R22 Corner
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On a minor point, do not manufacturers of all brands help out in investigations ? Boeing spring to mind. I think the rationale is something like "the guys who built it should know the answers to the questions we may have".
If so, I think it's a tad unfair to criticise FR on this one point if ALL aircraft manufacturers are doing it.
If so, I think it's a tad unfair to criticise FR on this one point if ALL aircraft manufacturers are doing it.
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To: The Nr Fairy
Participation of the manufacturers in an accident investigation is a normal thing however it has been determined that they may have a conflict of interest in providing reasons for failure. If you haven't already done so please read the newspaper article in my post to Vfrpilotpb dated 18, May 2001 above.
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The Cat
Participation of the manufacturers in an accident investigation is a normal thing however it has been determined that they may have a conflict of interest in providing reasons for failure. If you haven't already done so please read the newspaper article in my post to Vfrpilotpb dated 18, May 2001 above.
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The Cat
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I don't want to get into an argument which owes as much to elitism as it does to elucidation, but nobody can claim that Robinson enjoys a cosy relationship with the NTSB. He hates them like poison and they despise him equally, largely because they've never been able to find a single sane and reasonable excuse to ground him, despite best efforts.
[This message has been edited by t'aint natural (edited 21 May 2001).]
[This message has been edited by t'aint natural (edited 21 May 2001).]
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To: T'aint natural
I don’t know how someone living in London could be so sure of the “Hate-Hate” relationship between Robinson and the NTSB but let’s assume you are correct. In every loss of control accident the NTSB calls in Frank Robinson as their technical advisor and the final conclusion relative to the accident is that it is pilot error, and if it involves a training aircraft, Frank Robinson will invariably state that the R22 was not designed to be used as a trainer. Any attempt to steer the investigation to a design fault is strongly resisted by Frank Robinson or, one of his associates.
There was only one crash that was related to a manufacturing process and that is mentioned in the newspaper article that appears above. Every other accident was attributed to pilot error or, an inconclusive reason. The Robinson Helicopter is very reliable but it is my feeling that there is a design flaw in the rotorhead that allows these accidents to happen.
The safety reg that mandates the training of Robinson operators will soon be lifted and when that happens there will be a lot of poorly trained pilots ending up in a body bag because of not adhering to the FAA’s suggestion about flying out of trim and sideslipping and or, recovering from a zero G incident in accordance with the POH instructions.
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The Cat
I don’t know how someone living in London could be so sure of the “Hate-Hate” relationship between Robinson and the NTSB but let’s assume you are correct. In every loss of control accident the NTSB calls in Frank Robinson as their technical advisor and the final conclusion relative to the accident is that it is pilot error, and if it involves a training aircraft, Frank Robinson will invariably state that the R22 was not designed to be used as a trainer. Any attempt to steer the investigation to a design fault is strongly resisted by Frank Robinson or, one of his associates.
There was only one crash that was related to a manufacturing process and that is mentioned in the newspaper article that appears above. Every other accident was attributed to pilot error or, an inconclusive reason. The Robinson Helicopter is very reliable but it is my feeling that there is a design flaw in the rotorhead that allows these accidents to happen.
The safety reg that mandates the training of Robinson operators will soon be lifted and when that happens there will be a lot of poorly trained pilots ending up in a body bag because of not adhering to the FAA’s suggestion about flying out of trim and sideslipping and or, recovering from a zero G incident in accordance with the POH instructions.
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The Cat
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Frank Robinson has never made a secret of his hatred of the NTSB. To quote from a published interview with Robinson: "There are things you have to understand about the NTSB that go over most people's heads. James Hall (NTSB chairman appointed by Clinton) is appointed, paid off for his work for a political party. He helped run Al Gore's election campaign and in return he got a $120,000 job. He's a lawyer, in real estate I think, and he's got no background in aviation.
"When Hall was appointed he started changing a lot of policies, making a lot of noise and getting his face on television, obviously trying to make a name for himself politically. He attacked the ATR, the commuter airlines, the Boeing 737, and he's attacked me.
