the time being taken for the revelation of the means by which the crew of that stricken DHL A300 managed to recover at Baghdad many moons ago. We still have much to learn from that extraordinary feat.
gaunty
What did "inertia coupling" have to do with your subject discussions?
The most common problem with inertia coupling occurs with heavy highly manoeuverable aircraft having a high rate of roll which when continued through several revolutions cross couples into increasing pitching as the rolling continues. The divergence can rapidly become dangerous and then terminal. Fly by wire controls are normally able to dampen down the coupling. There will usually be various degrees of inertial coupling in spins. For most other manoeuvres the effects are negligible. Please correct me if there are other significant cases. Would like to know whether aerobatic pilots come across significant cross coupling during max rate manoeuvres.
Did a double-take, gaunty, on your statement that something, not clearly defined, in your post --
--------------------------------------------------
Enables an averagely competent pilot to keep it together, in all but the most extreme circumstances, without having to be Biggles/Capt Hero/Hop Harrigan combined.
--------------------------------------------------
That means that half of the pilots on the bottom side of average will not be able to hack it. WRONG. Your next sentence is closer to the truth.
We test pilots and the regulatory authorities have a heavy responsibility for the determination of the acceptable limits of aircraft operation and handling with a reasonable expectation that the least proficient pilots accepted into the system will be able to fly safely. This in turn places a responsibility on chief flying instructors and then on up the line to check captains and proficiency supervisors to eliminate those who can't make the lower levels of acceptability.
Moderator
My observations on the other thread were meant to be constructive and informative. They were not intended to touch any raw nerves.
My understanding is that PPRuNe professes to be a forum for the benefit of professional and associated aviation persons and not a suitable location for the posting of eulogies and laments for our departed aviators and their pax. There will not be one of us who is not profoundly upset and saddened by the recent losses in Australia and PNG. If any of those close to the victims happen upon these posts they will certainly feel our collective grief and then go on to appreciate any endeavors we professionals may then go on to make towards the avoidance of similar occurrences. Our younger generations of aviators are forever on a learning curve which at times must appear to be quite steep. They are the ones who can and should learn as much as possible from such events.
So Mr Moderator I would recommend that you now give free reign to this thread or another of your choosing to permit the posting of observations and opinions on any aspect of these or similar avoidables/accidents. To wait for the ponderous progress of the formal investigations which already promise to be inconclusive will prevent or stifle lessons waiting to be learned. We all earnestly hope that the causes were not pilot errors but both pilots would say if it were and if they could, "Learn from my mistake/s."
My own extensive experience and findings as a military aircraft accident/incident investigator has led to safer aircraft and aircraft operations and a recognition of the benefits to be derived from the lessons learned. I continue to deplore the time being taken for the revelation of the means by which the crew of that stricken DHL A300 managed to recover at Baghdad many moons ago. We still have much to learn from that extraordinary feat.
gaunty
What did "inertia coupling" have to do with your subject discussions?
The most common problem with inertia coupling occurs with heavy highly manoeuverable aircraft having a high rate of roll which when continued through several revolutions cross couples into increasing pitching as the rolling continues. The divergence can rapidly become dangerous and then terminal. Fly by wire controls are normally able to dampen down the coupling. There will usually be various degrees of inertial coupling in spins. For most other manoeuvres the effects are negligible. Please correct me if there are other significant cases. Would like to know whether aerobatic pilots come across significant cross coupling during max rate manoeuvres.
Did a double-take, gaunty, on your statement that something, not clearly defined, in your post --
--------------------------------------------------
Enables an averagely competent pilot to keep it together, in all but the most extreme circumstances, without having to be Biggles/Capt Hero/Hop Harrigan combined.
--------------------------------------------------
That means that half of the pilots on the bottom side of average will not be able to hack it. WRONG. Your next sentence is closer to the truth.
We test pilots and the regulatory authorities have a heavy responsibility for the determination of the acceptable limits of aircraft operation and handling with a reasonable expectation that the least proficient pilots accepted into the system will be able to fly safely. This in turn places a responsibility on chief flying instructors and then on up the line to check captains and proficiency supervisors to eliminate those who can't make the lower levels of acceptability.
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Milt
We did not intend to suggests that your observations were out of line ot touched any raw nerves and concur absolutely with your thoughts on the educational aspects for all of us in the discussion and informed debate of the issues surrounding an accident and PPRuNe has hosted many many of these over the years.
