Paul Phelan’s article in The Australian on Fri 10 Aug.
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Paul,
What you argue is in fact the procedural justification and process for the STC, not that the aircraft is in anyway unsafe.
Do you have any evidence to suggest that the increase in the AUW in Australia has contributed to any in-flight failures?
At this time I do not believe there is any proven link.
The timing of your article was at best inappropriate!
What you argue is in fact the procedural justification and process for the STC, not that the aircraft is in anyway unsafe.
Do you have any evidence to suggest that the increase in the AUW in Australia has contributed to any in-flight failures?
At this time I do not believe there is any proven link.
The timing of your article was at best inappropriate!
Paul,
Quite simply, IT IS NOT for you, me or anyone else to decide, speculate or make unqualified assumptions on the cause of this or any other accident.
Whether or not you are qualified, leave it to the ATSB and those responsible for the investigation until you have ALL OF THE FACTS, then you can make your comments and perhaps earn back some of your lost credibility.
Quite simply, IT IS NOT for you, me or anyone else to decide, speculate or make unqualified assumptions on the cause of this or any other accident.
Whether or not you are qualified, leave it to the ATSB and those responsible for the investigation until you have ALL OF THE FACTS, then you can make your comments and perhaps earn back some of your lost credibility.
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I hesitate to enter a dialogue on a forum where I am anonymously accused of dishonesty, opportunism, sensationalism, ignorance of contextual issues, and onanism.
My discussions with the manufacturers’ representatives took place over 25 years ago, so their comments could not be expected to cover issues that had not become evident at that time.
The manufacturer’s representatives expressed surprise at the certification to higher weights, and asked if somebody had fitted “a couple of turbo 350s” for the flight test.
No, there is no evidence that the aircraft would not have broken up if they had been operated at a lighter weight. In fact some of the (about) 30 Shrikes which have now suffered structural failures had probably not been exposed to higher operating weights. Clearly however, higher operating weights increase the risk of a failure incurring . That is one of the two reasons why MTOWs are imposed.
As to whether the type is safe or not, a quote from Mr Swift’s treatise seems relevant. “Things are not always what they seem. Despite the robust appearance, at last count 24 Aero Commanders had lost wings in flight, 35 spars had been found cracked on the ground, and hundreds of other spars had defects caused by fatigue, corrosion, stress corrosion and static overload.” Obviously frustrated by inaction on the issue, Mr Swift exclaimed: “How was it that such fundamental structural problems were still unresolved after forty years?”
That was written in 1995. I do not understand why anybody who is interested in this issue doesn’t keep a copy of Mr Swift’s study in their office.
I have not identified a single pilot who believes that an unmodified factory standard Shrike was ever able to demonstrate a 1% engine-out climb under the certification conditions at any weight in excess of 6,750 lb. I once tried it at 6,750 and the outcome was fully consistent with the results reported by the GAF chief test pilot.
Pilots who are much more familiar with the type than I am assure me that the average airframe hours on the Shrike fleet are in the order of 25,000. This would be partly explained by their use on coastwatch and night freight operations.
As for “appropriateness”, this is a live issue which has been ignored by responsible people for a long time.
I don't plan to continue debate on this forum. If anybody wants to communicate on relevant issues my e-mail is [email protected]
(Edited only to include para breaks. T.W.)
My discussions with the manufacturers’ representatives took place over 25 years ago, so their comments could not be expected to cover issues that had not become evident at that time.
The manufacturer’s representatives expressed surprise at the certification to higher weights, and asked if somebody had fitted “a couple of turbo 350s” for the flight test.
No, there is no evidence that the aircraft would not have broken up if they had been operated at a lighter weight. In fact some of the (about) 30 Shrikes which have now suffered structural failures had probably not been exposed to higher operating weights. Clearly however, higher operating weights increase the risk of a failure incurring . That is one of the two reasons why MTOWs are imposed.
As to whether the type is safe or not, a quote from Mr Swift’s treatise seems relevant. “Things are not always what they seem. Despite the robust appearance, at last count 24 Aero Commanders had lost wings in flight, 35 spars had been found cracked on the ground, and hundreds of other spars had defects caused by fatigue, corrosion, stress corrosion and static overload.” Obviously frustrated by inaction on the issue, Mr Swift exclaimed: “How was it that such fundamental structural problems were still unresolved after forty years?”
That was written in 1995. I do not understand why anybody who is interested in this issue doesn’t keep a copy of Mr Swift’s study in their office.
I have not identified a single pilot who believes that an unmodified factory standard Shrike was ever able to demonstrate a 1% engine-out climb under the certification conditions at any weight in excess of 6,750 lb. I once tried it at 6,750 and the outcome was fully consistent with the results reported by the GAF chief test pilot.
Pilots who are much more familiar with the type than I am assure me that the average airframe hours on the Shrike fleet are in the order of 25,000. This would be partly explained by their use on coastwatch and night freight operations.
As for “appropriateness”, this is a live issue which has been ignored by responsible people for a long time.
I don't plan to continue debate on this forum. If anybody wants to communicate on relevant issues my e-mail is [email protected]
(Edited only to include para breaks. T.W.)
Last edited by Paul Phelan; 16th Aug 2007 at 01:04. Reason: I omitted a paragraph
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Paul's research has raised some interesting questions though...
Operationally speaking it is a good thing that the type has not had a spate of engine failures in IMC. I wonder how many pilots flying the machine IFR actually recalculate their approach minima's to a height that would guarantee obstacle clearance based on what can only be argued as increadibly poor single engine climb performance? The figures suggested for the type fall way short of the 100' clearance @ 2.5% which the charts are based on...
Operationally speaking it is a good thing that the type has not had a spate of engine failures in IMC. I wonder how many pilots flying the machine IFR actually recalculate their approach minima's to a height that would guarantee obstacle clearance based on what can only be argued as increadibly poor single engine climb performance? The figures suggested for the type fall way short of the 100' clearance @ 2.5% which the charts are based on...