"Most of the NTSB investigators do a pretty good job, which is to establish the observed facts concerning the accident. So they make a wreckage distribution diagram, they document the pilot's credentials, the weather, all these kind of things. And then this is where it gets ridiculous. The Board is the one that then determines the probable cause. If you had professionals on the Board, that would make some sense. But the people on the Board have no background in aviation, no background in investigation, they're pure political hacks.
"So the people making the decisions have less knowledge of the business than the meanest private pilot. But they have the political power and they demand that the FAA follow their recommendations. If ever there was a tail wagging a dog it's the NTSB dictating policy to the FAA."
Robinson went on to detail at length the links between Hall and other figures in the Clinton administration and the Trial Lawyers' Association, which had for some years been pressing for full access to investigation material, and which Hall allowed them. Robinson went on: "He was not a member of the Trial Lawyers' Association and he was not an ambulance chaser or a tort lawyer. Most of his career has been spent working on various Congressmen's staff. What business does he have running the NTSB?"
All the accidents which the NTSB listed at that time as "unexplained" were the result of low RRPM, low-g manoeuvres or other known causes. In the same article, the pilot who formerly ran the Australian Army's helicopter training programme, and who is now a commercial operator, said: "There's nothing at all wrong with the R22, nil, nix, zero. People get killed flying Robinsons because they do dumb things, but because of the low standard of instruction, half the time they die not knowing why what they did was so dumb."
Alan Boswell, at the time a Bristows instructor, said: "The R22 is a fine aircraft and there is no mysterious problem. We have 18,000 hours' experience with the R22 at Bristows and it's given us fewer problems than the Bell 47 ever did."
"When Hall was appointed he started changing a lot of policies, making a lot of noise and getting his face on television, obviously trying to make a name for himself politically. He attacked the ATR, the commuter airlines, the Boeing 737, and he's attacked me.
"Most of the NTSB investigators do a pretty good job, which is to establish the observed facts concerning the accident. So they make a wreckage distribution diagram, they document the pilot's credentials, the weather, all these kind of things. And then this is where it gets ridiculous. The Board is the one that then determines the probable cause. If you had professionals on the Board, that would make some sense. But the people on the Board have no background in aviation, no background in investigation, they're pure political hacks.
"So the people making the decisions have less knowledge of the business than the meanest private pilot. But they have the political power and they demand that the FAA follow their recommendations. If ever there was a tail wagging a dog it's the NTSB dictating policy to the FAA."
Robinson went on to detail at length the links between Hall and other figures in the Clinton administration and the Trial Lawyers' Association, which had for some years been pressing for full access to investigation material, and which Hall allowed them. Robinson went on: "He was not a member of the Trial Lawyers' Association and he was not an ambulance chaser or a tort lawyer. Most of his career has been spent working on various Congressmen's staff. What business does he have running the NTSB?"
All the accidents which the NTSB listed at that time as "unexplained" were the result of low RRPM, low-g manoeuvres or other known causes. In the same article, the pilot who formerly ran the Australian Army's helicopter training programme, and who is now a commercial operator, said: "There's nothing at all wrong with the R22, nil, nix, zero. People get killed flying Robinsons because they do dumb things, but because of the low standard of instruction, half the time they die not knowing why what they did was so dumb."
Alan Boswell, at the time a Bristows instructor, said: "The R22 is a fine aircraft and there is no mysterious problem. We have 18,000 hours' experience with the R22 at Bristows and it's given us fewer problems than the Bell 47 ever did."
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To: T'aint natural
Frank Robinson may never have made a secret of his hatred of the NTSB but he does not let that stand in the way of participating in major accident investigations involving Robinson Helicopters. Whatever Jim Hall did to assist in Clintons' or Gores' campaign has absolutely nothing to do with his running the NTSB. Relative to his making changes so what. Every time a new person is appointed to a top management position he/she will try to make his/her mark on the organization. Hall left the organization several months ago and a woman who was the former assistant administrator is now running the NTSB. For your information if you are not already aware of it the NTSB is not just aviation specific. The NTSB monitors Highway Safety, Marine Safety, Aviation Safety and pipeline Safety as well as railroad safety. No one person can be knowledgeable in all of these areas. The director can have any type background and have no experience whatever in the work performed by the agency but he / she must be a good manager. When Jim Hall made most of his television presentations he was representing the agency in explaining the outcome of a major accident investigation.