There has in fact been "evidence" revealed that has assisted the authorities and aviation organisations review processes and procedures.
Danny and Rob the co owners of the site and many of our moderators sit on many regulatory and industry safety boards and comittees, we are collectively committed to making PPRuNe the premier international safety portal for the industry.
Where there are very well known individuals it has been the custom from time to time to separate the condolences from the sometimes vigorous and controversial debate about its cause.
It's a difficult call and we would certainly welcome your experience and input in achieving our aims.
We also recognise that nobody "owns" ideas or that some might not have the "right experience or detailed knowledge" it is sufficient that inteligent questions asked and answered or "intutitive" assertions are made that can be either examined, spark another line of hitherto ignored thought or an entirely new but fascinating discussion.
We wish we could collate some of the more interesting threads into books or digests for the amount of knowlege, wisdom and experience conatined in them in a manner not ordinarily possible.
Sadly the quality of some of this debate has been in D & G any rate diverted by other important local issues such as the NAS amongst other things.
This accident raises a number of very germane issues, being an interface between the current modern and old technology concepts and philosophies.
We've been there before and unforunately, it seems we need to revisit the subject.
Once again we welcome your experience and input in achieving our mutual aims.
We did not intend to suggests that your observations were out of line ot touched any raw nerves and concur absolutely with your thoughts on the educational aspects for all of us in the discussion and informed debate of the issues surrounding an accident and PPRuNe has hosted many many of these over the years.
There has in fact been "evidence" revealed that has assisted the authorities and aviation organisations review processes and procedures.
Danny and Rob the co owners of the site and many of our moderators sit on many regulatory and industry safety boards and comittees, we are collectively committed to making PPRuNe the premier international safety portal for the industry.
Where there are very well known individuals it has been the custom from time to time to separate the condolences from the sometimes vigorous and controversial debate about its cause.
It's a difficult call and we would certainly welcome your experience and input in achieving our aims.
We also recognise that nobody "owns" ideas or that some might not have the "right experience or detailed knowledge" it is sufficient that inteligent questions asked and answered or "intutitive" assertions are made that can be either examined, spark another line of hitherto ignored thought or an entirely new but fascinating discussion.
We wish we could collate some of the more interesting threads into books or digests for the amount of knowlege, wisdom and experience conatined in them in a manner not ordinarily possible.
Sadly the quality of some of this debate has been in D & G any rate diverted by other important local issues such as the NAS amongst other things.
This accident raises a number of very germane issues, being an interface between the current modern and old technology concepts and philosophies.
We've been there before and unforunately, it seems we need to revisit the subject.
Once again we welcome your experience and input in achieving our mutual aims.
Don Quixote Impersonator
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Milt
I suspect we are in heated agreement about most things contained in my post, just coming from different directions.
No I am not a "test pilot" but I am more than a little familiar with the process and production and maintenance test flying and the technical aspects of flight.
What does "inertia coupling" have to do with my subject discussions?
Both, not much and a lot.
Not much as it was intended as a challenge was to those who had not heard of the term to go find out about it and, hopefully, learn a whole lot more about other things aerodynamic on the way. It is not normally included your average principles of flight syllabus. For you or I to explicate the principle is the easy way out for them but we might well do so in the ensuing discussion, which is where the real value lays for us all.
We all learn something new.
And a lot; sadly and enviously
most of us have not had the pleasure of dealing with
although as a devoted coward, you can have the
all on your own. 
Nonetheless it is a design problem for those GA types that have evolved from the pedestrian un-pressurised, low speed piston version to pressurised higher speed turbines or the stretching of a smaller design into something it didn¡¦t start out to be.
It's the TAS v IAS thing. Forgive me if I appear to be teaching you to suck eggs I would not be so impertinent, but I am also talking an audience who may not like yourself have been there.
If we start say with a 2,550 lb piston engine, airframe, wing combination and evolve it through the years to a 12,500 lb turboprop, pressurised, airframe and substantially the same wing, there are a few aerodynamic issues to be dealt with along the way.
You will however wind up with big compromises and entirely legitimate "trick fixes" along the way. An extreme example for certain, but sustainable for the basis of this discussion. If you don¡'t get this and/or your marketing right you are for the high jump as most manufacturers who went this route went.
It can be made to and will work but eventually you get to the point where it is more efficient to start from scratch.