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Most people who regularly read newspapers understand that it’s not journalists, but subeditors, who write the headlines.
Whether it's you or subeditors who write the headlines, this particular one is a disgrace. It reflects badly on you and your paper.
I believe your paper should issue an unreserved apology to the grieving families and friends of those who perished in both accidents. It's the right thing to do - and probably wise!
Di
Paul,
First up, thanks for having the cohonas to defend yourself publically- not many journalists do.
Why, then, was this the clear implication of your acticle?
But there is no evidense that this was the reason or even a factor in these accidents. The original MTOW was imposed for the OTHER of the two reasons, performance. Indeed you note that there have been quite a number of in-flight break-ups of aircraft opperated to the original MTOW.
As the headline of the article is clearly misleading, and your name is on the by-line, have you asked the newspaper to print a retraction?
First up, thanks for having the cohonas to defend yourself publically- not many journalists do.
No, there is no evidence that the aircraft would not have broken up if they had been operated at a lighter weight.
Clearly however, higher operating weights increase the risk of a failure incurring . That is one of the two reasons why MTOWs are imposed.
As the headline of the article is clearly misleading, and your name is on the by-line, have you asked the newspaper to print a retraction?
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Further................
There are clearly two issues in this discussion:
(1) the increased Australian TOW, and
(2) the known problems with the wing.
The known spar issues have no proven association whatsoever to do with the increased TOW applied in the Australian STC.
Some investigation, would to me, indicate that the known problems with the spar relate to the "inner" wing - ie: inboard of the engines. Both of the failures in Australia were, I understand, in the outer wing.
I agree with the previous two posts, an apology in the Australian would be the right thing to do. And the sub-editor should butt out of what he obviously knows nothing about.
Crap – Look harder! I recall a number of the Exec pilots acted as observers on test flights back in the early 70's and the Shrike at 7150lb made the required climb at 5000ft. There were others around at the time that would verify that also. The VFR requirement I recall was to maintain height at 7400lb - it did that also.
Paul, it is good to see you here, however get your facts right, publish at an appropriate time with due consideration for factors at the time and perhaps this dialogue would not occur.
Your call. And I say again, it is good to see you post here. But just like our mate Dick has found, to ignore this type of discussion only makes it worse - for yourself as a industry advocate and the credibility of both you the journals you write for. You should be well aware after many years writing about aviation matters that when you fail to get it right, you can always expect some flak!
In this case it is well deserved!
(1) the increased Australian TOW, and
(2) the known problems with the wing.
The known spar issues have no proven association whatsoever to do with the increased TOW applied in the Australian STC.
Some investigation, would to me, indicate that the known problems with the spar relate to the "inner" wing - ie: inboard of the engines. Both of the failures in Australia were, I understand, in the outer wing.
I agree with the previous two posts, an apology in the Australian would be the right thing to do. And the sub-editor should butt out of what he obviously knows nothing about.
I have not identified a single pilot who believes that an unmodified factory standard Shrike was ever able to demonstrate a 1% engine-out climb under the certification conditions at any weight in excess of 6,750 lb.
I hesitate to enter a dialogue on a forum where I am anonymously accused of dishonesty, opportunism, sensationalism, ignorance of contextual issues, and onanism.
I don't plan to continue debate on this forum.
In this case it is well deserved!
Without wishing to comment on the actual case, whose details I do not know, nor do I know the slightest thing about Shrikes.
But with my engineers hat on, I have to say this is not the truth, the whole truth and only the truth because such a relationship certainly exists in theory.
The fatigue life of a chunk of Aluminium alloy is a function of its entire stress history from new. That is the integral of load applied times length of time applied.
In addition, as loads increase, so does sensitivity to stress corrosion and cracking at stress raisers caused by allowable manufacturing defects.
The "Hard Time" limits prescribed for the replacement of certain parts after a certain number of hours or cycles is predicated on the expected loading of that part. Change the loading conditions and the part may last a lot shorter time before failure.
This is an inexact science, as the continual stream of SB's and AD's even for Boeing's finest attests.
IF (and its a big if) structural failure was a factor in this terrible accident, then it will not be the first time that a well maintained and professionally flown aircraft has fallen victim to the aircrafts previous history.
The known spar issues have no proven association whatsoever to do with the increased TOW applied in the Australian STC.
The fatigue life of a chunk of Aluminium alloy is a function of its entire stress history from new. That is the integral of load applied times length of time applied.
In addition, as loads increase, so does sensitivity to stress corrosion and cracking at stress raisers caused by allowable manufacturing defects.
The "Hard Time" limits prescribed for the replacement of certain parts after a certain number of hours or cycles is predicated on the expected loading of that part. Change the loading conditions and the part may last a lot shorter time before failure.
This is an inexact science, as the continual stream of SB's and AD's even for Boeing's finest attests.
IF (and its a big if) structural failure was a factor in this terrible accident, then it will not be the first time that a well maintained and professionally flown aircraft has fallen victim to the aircrafts previous history.
Moderator
There are a few suggestions in this thread which are a bit wide of the mark.
I note that I missed Paul's original article so I offer no comments specifically directed towards it.
The Commanders have a known set of problems which the TC holder and regulators set out to address via SBs, ADs, etc ... just like every other Type
Some general thoughts from the depths of the memory cells only -
(a) the then FAA requirement (if you wish you can review it on the FAA website's historical rules) for OEI climb differed to what the ANO required. The relevant Australian operator sought to utilise that difference to gain some extra weight and that sort of thing has been done for various aircraft over the years. My recollection is that the justification was based on structural detail comparison with larger models within the range with any non-conservative differences being addressed by mod - eg, the 500A, with which I had some involvement, had to have uprated wheels/brakes as best I recall. Models involved had to demonstrate the climb capability to justify certification aspects of the proposed weight delta.