He attacked the ATR, which crashed due to inadequate testing for ice accretion. He attacked the commuter airlines because of a very poor safety record and, he attacked the 737 because of a fault in the rudder control system that may have led to three crashes. I have no way of knowing why he attacked you unless you want to identify yourself and explain why you were attacked.
Regarding professionals on the accident investigation teams I would say you were wrong on that point as well. I know two individuals that investigate helicopter and aircraft accidents. One is an ex Marine CH-53 and CH-46 pilot who was also a squadron safety officer. He also worked on the Apache Program directing the office of safety. The other man is still flying in the National Guard and he has twenty years flying just about everything the US Army has in their inventory.
The FAA and the NTSB work for the same boss so naturally there is some difficulty in reaching a decision in an accident investigation. In the case of the Robinson accidents the NTSB wanted to ground them but the FAA who has the actual authority must admit they were in error in granting certification. Another point to consider is when the FAA granted certification it was not the helicopter directorate of the FAA that granted certification. It was the large aircraft certification branch, which is based in Seattle and has an office in Los Angeles. These people knew absolutely nothing about helicopters and were led by the Designated Engineering Rep who although he denies it was Frank Robinson or his agent.
What is wrong with the trial lawyers having access to accident investigations? This is a part of criminal and tort law in the USA and has been since the constitution was written. All lawyers have access to whatever evidence the prosecution has and when they don’t get it and this oversight is detected the defense or tort lawyers can request a mistrial or get the judge to seriously admonish the prosecution and possibly grant a new trial. If you haven’t read about it this is now happening in the Tim McVeigh death sentence.
It seems that you have determined that the unexplained accidents involving loss of control were attributed to low G, Low rotor RPM and/ or other known causes. This is not borne out in the NTSBs accident report. In any case, this translates into pilot error and not a basic design defect that allows these types of accidents to happen to both dumb and smart pilots.
Regarding the Australian pilots comment about low quality of instruction it would appear that the training programs in OZ don’t reflect the requirements specified by the FAA. That is not to say that pilots that have undergone this more stringent training are not capable of getting into trouble resulting in a rotor incursion or a mast bumping incident.
One final thought, do not confuse safety with reliability. Of the 35 or 36 loss of control accidents none related to reliability. There was only one crash that was reliability and quality related.
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The Cat
[This message has been edited by Lu Zuckerman (edited 22 May 2001).]
[This message has been edited by Lu Zuckerman (edited 23 May 2001).]
Frank Robinson may never have made a secret of his hatred of the NTSB but he does not let that stand in the way of participating in major accident investigations involving Robinson Helicopters. Whatever Jim Hall did to assist in Clintons' or Gores' campaign has absolutely nothing to do with his running the NTSB. Relative to his making changes so what. Every time a new person is appointed to a top management position he/she will try to make his/her mark on the organization. Hall left the organization several months ago and a woman who was the former assistant administrator is now running the NTSB. For your information if you are not already aware of it the NTSB is not just aviation specific. The NTSB monitors Highway Safety, Marine Safety, Aviation Safety and pipeline Safety as well as railroad safety. No one person can be knowledgeable in all of these areas. The director can have any type background and have no experience whatever in the work performed by the agency but he / she must be a good manager. When Jim Hall made most of his television presentations he was representing the agency in explaining the outcome of a major accident investigation.
He attacked the ATR, which crashed due to inadequate testing for ice accretion. He attacked the commuter airlines because of a very poor safety record and, he attacked the 737 because of a fault in the rudder control system that may have led to three crashes. I have no way of knowing why he attacked you unless you want to identify yourself and explain why you were attacked.
Regarding professionals on the accident investigation teams I would say you were wrong on that point as well. I know two individuals that investigate helicopter and aircraft accidents. One is an ex Marine CH-53 and CH-46 pilot who was also a squadron safety officer. He also worked on the Apache Program directing the office of safety. The other man is still flying in the National Guard and he has twenty years flying just about everything the US Army has in their inventory.