Start with a 6,200 lb piston design that is already "overweight" from the original calculations with acceptable but at the edge of the longitudinal stability requirements, but all in all a top aircraft doing what it was designed to do very well. Along come your competitors with a better idea, you don't have the money to start a new certification from scratch so lets clap some turbines (lighter but C of G problem exacerbated and higher power to weight ratio) on it, pressurise it (heavier but we have the turbine bonus), faster (operates closer to VNO/VMO so not much real TAS benefit unless we operate "up there" ) can operate "up there" to get the TAS benefit, but we are still using the same control surface area to "control" a whole lot more momentum at say the same IAS, what may have not been, now becomes "uncomfortable wandering about" to the pilot/pax as the aircraft or pilot tries "keep stable" or, divergent. A gross disturbance, an out of trim or just plain old autopilot disconnect with some old fashioned ham fistedness can intiate an "interesting series of unwelcome gyrations". The same technique (not hamfistedness) used in test flying, stabilize the aircraft in a trimmed condition, provoke a reaction with a defined input and see what happens, continuously pushing the performance boundaries until you find the edge. Whooooooooah there pardner.
Bigger control surfaces to solve this problem at altitude, (and which work against us at low altitude) are either a recertification and/or weight/drag problem, so we either limit the IAS at altitude or we help the pilot with a automatic system. Let¡'s not complicate the problem with Mach issues for the moment.
The yaw damper "option" on some GA types is a welcome addition to those down the back for when it gets bumpy.
You might even have the situation where the "automatic system" be it "yaw damper" or SAS (a more sophisticated multiaxis damper) is a requirement for all flight regimes.
All of the GA types including King Air are living on "grandfathered" certifications of the original barely recognizable types , the world has moved on with tougher certification requirements much as it would not be possible to get a compliance plate were we to resubmit the FJ Holden. Likewise with transport category aircraft.
Fly by wire is a designers dreams come true.
He/she can design, with enough redundancy to satisfy the regulators or the military, a very fuel/drag/maneuverability efficient but otherwise fatally "unstable" airframe and "tune it up" so the average pilot can still "handle" it.
The Airbus/Boeing control authority "war" continues but will IMHO eventually merge.
Designers of yore and that includes the GA types under discussion did not then, but now have this luxury.
I am trying to think of a more elegant way of expressing it and you may be able to help me, but I am concerned that there has been a transposition/transference of modern ideas/concepts on to "looks modern" but is very old technology equipment.
The old pressurization systems usually have rubber hoses beyond the pressurization source or sonic venturi and hot bits. Who has checked their 30 year old system from end to end lately, I know I'd think twice about a 30 year old condom. A recent coronial revealed there was no maintenance inspection requirement for component parts of a popular turboprop, not required by the manufacturer so not required by the regulator. It is now The manufacturer in his wildest dreams never imagined the aircraft, nor designed it so would still be flying nearly 30,000 hours and 30 years on.
Might have been a bit careless with syntax?, delete "averagely", I was only trying to illustrate a point. But you know what I mean, you should not have to be able to fly at "test pilot" level 24/7 to keep the folks in the back safe.
I hope that you will agree that the "knowledge" syllabus especially for CPL/ATPL is not nearly comprehensive enough to provide the background required.
Or do we leave it to and we now IMHO can with modern types leave it the designers/test pilots and computers.
But what do we do in the meantime until the oldies are retired out of the system.
edited for fomatting from Word to UBB
I suspect we are in heated agreement about most things contained in my post, just coming from different directions.
No I am not a "test pilot" but I am more than a little familiar with the process and production and maintenance test flying and the technical aspects of flight.
What does "inertia coupling" have to do with my subject discussions?
Both, not much and a lot.
Not much as it was intended as a challenge was to those who had not heard of the term to go find out about it and, hopefully, learn a whole lot more about other things aerodynamic on the way. It is not normally included your average principles of flight syllabus. For you or I to explicate the principle is the easy way out for them but we might well do so in the ensuing discussion, which is where the real value lays for us all.
We all learn something new.
And a lot; sadly and enviously
most of us have not had the pleasure of dealing with
heavy highly manoeuverable aircraft having a high rate of roll which when continued through several revolutions cross couples into increasing pitching as the rolling continues
although as a devoted coward, you can have the
The divergence can rapidly become dangerous and then terminal.
Nonetheless it is a design problem for those GA types that have evolved from the pedestrian un-pressurised, low speed piston version to pressurised higher speed turbines or the stretching of a smaller design into something it didn¡¦t start out to be.
It's the TAS v IAS thing. Forgive me if I appear to be teaching you to suck eggs I would not be so impertinent, but I am also talking an audience who may not like yourself have been there.