(b) generalised references to aircraft being overweight are "correct" only to the extent that the Australian permissible MTOW exceeded the US figure. However, it must be understood that such "excess" weight was perfectly legitimate and authorised by the Australian AFM. It is very important to keep in mind that the then rules permitted local recertifications. Many were done and all required the appropriate level of tap-dancing ... DCA et seq certification folk were never amenable to being hoodwinked. When we are talking about the period and performance we are looking at eminently fine chaps such as Tenenbaum, Fincher, et al. All highly principled (sometimes to the point of being a pain in the neck). That doesn't suggest that mistakes were never made .. but the attitude and general attention to detail was always there. To suggest that the Oz regulator engineering folk were other than first rate is not supported by history regardless of what popular perception may be or have been.
(c) He was also very much aware of the fatigue issues ... Notty and I have discussed various structure cracks over the years .. he was very aware of such problems and always appeared conservative in his attitude. However, as Steve indicates in his paper, the very nature of inspection aspects of fatigue is tied up with inspectability ... ie it's a bit of a mongrel beast ..
(d) There has never been to my knowledge any meaningful flight testing done at the higher (VFR) takeoff weight 3357kg or at the higher IFR wt of 3243kg .. It would be useful for the writer to check his facts with CASA airworthiness. The basis for the Oz weights were the climb tests.
(e) the coastwatch contract .. came much later. If I recall correctly, the earlier Shrikes were used for the Navy target towing contract ? I recall a colleague relating a tale wherein the towing to simulated attack run evolution got a bit out of synch with the target retrieval ... something about the target filling up with water ...
(f) Also this category of aircraft is only required to maintain 5000' on one engine at ISA conditions. Not indicative of the aussie environment. .. misses the point. The certification requirement only puts a line in the sand. It is up to the operator's policy as to whether any further conservatism ought to be incorporated into routine operations.
(g) In June 1991, seventeen senior engineers met in Seattle . The linked paper is well worth a read for general education. Be assured that Steve Swift and Alan Emmerson, both with the Regulator and fine chaps, were very soundly versed in structural fatigue matters.
(h) The Department of Aviation never made available any flight test data or structural analysis to support the higher STC weights. .. but the data exists .. it was used to broker the subsequent 500A work. One needs to keep in mind that the Regulator has always taken the proprietary rights interests of certification data pretty seriously.
(i) The weights were challenged in 1982 when the Government Aircraft Factory’s chief test pilot . I don't recall this episode nor have I seen any related data. However, one needs to be careful that one matches the appropriate standards against the performance ? 101.22 went through several revisions (as I recall to suit some problems with which the Nomad presented). The 500S work was done to the earlier (and simpler) requirements. It is not at all inconceivable that the stated GAF tests were done to one of the later revisions ? (Note - I am not anti-Nomad, in fact quite the opposite, having worked on the beast during two separate periods).
(j) The higher weights were unilaterally taken by Australia only. ... as was quite right and proper under the regs of the time. It is only since the later regs came in that the local regulator has been tied to the NAA requirements.
(k) Probably worth noting is the fact that if the power available is just sufficient to meet the minimum performance standards with a TOW max of 6,750 lb, the additional power required to meet the same performance standard at a TOW max of 7,150 lb (Australian Certification) is 14.8% .. sounds like arrant nonsense to me. The two certification requirements were quite different.
(l) It is a serious enough deviation from the manufacturer’s limits for you to insist on a performance audit, even if it means by-passing the D.O.A. officers and going direct to the Minister. Having worked over the years with these officers may I assure readers that they were never pushovers when it came to demonstrating certification compliance. On the contrary, there are numerous instances of FOT certifications where the local regulator required additional performance tests .. the Rockwell Commander singles come to mind as an instance ..
(m) The manufacturer’s representatives expressed surprise at the certification to higher weights, and asked if somebody had fitted “a couple of turbo 350s” for the flight test. Only speculation but this comment only makes sense in terms of considering a recertification to the original requirement, not a different one ...
(n) I have not identified a single pilot who believes that an unmodified factory standard Shrike was ever able to demonstrate a 1% engine-out climb under the certification conditions at any weight in excess of 6,750 lb. .. apologies but I have so flown. The secret, of course, is that one has to define WHICH certification standard is subject to test ... certainly, the higher Oz weights could be flown to the then Oz requirement.
(o) [i]I wonder how many pilots flying the machine IFR actually recalculate their approach minima's to a height that would guarantee obstacle clearance based on what can only be argued as increadibly poor single engine climb performance?[/i] ... you mean like most other light twins of similar certification basis ?
(p) single engine climb exercise, please divulge how exactly you set zero thrust ... not relevant .. OEI tests are done shutdown and feathered.
I note that I missed Paul's original article so I offer no comments specifically directed towards it.
The Commanders have a known set of problems which the TC holder and regulators set out to address via SBs, ADs, etc ... just like every other Type
Some general thoughts from the depths of the memory cells only -
(a) the then FAA requirement (if you wish you can review it on the FAA website's historical rules) for OEI climb differed to what the ANO required. The relevant Australian operator sought to utilise that difference to gain some extra weight and that sort of thing has been done for various aircraft over the years. My recollection is that the justification was based on structural detail comparison with larger models within the range with any non-conservative differences being addressed by mod - eg, the 500A, with which I had some involvement, had to have uprated wheels/brakes as best I recall. Models involved had to demonstrate the climb capability to justify certification aspects of the proposed weight delta.
(b) generalised references to aircraft being overweight are "correct" only to the extent that the Australian permissible MTOW exceeded the US figure. However, it must be understood that such "excess" weight was perfectly legitimate and authorised by the Australian AFM. It is very important to keep in mind that the then rules permitted local recertifications. Many were done and all required the appropriate level of tap-dancing ... DCA et seq certification folk were never amenable to being hoodwinked. When we are talking about the period and performance we are looking at eminently fine chaps such as Tenenbaum, Fincher, et al. All highly principled (sometimes to the point of being a pain in the neck). That doesn't suggest that mistakes were never made .. but the attitude and general attention to detail was always there. To suggest that the Oz regulator engineering folk were other than first rate is not supported by history regardless of what popular perception may be or have been.