The FAA and the NTSB work for the same boss so naturally there is some difficulty in reaching a decision in an accident investigation. In the case of the Robinson accidents the NTSB wanted to ground them but the FAA who has the actual authority must admit they were in error in granting certification. Another point to consider is when the FAA granted certification it was not the helicopter directorate of the FAA that granted certification. It was the large aircraft certification branch, which is based in Seattle and has an office in Los Angeles. These people knew absolutely nothing about helicopters and were led by the Designated Engineering Rep who although he denies it was Frank Robinson or his agent.
What is wrong with the trial lawyers having access to accident investigations? This is a part of criminal and tort law in the USA and has been since the constitution was written. All lawyers have access to whatever evidence the prosecution has and when they don’t get it and this oversight is detected the defense or tort lawyers can request a mistrial or get the judge to seriously admonish the prosecution and possibly grant a new trial. If you haven’t read about it this is now happening in the Tim McVeigh death sentence.
It seems that you have determined that the unexplained accidents involving loss of control were attributed to low G, Low rotor RPM and/ or other known causes. This is not borne out in the NTSBs accident report. In any case, this translates into pilot error and not a basic design defect that allows these types of accidents to happen to both dumb and smart pilots.
Regarding the Australian pilots comment about low quality of instruction it would appear that the training programs in OZ don’t reflect the requirements specified by the FAA. That is not to say that pilots that have undergone this more stringent training are not capable of getting into trouble resulting in a rotor incursion or a mast bumping incident.
One final thought, do not confuse safety with reliability. Of the 35 or 36 loss of control accidents none related to reliability. There was only one crash that was reliability and quality related.
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The Cat
[This message has been edited by Lu Zuckerman (edited 22 May 2001).]
[This message has been edited by Lu Zuckerman (edited 23 May 2001).]
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Oh. You’ve changed feet then. I merely addressed the point you disputed, which is that Frank Robinson detests the NTSB. Your contention that Jim Hall was a good man is a non sequitur. I would reiterate that the NTSB is not and never was in Frank Robinson’s pocket.
I suggest you read my posting again. I do not say he attacked me. Virtually all of my posting was quoting Frank Robinson in a published article. It is Frank Robinson saying Jim Hall attacked him.
Incidentally, at the same time that Hall was trying to ground Robinson he was also trying to ground the 737, but the FAA managed to sit on him there, too.
If you think there’s nothing wrong with criminal lawyers having full access to investigation material, you must ponder what they do with the information. I’m sure you’re aware of the specious and nonsensical lawsuits which have been filed and won, often based on a small piece of evidence taken out of context and used to bamboozle a lay jury. That’s how Cessna and Piper production was halted, and who did that help? But that’s not a Robinson issue.
The Australian pilot was not talking about Australian training but US training. Most of the low RRPM/low-g accidents happened in the US. Three times over four years Frank Robinson petitioned the FAA to end the 50-hour rule, which meant that if a US fixed-wing instructor flew 50 hours in helicopters, he automatically became a helicopter instructor. It was only pressure from Robinson which changed that horrendous situation. This and other action, almost all of it initiated by Frank Robinson, have slashed the number and rate of Robinson accidents.
I suggest you read my posting again. I do not say he attacked me. Virtually all of my posting was quoting Frank Robinson in a published article. It is Frank Robinson saying Jim Hall attacked him.
Incidentally, at the same time that Hall was trying to ground Robinson he was also trying to ground the 737, but the FAA managed to sit on him there, too.
If you think there’s nothing wrong with criminal lawyers having full access to investigation material, you must ponder what they do with the information. I’m sure you’re aware of the specious and nonsensical lawsuits which have been filed and won, often based on a small piece of evidence taken out of context and used to bamboozle a lay jury. That’s how Cessna and Piper production was halted, and who did that help? But that’s not a Robinson issue.
The Australian pilot was not talking about Australian training but US training. Most of the low RRPM/low-g accidents happened in the US. Three times over four years Frank Robinson petitioned the FAA to end the 50-hour rule, which meant that if a US fixed-wing instructor flew 50 hours in helicopters, he automatically became a helicopter instructor. It was only pressure from Robinson which changed that horrendous situation. This and other action, almost all of it initiated by Frank Robinson, have slashed the number and rate of Robinson accidents.