If we start say with a 2,550 lb piston engine, airframe, wing combination and evolve it through the years to a 12,500 lb turboprop, pressurised, airframe and substantially the same wing, there are a few aerodynamic issues to be dealt with along the way.
You will however wind up with big compromises and entirely legitimate "trick fixes" along the way. An extreme example for certain, but sustainable for the basis of this discussion. If you don¡'t get this and/or your marketing right you are for the high jump as most manufacturers who went this route went.
It can be made to and will work but eventually you get to the point where it is more efficient to start from scratch.
Start with a 6,200 lb piston design that is already "overweight" from the original calculations with acceptable but at the edge of the longitudinal stability requirements, but all in all a top aircraft doing what it was designed to do very well. Along come your competitors with a better idea, you don't have the money to start a new certification from scratch so lets clap some turbines (lighter but C of G problem exacerbated and higher power to weight ratio) on it, pressurise it (heavier but we have the turbine bonus), faster (operates closer to VNO/VMO so not much real TAS benefit unless we operate "up there" ) can operate "up there" to get the TAS benefit, but we are still using the same control surface area to "control" a whole lot more momentum at say the same IAS, what may have not been, now becomes "uncomfortable wandering about" to the pilot/pax as the aircraft or pilot tries "keep stable" or, divergent. A gross disturbance, an out of trim or just plain old autopilot disconnect with some old fashioned ham fistedness can intiate an "interesting series of unwelcome gyrations". The same technique (not hamfistedness) used in test flying, stabilize the aircraft in a trimmed condition, provoke a reaction with a defined input and see what happens, continuously pushing the performance boundaries until you find the edge. Whooooooooah there pardner.
Bigger control surfaces to solve this problem at altitude, (and which work against us at low altitude) are either a recertification and/or weight/drag problem, so we either limit the IAS at altitude or we help the pilot with a automatic system. Let¡'s not complicate the problem with Mach issues for the moment.
The yaw damper "option" on some GA types is a welcome addition to those down the back for when it gets bumpy.
You might even have the situation where the "automatic system" be it "yaw damper" or SAS (a more sophisticated multiaxis damper) is a requirement for all flight regimes.
All of the GA types including King Air are living on "grandfathered" certifications of the original barely recognizable types , the world has moved on with tougher certification requirements much as it would not be possible to get a compliance plate were we to resubmit the FJ Holden. Likewise with transport category aircraft.
Fly by wire is a designers dreams come true.
He/she can design, with enough redundancy to satisfy the regulators or the military, a very fuel/drag/maneuverability efficient but otherwise fatally "unstable" airframe and "tune it up" so the average pilot can still "handle" it.
The Airbus/Boeing control authority "war" continues but will IMHO eventually merge.
Designers of yore and that includes the GA types under discussion did not then, but now have this luxury.
I am trying to think of a more elegant way of expressing it and you may be able to help me, but I am concerned that there has been a transposition/transference of modern ideas/concepts on to "looks modern" but is very old technology equipment.
The old pressurization systems usually have rubber hoses beyond the pressurization source or sonic venturi and hot bits. Who has checked their 30 year old system from end to end lately, I know I'd think twice about a 30 year old condom. A recent coronial revealed there was no maintenance inspection requirement for component parts of a popular turboprop, not required by the manufacturer so not required by the regulator. It is now The manufacturer in his wildest dreams never imagined the aircraft, nor designed it so would still be flying nearly 30,000 hours and 30 years on.
That means that half of the pilots on the bottom side of average will not be able to hack it. WRONG.
I hope that you will agree that the "knowledge" syllabus especially for CPL/ATPL is not nearly comprehensive enough to provide the background required.
Or do we leave it to and we now IMHO can with modern types leave it the designers/test pilots and computers.
But what do we do in the meantime until the oldies are retired out of the system.
edited for fomatting from Word to UBB
Last edited by gaunty; 3rd Aug 2004 at 04:38.
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gaunty
We seem to have our wires crossed on the subject of "Inertia Coupling".
You seem to be using the term somehow in relation to the evolution of a generation of GA aircraft (Cheyenne included) whereas my Inertia Coupling, sometimes called Roll Coupling. concerns the deterioration in aircraft stability that can result when some high speed and highly manoeuvrable aircraft are rolled through a succession of rolls. If such aircraft have fore and aft mass outside the axis of roll then such mass being rotated around the axis will be flung (centrifugally) away from the roll axis resulting in increasing pitching as the roll continues. No one, it seems, has ever tried with any success to use flying controls to counteract the divergent pitching which can rapidly become quite violent.