(c) He was also very much aware of the fatigue issues ... Notty and I have discussed various structure cracks over the years .. he was very aware of such problems and always appeared conservative in his attitude. However, as Steve indicates in his paper, the very nature of inspection aspects of fatigue is tied up with inspectability ... ie it's a bit of a mongrel beast ..
(d) There has never been to my knowledge any meaningful flight testing done at the higher (VFR) takeoff weight 3357kg or at the higher IFR wt of 3243kg .. It would be useful for the writer to check his facts with CASA airworthiness. The basis for the Oz weights were the climb tests.
(e) the coastwatch contract .. came much later. If I recall correctly, the earlier Shrikes were used for the Navy target towing contract ? I recall a colleague relating a tale wherein the towing to simulated attack run evolution got a bit out of synch with the target retrieval ... something about the target filling up with water ...
(f) Also this category of aircraft is only required to maintain 5000' on one engine at ISA conditions. Not indicative of the aussie environment. .. misses the point. The certification requirement only puts a line in the sand. It is up to the operator's policy as to whether any further conservatism ought to be incorporated into routine operations.
(g) In June 1991, seventeen senior engineers met in Seattle . The linked paper is well worth a read for general education. Be assured that Steve Swift and Alan Emmerson, both with the Regulator and fine chaps, were very soundly versed in structural fatigue matters.
(h) The Department of Aviation never made available any flight test data or structural analysis to support the higher STC weights. .. but the data exists .. it was used to broker the subsequent 500A work. One needs to keep in mind that the Regulator has always taken the proprietary rights interests of certification data pretty seriously.
(i) The weights were challenged in 1982 when the Government Aircraft Factory’s chief test pilot . I don't recall this episode nor have I seen any related data. However, one needs to be careful that one matches the appropriate standards against the performance ? 101.22 went through several revisions (as I recall to suit some problems with which the Nomad presented). The 500S work was done to the earlier (and simpler) requirements. It is not at all inconceivable that the stated GAF tests were done to one of the later revisions ? (Note - I am not anti-Nomad, in fact quite the opposite, having worked on the beast during two separate periods).
(j) The higher weights were unilaterally taken by Australia only. ... as was quite right and proper under the regs of the time. It is only since the later regs came in that the local regulator has been tied to the NAA requirements.
(k) Probably worth noting is the fact that if the power available is just sufficient to meet the minimum performance standards with a TOW max of 6,750 lb, the additional power required to meet the same performance standard at a TOW max of 7,150 lb (Australian Certification) is 14.8% .. sounds like arrant nonsense to me. The two certification requirements were quite different.
(l) It is a serious enough deviation from the manufacturer’s limits for you to insist on a performance audit, even if it means by-passing the D.O.A. officers and going direct to the Minister. Having worked over the years with these officers may I assure readers that they were never pushovers when it came to demonstrating certification compliance. On the contrary, there are numerous instances of FOT certifications where the local regulator required additional performance tests .. the Rockwell Commander singles come to mind as an instance ..
(m) The manufacturer’s representatives expressed surprise at the certification to higher weights, and asked if somebody had fitted “a couple of turbo 350s” for the flight test. Only speculation but this comment only makes sense in terms of considering a recertification to the original requirement, not a different one ...
(n) I have not identified a single pilot who believes that an unmodified factory standard Shrike was ever able to demonstrate a 1% engine-out climb under the certification conditions at any weight in excess of 6,750 lb. .. apologies but I have so flown. The secret, of course, is that one has to define WHICH certification standard is subject to test ... certainly, the higher Oz weights could be flown to the then Oz requirement.
(o) [i]I wonder how many pilots flying the machine IFR actually recalculate their approach minima's to a height that would guarantee obstacle clearance based on what can only be argued as increadibly poor single engine climb performance?[/i] ... you mean like most other light twins of similar certification basis ?
(p) single engine climb exercise, please divulge how exactly you set zero thrust ... not relevant .. OEI tests are done shutdown and feathered.
Folks,
To add a little fuel to the fire!
Are the increased gross weight any longer valid, an STC to an airworthiness standard that has been repealed, and an Australian AFM that is no longer valid.
This came up when C-47, VH-EDC went swimming in Botany Bay some years ago. The pilot was accused of operating over MTOW, base on the old Australian AFM weights, (26,200lb, as I recall, the end result of an industrial dispute) but the pilot was entitled to operate the aircraft to the FAA AFM, which specified (in this case) a higher weight.
My best guess is that the T-C AFM limitations now apply to Aero Commanders--- comments --- unless CASA has produced a concession to continue operations at the "Australian" weights.
There must have been some structural justification of the higher weight, as I recall a spar strap was required, and the existing Australian spar strap was an acceptable means of compliance when an FAA AD for a spar strap appeared on the scene.
Tootle pip!
To add a little fuel to the fire!
Are the increased gross weight any longer valid, an STC to an airworthiness standard that has been repealed, and an Australian AFM that is no longer valid.
This came up when C-47, VH-EDC went swimming in Botany Bay some years ago. The pilot was accused of operating over MTOW, base on the old Australian AFM weights, (26,200lb, as I recall, the end result of an industrial dispute) but the pilot was entitled to operate the aircraft to the FAA AFM, which specified (in this case) a higher weight.
My best guess is that the T-C AFM limitations now apply to Aero Commanders--- comments --- unless CASA has produced a concession to continue operations at the "Australian" weights.
There must have been some structural justification of the higher weight, as I recall a spar strap was required, and the existing Australian spar strap was an acceptable means of compliance when an FAA AD for a spar strap appeared on the scene.