Guest
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A question for you, Lu;
You say that the FAA have a vested interest in the R22 because they approved its certification in the first place -
how could any helicopter get through this process without being approved to fly with some degree of sideslip / out of balance condition?
My understanding of this kind of thing is that test pilots and engineers set up their test schedules to explore the safe boundaries of flight in particular aircraft, and make allowances for the 'average' pilot to give a safe margin for error when they lay down limits.
I find it very hard to believe that a machine that has been through this process would not have been trialled in such situations.
Are you saying that the FAA didn't do its job, and is now trying to cover up?
Perhaps we should call in Mulder and Scully.
You say that the FAA have a vested interest in the R22 because they approved its certification in the first place -
how could any helicopter get through this process without being approved to fly with some degree of sideslip / out of balance condition?
My understanding of this kind of thing is that test pilots and engineers set up their test schedules to explore the safe boundaries of flight in particular aircraft, and make allowances for the 'average' pilot to give a safe margin for error when they lay down limits.
I find it very hard to believe that a machine that has been through this process would not have been trialled in such situations.
Are you saying that the FAA didn't do its job, and is now trying to cover up?
Perhaps we should call in Mulder and Scully.
Guest
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To: T’aint natural
I made reference to your comment about the NTSB and Frank Robinson hating each other. I simply stated that even if this were true the NTSB and Frank Robinson never let this mutual hatred get in the way of participation in an accident investigation. This hatred as you called it placed the two participants into different corners. One participant was trying to find the cause and the other was steering the investigation away from investigating a fault that was common to all of the loss of control accidents and that thing was the rotorhead.
I never said that the NTSB was in Frank Robinson’s’ pocket. I stated and the newspaper article stated that he would exert undue influence in the investigation so that the ultimate finding was pilot error.
Regarding the FAA countering the findings of the NTSB on the 737 problem it is well known that the findings of the FAA fall on the side of the airlines. To ground the 737 would have been catastrophic to the airlines. The FAA would have performed a cost benefit analysis to determine the cost to the airlines against the cost of the airlines paying out insurance claims in the event of another 737 loss of control accident stemming from a defective rudder control system. In other words, it was cheaper to let another 737 crash than it was to ground the fleet.
Regarding your comment about what lawyers do with the evidentiary material provided by the prosecution my comment is that is what lawyers do and the law allows it. Regarding how they manipulate the evidence in presenting it to the jury that too is what lawyers do. In some cases murderers get off Scot-free and aircraft must be taken out of production because of higher insurance rates. That is a problem but it is a lawyers sworn duty to give his client the best defense possible even if he has to manipulate the evidence presented to the jury.
Whether Frank Robinson petitioned the FAA to change the 50-hour rule or not the findings of the Georgia Tech report was the ultimate device that changed the training of Robinson Pilots. It also placed restrictions on the flying of Robinson Helicopters. You stated that Frank Robinson’s’ involvement has reduced the rate of accidents. In the last year there have been four loss of control accidents and quite possibly a fifth and the NTSB is investigating all four or five of them to find a common cause. I think it is the rotor design and I have told the NTSB of my thoughts and in 1996 I composed a report and sent it to them.
Here is another point that you may not be aware of. Robinson Helicopters has been sued on many occasions stemming from crashes of their helicopters. In many cases the jury found on the side of the plaintiff and a substantial award was made. The plaintiffs’ lawyers never collected a cent. It seems that everything inside the Robinson factory is leased and I was told that he sold the building to his wife. Frank Robinson is a millionaire many times over but he keeps his money in offshore banks and it is therefore untouchable. On paper in the United States Frank Robinson is a pauper.
Me thinks thou doth protest too much (possible grammatical and spelling error). Either you like to argue which is not a bad characteristic or, you have a vested interest in Robinson Helicopters.
To: Arm out the window
My answer to the first paragraph in your post is “YES”
In answer to your second question, all helicopters must be tested for sideslip and out of trim flight.
The out of trim and sideslip is not dictated by the test pilots and engineers it is a requirement of Advisory Circular 27-1 CERTIFICATION OF NORMAL CATEGORY ROTORCRAFT. The helicopter manufacturer is required to demonstrate these requirements in order to gain certification.