Perhaps it would be of interest to introduce a new thread on Inertia/Roll Coupling and then I would find it fascinating to kick off other unusuals such as JCs (PIOs - Pilot Induced Oscillations), Flutter, Control Configured Vehicles, Coffins Corner, Artificial Feel Systems, Stick Force per g, Control Harmony, Break-out Forces, Rudder Over Balance, Lateral Centre of Pressure, Cruise Climb and similar subjects which generally lie on the periphery of the average fixed wing pilot's knowledge and or experience and or comprehension.
PPRuNe's addicts are such an interesting bunch; the various views and angles that emerge from the woodwork are precious.
We seem to have our wires crossed on the subject of "Inertia Coupling".
You seem to be using the term somehow in relation to the evolution of a generation of GA aircraft (Cheyenne included) whereas my Inertia Coupling, sometimes called Roll Coupling. concerns the deterioration in aircraft stability that can result when some high speed and highly manoeuvrable aircraft are rolled through a succession of rolls. If such aircraft have fore and aft mass outside the axis of roll then such mass being rotated around the axis will be flung (centrifugally) away from the roll axis resulting in increasing pitching as the roll continues. No one, it seems, has ever tried with any success to use flying controls to counteract the divergent pitching which can rapidly become quite violent.
Perhaps it would be of interest to introduce a new thread on Inertia/Roll Coupling and then I would find it fascinating to kick off other unusuals such as JCs (PIOs - Pilot Induced Oscillations), Flutter, Control Configured Vehicles, Coffins Corner, Artificial Feel Systems, Stick Force per g, Control Harmony, Break-out Forces, Rudder Over Balance, Lateral Centre of Pressure, Cruise Climb and similar subjects which generally lie on the periphery of the average fixed wing pilot's knowledge and or experience and or comprehension.
PPRuNe's addicts are such an interesting bunch; the various views and angles that emerge from the woodwork are precious.
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Milt
Probably, we are a world divided by a common language, I suspect whilst we might not be on the same page we may be in the same chapter.
High speed, heavy, highly manouvreable aircaft are outside my experience, although I would give my left one (actually either or both would do, as at my age its academic ) to strap one on and go have a poke around the envelope.
Spot on and please lead on, we haven't had a good technical "stoush"
around here for a while.
We can all teach and learn from each other.
Just finished Brysons "A short history of just about everything", which I know you would enjoy, wherein one of the points he makes is that progress is sometimes difficult when ideas and concepts developed in different areas of the same subject, get different "names".
The soting out process often gets slowed down or even derailed by egos or even nationalistic fervour and prejudice.
Isn't the internet great.
bushy hang in there, if you cant teach us anything, you may well learn something beyond aero club bar prejudices.
Probably, we are a world divided by a common language, I suspect whilst we might not be on the same page we may be in the same chapter.
High speed, heavy, highly manouvreable aircaft are outside my experience, although I would give my left one (actually either or both would do, as at my age its academic ) to strap one on and go have a poke around the envelope.
Perhaps it would be of interest to introduce a new thread on Inertia/Roll Coupling and then I would find it fascinating to kick off other unusuals such as JCs (PIOs - Pilot Induced Oscillations), Flutter, Control Configured Vehicles, Coffins Corner, Artificial Feel Systems, Stick Force per g, Control Harmony, Break-out Forces, Rudder Over Balance, Lateral Centre of Pressure, Cruise Climb and similar subjects which generally lie on the periphery of the average fixed wing pilot's knowledge and or experience and or comprehension.
Spot on and please lead on, we haven't had a good technical "stoush"
around here for a while.We can all teach and learn from each other.
Just finished Brysons "A short history of just about everything", which I know you would enjoy, wherein one of the points he makes is that progress is sometimes difficult when ideas and concepts developed in different areas of the same subject, get different "names".
The soting out process often gets slowed down or even derailed by egos or even nationalistic fervour and prejudice.
Isn't the internet great.
bushy hang in there, if you cant teach us anything, you may well learn something beyond aero club bar prejudices.
Moderator
.. I know I saw a Miracle at Ballarat (airshow) some years ago, as part of his routine, run some twinkle rolls at low altitude (no .. too low to call it altitude .. but he was a little bit above head height .. on one run down the runway, he ran three rolls and the nose dropped during the last. Looked somewhere between frightening and terrifying to me ... I only ever had the one ride in a Mirage and the roll rate was ... impressive is probably too inadequate a word ...