Tootle pip!
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Originally Posted by john_tullamarine
I note that I missed Paul's original article so I offer no comments specifically directed towards it.
John, excellent post. For your information, Paul Phelan's article is still available online (in The Australian).
Moderator
Following article courtesy of The Australian:
Crashed Shrikes were overweight
Paul Phelan | August 10, 2007
GOVERNMENT officials were warned 25 years ago that Shrike Commander aircraft like the one that crashed near Melbourne on July 31 were allowed to fly at weights 10 per cent higher than they were designed for.
At least 25 Aero Commanders worldwide have disintegrated in flight, another having crashed fatally in Tasmania in February 2004 when a wing separated.
Flying at heavier weights increases the risk of structural failure, and the deadly mix of turbulence and latent fatigue can trigger in-flight break-up.
In the US, their country of origin, Shrikes are limited to a 3062kg maximum takeoff weight, but when they were imported here as used aircraft, the (then) Department of Aviation issued a "supplemental type certificate" allowing them to fly at up to 3357kg, the equivalent of three extra passengers.
Though CASA insists that test flights were carried out to prove the aircraft's capabilities, performance engineers from Gulfstream American Corporation, its manufacturer told Australian operators the assessment must be wrong.
"If we thought it would fly 10 per cent heavier, we'd have certified it at that weight, sold a lot more planes, and made a lot more money," said a Gulfstream engineer. The decision created such dismay at the Government Aircraft Factory, which was building competing aircraft, that its management hired a Shrike Commander and its chief test pilot flew a series of test flights to evaluate its engine-out performance against certification requirements.
Though aircraft in this category must show they can maintain a 1 per cent climb gradient with one engine shut down, tests showed it didn't quite meet the requirement even at the US-certified weight, and it couldn't even maintain height on one engine at the higher weights approved in Australia.
Consulting aeronautical engineer Malcolm McLeary supported calls for a review, saying there appeared to be three good reasons why it was warranted: "The manufacturer has not designed or the state authority of origin has not approved the operation to the higher all up weight figures. The higher weights were unilaterally taken by Australia only. The flight tests of an Aero Commander carried out by GAF show non-compliance to the certification standards. And the power loading for the type (weight per available horsepower) is suspiciously high when compared with other aircraft supposedly designed to meet the same requirements."
Mr McLeary said that to carry the extra weight safely, the Shrike would have needed at least 15 per cent more horsepower than it had. He also scoffed at the DoA's suggestion that the GAF test aircraft's performance was due to age: "This would indicate that the flight test aircraft had in fact degraded by over 20 per cent, which is unlikely."
The Gulfstream engineer agreed that the performance of an aircraft that had flown only a little over 3000 hours could be degraded by 20 per cent: "Well, maybe if it was run over by a bulldozer," he quipped.
CASA engineer C. S. Swift, when he published a detailed study of the Shrike's woes, exclaimed: "How was it that such fundamental structural problems were still unresolved after 40 years?"
But 12 years later, about 50 Shrike Commanders are still flying in Australia. More than half are registered to General Aviation Maintenance Pty Ltd, the operators of the crashed plane, and they are still certified to fly here at a 10 per cent heavier MTOW than the US regulator allows.
The Shrike remains popular with commercial operators because of the weight concession, but its pilots are now worried that the average aircraft in Australia has flown about 25,000 hours at unusually heavy weights.
Without commenting on the veracity of the article it is worthy to note the article states:
That statement appears to be confirmed by this CASA pdf document and does not attribute the recent Shrike accident in Victoria to the Australian DCA/CASA approved higher gross weight for the Shrike.
Tail Wheel
Crashed Shrikes were overweight
Paul Phelan | August 10, 2007
GOVERNMENT officials were warned 25 years ago that Shrike Commander aircraft like the one that crashed near Melbourne on July 31 were allowed to fly at weights 10 per cent higher than they were designed for.
At least 25 Aero Commanders worldwide have disintegrated in flight, another having crashed fatally in Tasmania in February 2004 when a wing separated.
Flying at heavier weights increases the risk of structural failure, and the deadly mix of turbulence and latent fatigue can trigger in-flight break-up.
In the US, their country of origin, Shrikes are limited to a 3062kg maximum takeoff weight, but when they were imported here as used aircraft, the (then) Department of Aviation issued a "supplemental type certificate" allowing them to fly at up to 3357kg, the equivalent of three extra passengers.
Though CASA insists that test flights were carried out to prove the aircraft's capabilities, performance engineers from Gulfstream American Corporation, its manufacturer told Australian operators the assessment must be wrong.
"If we thought it would fly 10 per cent heavier, we'd have certified it at that weight, sold a lot more planes, and made a lot more money," said a Gulfstream engineer. The decision created such dismay at the Government Aircraft Factory, which was building competing aircraft, that its management hired a Shrike Commander and its chief test pilot flew a series of test flights to evaluate its engine-out performance against certification requirements.
Though aircraft in this category must show they can maintain a 1 per cent climb gradient with one engine shut down, tests showed it didn't quite meet the requirement even at the US-certified weight, and it couldn't even maintain height on one engine at the higher weights approved in Australia.
Consulting aeronautical engineer Malcolm McLeary supported calls for a review, saying there appeared to be three good reasons why it was warranted: "The manufacturer has not designed or the state authority of origin has not approved the operation to the higher all up weight figures. The higher weights were unilaterally taken by Australia only. The flight tests of an Aero Commander carried out by GAF show non-compliance to the certification standards. And the power loading for the type (weight per available horsepower) is suspiciously high when compared with other aircraft supposedly designed to meet the same requirements."
Mr McLeary said that to carry the extra weight safely, the Shrike would have needed at least 15 per cent more horsepower than it had. He also scoffed at the DoA's suggestion that the GAF test aircraft's performance was due to age: "This would indicate that the flight test aircraft had in fact degraded by over 20 per cent, which is unlikely."