The question that I have is if the R22 was certified as being able to demonstrate sideslip and out of trim flight why didn’t the test pilots discover that these maneuvers caused severe flapping loads that could lead to mast bumping and /or rotor incursion. The basis for my question is that in January of 1995 the FAA mandated that the R22 and R44 be restricted from flying out of trim at any time and that the pilot should avoid sideslip during flight. The reason was to avoid high flapping loads that would result in mast bumping and / or fuselage incursion.
Nothing in the design was changed but after 1995 the helicopters were restricted from flying under the same conditions under which they were certificated.
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The Cat
I made reference to your comment about the NTSB and Frank Robinson hating each other. I simply stated that even if this were true the NTSB and Frank Robinson never let this mutual hatred get in the way of participation in an accident investigation. This hatred as you called it placed the two participants into different corners. One participant was trying to find the cause and the other was steering the investigation away from investigating a fault that was common to all of the loss of control accidents and that thing was the rotorhead.
I never said that the NTSB was in Frank Robinson’s’ pocket. I stated and the newspaper article stated that he would exert undue influence in the investigation so that the ultimate finding was pilot error.
Regarding the FAA countering the findings of the NTSB on the 737 problem it is well known that the findings of the FAA fall on the side of the airlines. To ground the 737 would have been catastrophic to the airlines. The FAA would have performed a cost benefit analysis to determine the cost to the airlines against the cost of the airlines paying out insurance claims in the event of another 737 loss of control accident stemming from a defective rudder control system. In other words, it was cheaper to let another 737 crash than it was to ground the fleet.
Regarding your comment about what lawyers do with the evidentiary material provided by the prosecution my comment is that is what lawyers do and the law allows it. Regarding how they manipulate the evidence in presenting it to the jury that too is what lawyers do. In some cases murderers get off Scot-free and aircraft must be taken out of production because of higher insurance rates. That is a problem but it is a lawyers sworn duty to give his client the best defense possible even if he has to manipulate the evidence presented to the jury.
Whether Frank Robinson petitioned the FAA to change the 50-hour rule or not the findings of the Georgia Tech report was the ultimate device that changed the training of Robinson Pilots. It also placed restrictions on the flying of Robinson Helicopters. You stated that Frank Robinson’s’ involvement has reduced the rate of accidents. In the last year there have been four loss of control accidents and quite possibly a fifth and the NTSB is investigating all four or five of them to find a common cause. I think it is the rotor design and I have told the NTSB of my thoughts and in 1996 I composed a report and sent it to them.
Here is another point that you may not be aware of. Robinson Helicopters has been sued on many occasions stemming from crashes of their helicopters. In many cases the jury found on the side of the plaintiff and a substantial award was made. The plaintiffs’ lawyers never collected a cent. It seems that everything inside the Robinson factory is leased and I was told that he sold the building to his wife. Frank Robinson is a millionaire many times over but he keeps his money in offshore banks and it is therefore untouchable. On paper in the United States Frank Robinson is a pauper.
Me thinks thou doth protest too much (possible grammatical and spelling error). Either you like to argue which is not a bad characteristic or, you have a vested interest in Robinson Helicopters.
To: Arm out the window
My answer to the first paragraph in your post is “YES”
In answer to your second question, all helicopters must be tested for sideslip and out of trim flight.
The out of trim and sideslip is not dictated by the test pilots and engineers it is a requirement of Advisory Circular 27-1 CERTIFICATION OF NORMAL CATEGORY ROTORCRAFT. The helicopter manufacturer is required to demonstrate these requirements in order to gain certification.
The question that I have is if the R22 was certified as being able to demonstrate sideslip and out of trim flight why didn’t the test pilots discover that these maneuvers caused severe flapping loads that could lead to mast bumping and /or rotor incursion. The basis for my question is that in January of 1995 the FAA mandated that the R22 and R44 be restricted from flying out of trim at any time and that the pilot should avoid sideslip during flight. The reason was to avoid high flapping loads that would result in mast bumping and / or fuselage incursion.
Nothing in the design was changed but after 1995 the helicopters were restricted from flying under the same conditions under which they were certificated.