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john_tullamarine
Re Inertia Coupling.
The Mirage III was/is perhaps the most susceptible aircraft to the effects of inertia coupling that I know of but there well may be others out there. Some further discussion may even go some way to preventing further disasters.
Had first hand experience with two RAAF losses (one pilot) resulting directly from this instability.
Will soon start another thread on subject and describe in introduction.
Re Inertia Coupling.
The Mirage III was/is perhaps the most susceptible aircraft to the effects of inertia coupling that I know of but there well may be others out there. Some further discussion may even go some way to preventing further disasters.
Had first hand experience with two RAAF losses (one pilot) resulting directly from this instability.
Will soon start another thread on subject and describe in introduction.
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Cheyenne Crash
Let us learn from a PPRuNe analysis of facts as generally known about the crash of the Cheyenne in Victoria recently whilst the circumstances are still somewhat fresh. It matters not whether we run off on tangents as each will have its own value to those who can benefit from the experiences of others. Facts may even emerge which may assist in the formal investigation which on the face of it may only come up with a list of possibilities.
Having seen first hand the type of weather conditions at the time one cannot discount the weather. It has to be the primary factor which led to the crash.
The Moderator should be able to keep any tangent of discussion within bounds or have legal or other reasons why we should not head down this path.
---------------------------------------------
A typical set of abbreviated Terms of Reference for an inquiry could be :-
Aircraft, Engines and Equipment
Records
Servicing
Flight characteristics
Equipment fitted and known performance.
Pilot
Experience - past and recent
Licencing
Instrument flying records
Previous IMC and visual approaches to Benalla
Flight Plan and Actual
Met forecast and Met actual
ATC and communications
Nav aids available and used
Maps and publications on board.
Ground Observations
Clues from wreckage
Location and terrain in area
Witnesses - Conditions of flight observed
Crash site investigation
Heading on impact
Determine whether any of the following are relevant.
Engine failure: Low flying: Medical: GPS failure: Nav system fail: Flight Inst fail: Flight control fail: Structural fail: Way point error: Fuel: Loss of control: Sabotage
------------------------------------
Bound to be others to emerge.
Let us learn from a PPRuNe analysis of facts as generally known about the crash of the Cheyenne in Victoria recently whilst the circumstances are still somewhat fresh. It matters not whether we run off on tangents as each will have its own value to those who can benefit from the experiences of others. Facts may even emerge which may assist in the formal investigation which on the face of it may only come up with a list of possibilities.
Having seen first hand the type of weather conditions at the time one cannot discount the weather. It has to be the primary factor which led to the crash.
The Moderator should be able to keep any tangent of discussion within bounds or have legal or other reasons why we should not head down this path.
---------------------------------------------
A typical set of abbreviated Terms of Reference for an inquiry could be :-
Aircraft, Engines and Equipment
Records
Servicing
Flight characteristics
Equipment fitted and known performance.
Pilot
Experience - past and recent
Licencing
Instrument flying records
Previous IMC and visual approaches to Benalla
Flight Plan and Actual
Met forecast and Met actual
ATC and communications
Nav aids available and used
Maps and publications on board.
Ground Observations
Clues from wreckage
Location and terrain in area
Witnesses - Conditions of flight observed
Crash site investigation
Heading on impact
Determine whether any of the following are relevant.
Engine failure: Low flying: Medical: GPS failure: Nav system fail: Flight Inst fail: Flight control fail: Structural fail: Way point error: Fuel: Loss of control: Sabotage
------------------------------------
Bound to be others to emerge.
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With that wealth of experience onboard, would consider only that low because no option. Why not be higher, which would be the obvious place to be with that experience level, prevailing weather, and that well equipped aircraft. Cant get any higher, why? caught in the severe icing conditions that were forecast for the area. Severe icing in any light twin uses up options very rapidly.
Only my opinion based on nothing but what has come out in this thread, and quite a few grey hairs earned flogging light twins for a crust.
Prospector
Only my opinion based on nothing but what has come out in this thread, and quite a few grey hairs earned flogging light twins for a crust.
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prospector
Good one. Didn't consider icing as I was only conscious of the weather as a ground observer and there had been radio contact which presumably was no cause for concern.
Does anyone have a weather for the time with freezing level and cloud coverage other than low stratus ?