The Gulfstream engineer agreed that the performance of an aircraft that had flown only a little over 3000 hours could be degraded by 20 per cent: "Well, maybe if it was run over by a bulldozer," he quipped.
CASA engineer C. S. Swift, when he published a detailed study of the Shrike's woes, exclaimed: "How was it that such fundamental structural problems were still unresolved after 40 years?"
But 12 years later, about 50 Shrike Commanders are still flying in Australia. More than half are registered to General Aviation Maintenance Pty Ltd, the operators of the crashed plane, and they are still certified to fly here at a 10 per cent heavier MTOW than the US regulator allows.
The Shrike remains popular with commercial operators because of the weight concession, but its pilots are now worried that the average aircraft in Australia has flown about 25,000 hours at unusually heavy weights.
---------------------------------------
Without commenting on the veracity of the article it is worthy to note the article states:
GOVERNMENT officials were warned 25 years ago that Shrike Commander aircraft like the one that crashed near Melbourne on July 31 were allowed to fly at weights 10 per cent higher than they were designed for. (my bold Italics).
Tail Wheel
If the Shrike really was designed to run at the ragged edge of fatigue strength design factors such that a 10% MTOW increase would push it over the edge, then surely it would have been fitted with some kind of fatigue index device, a la Bulldogs etc?
A
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Parallels may end riddle
Article from: The Sunday Tasmanian
MICHAEL STEDMAN
August 19, 2007 12:00am
THE Civil Aviation Safety Authority has confirmed it is looking into alarming similarities between a plane crash that killed two in Victoria last month and an accident near Hobart in 2004.
Millionaire aviation businessman Steve Nott and young pilot Janelle Johnston died when their twin-engined Aero Commander 500 went down near Clonbinane in Victoria on July 31.
Striking similarities have emerged with the death of 21-year-old-pilot Heather Cochrane who was the sole occupant of an identical plane that crashed in fine weather on the way from Hobart to Devonport in 2004.
The Australian Transport Safety Bureau, which is investigating the crash, has noted "intriguing parallels" between the two accidents.
It is hoped the new investigation may provide answers about what caused the 2004 tragedy -- the exact cause of which remains a mystery.
Wreckage was scattered over 1300m in the 2004 crash "consistent with the aircraft having sustained an in-flight structural failure of both wings and the tailplane," the ATSB report said.
Early accounts of the Victorian accident are that the plane sustained massive damage in mid-air -- with both wings and its tail torn off.
The tail section was found 700m from the fuselage.
CASA spokesman Peter Gibson said it had contacted the operators of 65 registered Aero Commanders around the country to see if they had had problems with their planes.
Five Aero Commanders are registered in Tasmania.
But Mr Gibson said, at this stage, there was no need to ground the fleet -- most of which were more than 30 years old. "We are aware of the similarities (between the accidents) but we need evidence of a real problem and at this stage we don't have that," Mr Gibson said.
Operators too are not worried about the safety of the planes, which are often described as the "workhorses of the sky".
Tasmanian Aero Club manager Joe Miller said he and his pilots had no concerns about flying their Aero Commanders, which is the sister aircraft to the one that went down in 2004.
"They are built like a brick ****house and we have not had any problems with wing fatigue or structural problems since we started operating them here," he said.
But Aero Commanders have had a long history of in-flight accidents.
A paper prepared by CASA principal fatigue engineer S. Swift in 1995 highlighted 24 cases where Aero Commanders had lost wings in flight, and 35 others where serious cracks had been found.
CASA said problems with wing fatigue and cracking had been addressed in ageing aircraft maintenance directives and through ongoing inspections.
ATSB deputy director aviation safety and investigation Julian Walsh said early evidence from the Victorian crash was that the maintenance regime had been adhered to.
He said investigators were looking for anything that linked the latest crash with the Tasmanian accident.
"There is no doubt there are some intriguing parallels between the two and, as the investigation develops, that will be something we will be particularly interested in," Mr Walsh said.
He said the weather on the night of the accident, which included severe wind gusts of up to 80km/h, was of "significant interest".
They will also look closely at the auto-pilot, which was identified as a possible factor in the Tasmanian crash.
Tasmanian independent aviation consultant Brian Morgan, who investigated the 2004 accident for charter operator Tasair, said two similar accidents were not proof of an inherent problem.
"Aero Commanders are one of my favourite aeroplanes to fly -- they are wonderful aeroplanes, very stable and very easy to fly," Mr Morgan said.
"Both aircraft appear to have suffered structural failures in the air but, whether that is due to inherent problems of the aircraft or entirely different circumstances, we may never know."
A preliminary report into the Victorian accident is likely to be released by the end of the month.
THIS is a bit more of a professional effort from a journalist!
Di
Article from: The Sunday Tasmanian
MICHAEL STEDMAN
August 19, 2007 12:00am
THE Civil Aviation Safety Authority has confirmed it is looking into alarming similarities between a plane crash that killed two in Victoria last month and an accident near Hobart in 2004.
Millionaire aviation businessman Steve Nott and young pilot Janelle Johnston died when their twin-engined Aero Commander 500 went down near Clonbinane in Victoria on July 31.
Striking similarities have emerged with the death of 21-year-old-pilot Heather Cochrane who was the sole occupant of an identical plane that crashed in fine weather on the way from Hobart to Devonport in 2004.
The Australian Transport Safety Bureau, which is investigating the crash, has noted "intriguing parallels" between the two accidents.
It is hoped the new investigation may provide answers about what caused the 2004 tragedy -- the exact cause of which remains a mystery.
Wreckage was scattered over 1300m in the 2004 crash "consistent with the aircraft having sustained an in-flight structural failure of both wings and the tailplane," the ATSB report said.
Early accounts of the Victorian accident are that the plane sustained massive damage in mid-air -- with both wings and its tail torn off.