Did anyone else fly out of Benalla or Wangaratta on the day ?
Good one. Didn't consider icing as I was only conscious of the weather as a ground observer and there had been radio contact which presumably was no cause for concern.
Does anyone have a weather for the time with freezing level and cloud coverage other than low stratus ?
Did anyone else fly out of Benalla or Wangaratta on the day ?
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Just copied following from a new thread on subject
Benalla Piper Cheyenne crash. Two Melbourne ATCs stood down
SMH
By Robert Wainwright
September 17, 2004
Two Melbourne air traffic controllers have been stood down after preliminary investigations into the death of six people aboard a plane which crashed on a flight from Bankstown to the Victorian town of Benalla two months ago.
The fallout from the tragedy is set to reignite a verbal war over aviation safety as the Federal Government prepares to overhaul the way air space is managed.
Inquiries by the Herald have revealed that Airservices Australia board members discussed the crash a month ago, including detail that the pilot, Kerry Endicott, was not warned on three occasions that he had drifted dangerously off course on the Ulladulla-Benalla leg of the journey.
By the time the plane reached the crash site an hour later, it was 12 kilometres south of the check- point Mr Endicott thought he was heading towards.
He had been flying in cloud cover and rain that made it impossible to realise his error. When he banked left to prepare to land, the Piper Cheyenne crashed into mountainous countryside, killing all on board instantly.
The families of the victims spoke yesterday for the first time since the July 28 tragedy. They are concerned about time it will take authorities to finish their investigations and potential safety problems for others in the meantime.
David Henderson is mourning his brother, businessman Robert Henderson, and niece, Jacqui Stark. They died along with Jacqui's husband, Alan, his friend Geoff Brockie, Belinda Andrews and Mr Endicott.
Mr Henderson said the preliminary report from the Australian Transport Safety Bureau made it clear the plane crashed because it was off course and that Mr Endicott, an experienced pilot, punched the wrong co-ordinates into GPS equipment.
However, they do not know why the plane was allowed to veer almost four degrees from its designated flight path, through controlled air space for hundreds of kilometres between Ulladulla and the Albury border before it disappeared from radar.
They cannot understand why authorities have not told the flying community about the dangers, particular as it will take at least another year before the bureau makes its final report.
Many within the aviation community believe the reason for the silence is concern that the tragedy will be blamed on the controversial air space category known as G-airspace, where authorities say it is too expensive to control air travel.
The public needs some action now, not in 12 months' time when they finish their report," Mr Henderson said yesterday.
"I'm not after blaming someone, but I am concerned that air traffic procedures do not appear to be as robust as we are told. Why else would a highly qualified, professional pilot flying a well-maintained and equipped plane have this type of accident.
"I have asked both the ATSB and Civil Aviation Safety Authority to put out some statement, some warning, but it all seems too hard.
"If there is another accident in the meantime, then I believe they should be held accountable."
Barry and Lex Stark, parents of Alan, who was a Black Hawk helicopter pilot, have been even more frustrated since the accident; ignored by aviation authorities who have not even telephoned their Queensland home to inform them of the impending report.
"I did not appreciate being left out of the loop, particularly when there are so many unanswered questions about why they were so far off track. It seems ridiculous that authorities are sitting there with millions of dollars of equipment, simply noting that an aircraft in bad weather is off track and doing nothing about it.
"People should be made aware of the problems."
Like the other family members, Geoff Brockie's aunt, Joy Fletcher, has visited the crash site and is shocked the pilot could have been so far off course. Mr Brockie had joined what was a joy flight for the afternoon and was due to pilot an international Qantas flight out of Melbourne the same night.
"We haven't been told anything beyond what has been said publicly, and that is not enough to answer our questions. It seems amazing that they could fly so far, through several control zones without a warning. It makes you wonder about other flights."
Airservices Australia remained silent yesterday. It is understood that initial internal inquiries told the board of three occasions before the plane flew into uncontrolled air space that the pilot could have been warned about his flight path.
Mr Henderson has met the Civil Aviation Safety Authority and asked for changes to air space management. But a spokesman for the authority said yesterday its hands were tied until the bureau finished its report.
The Minister for Transport, John Anderson, has announced that Airservices Australia will be stripped of its air space regulatory functions if the Government is re-elected. The power would be transferred to a separate body - the Airspace Directorate.
-----------------------------------
As an ex aircraft accident investigator I can only say we are lapsing in our responsibilities to pass on lessons to our less experienced aviators through this excellent medium.
Let's keep the thread going. That which we raise and discuss may just prevent another terrible event.
Could there have been an icing problem as raised by prospector above and what would have been the likely consequences with a Cheyenne?
Benalla Piper Cheyenne crash. Two Melbourne ATCs stood down
SMH
By Robert Wainwright
September 17, 2004
Two Melbourne air traffic controllers have been stood down after preliminary investigations into the death of six people aboard a plane which crashed on a flight from Bankstown to the Victorian town of Benalla two months ago.
The fallout from the tragedy is set to reignite a verbal war over aviation safety as the Federal Government prepares to overhaul the way air space is managed.
Inquiries by the Herald have revealed that Airservices Australia board members discussed the crash a month ago, including detail that the pilot, Kerry Endicott, was not warned on three occasions that he had drifted dangerously off course on the Ulladulla-Benalla leg of the journey.
By the time the plane reached the crash site an hour later, it was 12 kilometres south of the check- point Mr Endicott thought he was heading towards.
He had been flying in cloud cover and rain that made it impossible to realise his error. When he banked left to prepare to land, the Piper Cheyenne crashed into mountainous countryside, killing all on board instantly.
The families of the victims spoke yesterday for the first time since the July 28 tragedy. They are concerned about time it will take authorities to finish their investigations and potential safety problems for others in the meantime.
David Henderson is mourning his brother, businessman Robert Henderson, and niece, Jacqui Stark. They died along with Jacqui's husband, Alan, his friend Geoff Brockie, Belinda Andrews and Mr Endicott.
Mr Henderson said the preliminary report from the Australian Transport Safety Bureau made it clear the plane crashed because it was off course and that Mr Endicott, an experienced pilot, punched the wrong co-ordinates into GPS equipment.
However, they do not know why the plane was allowed to veer almost four degrees from its designated flight path, through controlled air space for hundreds of kilometres between Ulladulla and the Albury border before it disappeared from radar.
They cannot understand why authorities have not told the flying community about the dangers, particular as it will take at least another year before the bureau makes its final report.
Many within the aviation community believe the reason for the silence is concern that the tragedy will be blamed on the controversial air space category known as G-airspace, where authorities say it is too expensive to control air travel.
The public needs some action now, not in 12 months' time when they finish their report," Mr Henderson said yesterday.
"I'm not after blaming someone, but I am concerned that air traffic procedures do not appear to be as robust as we are told. Why else would a highly qualified, professional pilot flying a well-maintained and equipped plane have this type of accident.
"I have asked both the ATSB and Civil Aviation Safety Authority to put out some statement, some warning, but it all seems too hard.
"If there is another accident in the meantime, then I believe they should be held accountable."
Barry and Lex Stark, parents of Alan, who was a Black Hawk helicopter pilot, have been even more frustrated since the accident; ignored by aviation authorities who have not even telephoned their Queensland home to inform them of the impending report.
"I did not appreciate being left out of the loop, particularly when there are so many unanswered questions about why they were so far off track. It seems ridiculous that authorities are sitting there with millions of dollars of equipment, simply noting that an aircraft in bad weather is off track and doing nothing about it.
"People should be made aware of the problems."
Like the other family members, Geoff Brockie's aunt, Joy Fletcher, has visited the crash site and is shocked the pilot could have been so far off course. Mr Brockie had joined what was a joy flight for the afternoon and was due to pilot an international Qantas flight out of Melbourne the same night.
"We haven't been told anything beyond what has been said publicly, and that is not enough to answer our questions. It seems amazing that they could fly so far, through several control zones without a warning. It makes you wonder about other flights."
Airservices Australia remained silent yesterday. It is understood that initial internal inquiries told the board of three occasions before the plane flew into uncontrolled air space that the pilot could have been warned about his flight path.
Mr Henderson has met the Civil Aviation Safety Authority and asked for changes to air space management. But a spokesman for the authority said yesterday its hands were tied until the bureau finished its report.
The Minister for Transport, John Anderson, has announced that Airservices Australia will be stripped of its air space regulatory functions if the Government is re-elected. The power would be transferred to a separate body - the Airspace Directorate.
-----------------------------------
As an ex aircraft accident investigator I can only say we are lapsing in our responsibilities to pass on lessons to our less experienced aviators through this excellent medium.
Let's keep the thread going. That which we raise and discuss may just prevent another terrible event.
Could there have been an icing problem as raised by prospector above and what would have been the likely consequences with a Cheyenne?