The tail section was found 700m from the fuselage.
CASA spokesman Peter Gibson said it had contacted the operators of 65 registered Aero Commanders around the country to see if they had had problems with their planes.
Five Aero Commanders are registered in Tasmania.
But Mr Gibson said, at this stage, there was no need to ground the fleet -- most of which were more than 30 years old. "We are aware of the similarities (between the accidents) but we need evidence of a real problem and at this stage we don't have that," Mr Gibson said.
Operators too are not worried about the safety of the planes, which are often described as the "workhorses of the sky".
Tasmanian Aero Club manager Joe Miller said he and his pilots had no concerns about flying their Aero Commanders, which is the sister aircraft to the one that went down in 2004.
"They are built like a brick ****house and we have not had any problems with wing fatigue or structural problems since we started operating them here," he said.
But Aero Commanders have had a long history of in-flight accidents.
A paper prepared by CASA principal fatigue engineer S. Swift in 1995 highlighted 24 cases where Aero Commanders had lost wings in flight, and 35 others where serious cracks had been found.
CASA said problems with wing fatigue and cracking had been addressed in ageing aircraft maintenance directives and through ongoing inspections.
ATSB deputy director aviation safety and investigation Julian Walsh said early evidence from the Victorian crash was that the maintenance regime had been adhered to.
He said investigators were looking for anything that linked the latest crash with the Tasmanian accident.
"There is no doubt there are some intriguing parallels between the two and, as the investigation develops, that will be something we will be particularly interested in," Mr Walsh said.
He said the weather on the night of the accident, which included severe wind gusts of up to 80km/h, was of "significant interest".
They will also look closely at the auto-pilot, which was identified as a possible factor in the Tasmanian crash.
Tasmanian independent aviation consultant Brian Morgan, who investigated the 2004 accident for charter operator Tasair, said two similar accidents were not proof of an inherent problem.
"Aero Commanders are one of my favourite aeroplanes to fly -- they are wonderful aeroplanes, very stable and very easy to fly," Mr Morgan said.
"Both aircraft appear to have suffered structural failures in the air but, whether that is due to inherent problems of the aircraft or entirely different circumstances, we may never know."
A preliminary report into the Victorian accident is likely to be released by the end of the month.
THIS is a bit more of a professional effort from a journalist!
Di
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We need Paul
Would there have been further investigations into these two accidents if Paul had not written his article?
Those who say "leave it to ATSB" or "Leave these things to CASA" should read the Coroner's report on the Lockhart River crash. In a report that many say is "too forgiving" the Coroner criticises the aparent agressive disagreements between ATSB and CASA.
Thank god they are both watching each other. This is much better than it was when they were all the one happy family and no-one was watching. Pilots and operators were not game to criticise, as they all had renewals coming up, or approvals, dispensations etc to get or renew.
But it appears that this may be affecting the integrity of their reports now, and the Coroner discounted some of their findings. We cannot just say "leave it to the ATSB" although their reports usually contain valuable information.
It appears that Australia's Shrikes did have approval to fly in Australia at weights much greater than the maker or the FAA approved, and many (if not all) probably did it many times.
I wonder why this approval was given "only in Australia".
Those who say "leave it to ATSB" or "Leave these things to CASA" should read the Coroner's report on the Lockhart River crash. In a report that many say is "too forgiving" the Coroner criticises the aparent agressive disagreements between ATSB and CASA.
Thank god they are both watching each other. This is much better than it was when they were all the one happy family and no-one was watching. Pilots and operators were not game to criticise, as they all had renewals coming up, or approvals, dispensations etc to get or renew.
But it appears that this may be affecting the integrity of their reports now, and the Coroner discounted some of their findings. We cannot just say "leave it to the ATSB" although their reports usually contain valuable information.
It appears that Australia's Shrikes did have approval to fly in Australia at weights much greater than the maker or the FAA approved, and many (if not all) probably did it many times.
I wonder why this approval was given "only in Australia".
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Old Aeroplanes.
CASA spokesman Peter Gibson said it had contacted the operators of 65 registered Aero Commanders around the country to see if they had had problems with their planes.
Five Aero Commanders are registered in Tasmania.
But Mr Gibson said, at this stage, there was no need to ground the fleet -- most of which were more than 30 years old. "We are aware of the similarities (between the accidents) but we need evidence of a real problem and at this stage we don't have that," Mr Gibson said.
Operators too are not worried about the safety of the planes, which are often described as the "workhorses of the sky".
Tasmanian Aero Club manager Joe Miller said he and his pilots had no concerns about flying their Aero Commanders, which is the sister aircraft to the one that went down in 2004.
So what sort of response did Peter Gibson expect from the operators?
Tasmanian Aero Club manager Joe Miller said he and his pilots had no concerns about flying their Aero Commanders, which is the sister aircraft to the one that went down in 2004.
"They are built like a brick ****house and we have not had any problems with wing fatigue or structural problems since we started operating them here," he said.
So succinctly put, a true GA manager.
Was the increase in MTOW requested to obtain an advantage in order to obtain a contract? The fact is that a number of these aircraft have broken up mid flight should question the wisdom of such an approval.
In the US, their country of origin, Shrikes are limited to a 3062kg maximum takeoff weight, but when they were imported here as used aircraft, the (then) Department of Aviation issued a "supplemental type certificate" allowing them to fly at up to 3357kg, the equivalent of three extra passengers.
Though CASA insists that test flights were carried out to prove the aircraft's capabilities, performance engineers from Gulfstream American Corporation, its manufacturer told Australian operators the assessment must be wrong.
"If we thought it would fly 10 per cent heavier, we'd have certified it at that weight, sold a lot more planes, and made a lot more money," said a Gulfstream engineer.
As the man said if they could have certified the aircraft at a higher weight they would have. CASA should seriously look at these and the other old, old aircraft like the PA31, C402 etc who have been around 30 years or more as to their continued viability (SAFETY).
If the ATO disallowed well off individuals to claim tax breaks when operating an aircraft or charter company at a loss, the number of shady operators would be reduced. At the end of the day it’s all about money and knowing the right people. By that I am not implying the company concerned is shady but there are a number who would fit the bill.
Paul keep going with this, do not allow individuals with vested interests deter your reporting. It’s only individuals like you who bring incidents like this to the fore. Regardless of how well respected the owner of the company was or how knowledgeable on Shrikes he was, to my knowledge he was a LAME not a stress engineer a big difference. Perhaps you should frequent this forum more often and highlight through research the problems that GA has.
Five Aero Commanders are registered in Tasmania.
But Mr Gibson said, at this stage, there was no need to ground the fleet -- most of which were more than 30 years old. "We are aware of the similarities (between the accidents) but we need evidence of a real problem and at this stage we don't have that," Mr Gibson said.
Operators too are not worried about the safety of the planes, which are often described as the "workhorses of the sky".
Tasmanian Aero Club manager Joe Miller said he and his pilots had no concerns about flying their Aero Commanders, which is the sister aircraft to the one that went down in 2004.
So what sort of response did Peter Gibson expect from the operators?
Tasmanian Aero Club manager Joe Miller said he and his pilots had no concerns about flying their Aero Commanders, which is the sister aircraft to the one that went down in 2004.
"They are built like a brick ****house and we have not had any problems with wing fatigue or structural problems since we started operating them here," he said.
So succinctly put, a true GA manager.
Was the increase in MTOW requested to obtain an advantage in order to obtain a contract? The fact is that a number of these aircraft have broken up mid flight should question the wisdom of such an approval.
In the US, their country of origin, Shrikes are limited to a 3062kg maximum takeoff weight, but when they were imported here as used aircraft, the (then) Department of Aviation issued a "supplemental type certificate" allowing them to fly at up to 3357kg, the equivalent of three extra passengers.
Though CASA insists that test flights were carried out to prove the aircraft's capabilities, performance engineers from Gulfstream American Corporation, its manufacturer told Australian operators the assessment must be wrong.
"If we thought it would fly 10 per cent heavier, we'd have certified it at that weight, sold a lot more planes, and made a lot more money," said a Gulfstream engineer.
As the man said if they could have certified the aircraft at a higher weight they would have. CASA should seriously look at these and the other old, old aircraft like the PA31, C402 etc who have been around 30 years or more as to their continued viability (SAFETY).
If the ATO disallowed well off individuals to claim tax breaks when operating an aircraft or charter company at a loss, the number of shady operators would be reduced. At the end of the day it’s all about money and knowing the right people. By that I am not implying the company concerned is shady but there are a number who would fit the bill.
Paul keep going with this, do not allow individuals with vested interests deter your reporting. It’s only individuals like you who bring incidents like this to the fore. Regardless of how well respected the owner of the company was or how knowledgeable on Shrikes he was, to my knowledge he was a LAME not a stress engineer a big difference. Perhaps you should frequent this forum more often and highlight through research the problems that GA has.
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Would there have been further investigations into these two accidents if Paul had not written his article?
It’s only individuals like you who bring incidents like this to the fore.
What is the world coming to if believe we need to rely on the journalist profession to direct aviation safety in Australia.
The fact that these sort of comments are being expressed on PPRuNe is a sad indictment of CASA.
Di
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Yes, this is a sad indictment of CASA. Every now and then they need a bit of a clout to be reminded they are here to serve us not control us. When journos stop stirring the pot so vigorously that the regulators are embarrassed into a move, then democracy is in real trouble! I don't really think that Paul's article has forced CASA's hand. Remember CASA don't do crash investigation. There would have been an ATSB investigation anyway. Whether or not CASA acts on the recommendations is another question.
Paul Phelan has been accused of CASA-bashing in the past and his "Backlash" column in Australian Flyinghas copped its fair share of criticism. However, Paul's research is usually second to none in the industry and he's never taken a backward step. This is what we need more than anything: someone who's prepared to write their name to considered comment and thumb their nose at the regulators on our behalf.
As a GA scribbler myself, some of my work has also been changed by subs to something that was not intended. It is infuriating, but there's nothing that can be done about it. The subs and editors have the final say; we with the bylines get the public thumping. That's the industry!
Walrus
Disclaimer: Walrus has had work published by AF in the past and has had intermittent contact with Paul Phelan over the past three years or so. This post was edited to remove an embarrassing typo before anyone saw it.
Paul Phelan has been accused of CASA-bashing in the past and his "Backlash" column in Australian Flyinghas copped its fair share of criticism. However, Paul's research is usually second to none in the industry and he's never taken a backward step. This is what we need more than anything: someone who's prepared to write their name to considered comment and thumb their nose at the regulators on our behalf.
As a GA scribbler myself, some of my work has also been changed by subs to something that was not intended. It is infuriating, but there's nothing that can be done about it. The subs and editors have the final say; we with the bylines get the public thumping. That's the industry!
Walrus
Disclaimer: Walrus has had work published by AF in the past and has had intermittent contact with Paul Phelan over the past three years or so. This post was edited to remove an embarrassing typo before anyone saw it.
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someone help me here, why is VH-YJB mentioned in the article by mr phelan?
this particular aircraft was registered feb 2007 and had recently been brought over by G.A.M. from the states, is it safe to assume this aircraft had been adhering to the FAA MTOW for it`s previous life?
if so then this particular aircraft and accident doesn`t belong anywhere near the overweight shrike debate.
this particular aircraft was registered feb 2007 and had recently been brought over by G.A.M. from the states, is it safe to assume this aircraft had been adhering to the FAA MTOW for it`s previous life?
if so then this particular aircraft and accident doesn`t belong anywhere near the overweight shrike debate.