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The Cat
Guest
Posts: n/a
Don’t be paranoid, Lu. I have no vested interest beyond hanging my butt on them. Do you have a vested interest in doing him down?
Every manufacturer is invited to participate in accident investigations. Frank Robinson’s establishment of the factory safety course and his in-house insurance programme (which offered discounts on condition of training in certain areas) were established before Georgia Tech, before the promulgation of any FARs. It was these, plus the change in the 50-hour rule, which reduced the accident rate (from 6 per 1000,000 in 1990 to 1.2 per 100,000 in 1995). He has always gone “naked,” ie has carried no liability insurance and has fought every lawsuit. If you produce aircraft you’re going to get lawsuits, full stop. And you’re going to lose them, guilty or not.
It’s about time this airy notion that you can be flying along happily in an Robinson and all of a sudden the rotor takes off and flies through the tail boom was put to rest. The NTSB certainly have given up on it. I have seen correspondence between the Board and Robinson congratulating him on being “off our radar screen.” The rotor blade will remove the tail boom for you if the RRPM falls below a certain value, by which time the jig’s up and you have no further use for a tail boom anyway. It will also whip the boom off if you respond wrongly in a low-g situation. It’s a characteristics of a two-bladed rotor. The US military produced information films on it for Vietnam pilots in the 60s. Robinson didn’t invent it. Thanks to Robinson, helicopters were introduced to a massive audience of low-time pilots, and that’s where the problem is, not in the head.
There are good sound reasons why Robinsons are the most popular helicopters in the world, outselling all other civilian helicopters put together. It’s not because we’re all stupid, or venal, or careless. It’s because they are sound machines which do the job cost-effectively and safely, if you don’t take a lend of them. They’ve become established despite the best efforts of other manufacturers to foster doubt and uncertainty, and despite the efforts of snobbish pilots flying larger machines, usually paid for by someone else, to denigrate them.
Every manufacturer is invited to participate in accident investigations. Frank Robinson’s establishment of the factory safety course and his in-house insurance programme (which offered discounts on condition of training in certain areas) were established before Georgia Tech, before the promulgation of any FARs. It was these, plus the change in the 50-hour rule, which reduced the accident rate (from 6 per 1000,000 in 1990 to 1.2 per 100,000 in 1995). He has always gone “naked,” ie has carried no liability insurance and has fought every lawsuit. If you produce aircraft you’re going to get lawsuits, full stop. And you’re going to lose them, guilty or not.
It’s about time this airy notion that you can be flying along happily in an Robinson and all of a sudden the rotor takes off and flies through the tail boom was put to rest. The NTSB certainly have given up on it. I have seen correspondence between the Board and Robinson congratulating him on being “off our radar screen.” The rotor blade will remove the tail boom for you if the RRPM falls below a certain value, by which time the jig’s up and you have no further use for a tail boom anyway. It will also whip the boom off if you respond wrongly in a low-g situation. It’s a characteristics of a two-bladed rotor. The US military produced information films on it for Vietnam pilots in the 60s. Robinson didn’t invent it. Thanks to Robinson, helicopters were introduced to a massive audience of low-time pilots, and that’s where the problem is, not in the head.
There are good sound reasons why Robinsons are the most popular helicopters in the world, outselling all other civilian helicopters put together. It’s not because we’re all stupid, or venal, or careless. It’s because they are sound machines which do the job cost-effectively and safely, if you don’t take a lend of them. They’ve become established despite the best efforts of other manufacturers to foster doubt and uncertainty, and despite the efforts of snobbish pilots flying larger machines, usually paid for by someone else, to denigrate them.
Guest
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Hmmm.
I see where you're coming from, Lu, but I'm also skeptical that an aircraft can get through the certification process without being subjected to amounts of out-of-balance flying and sideslip which would have to have shown up any untoward characteristics long before the machine was allowed to be sold commercially.
Surely in sidewards flight the sideways airflow component must have been at least 20 kts or so (I don't know what the flight manual limit is, having not flown the R22, but I'm guessing it must be in that order of magnitude?).
If that's the case, the amount and direction of flapping associated with that must brought the aircraft into the 'danger zone', for want of better words.
I see where you're coming from, Lu, but I'm also skeptical that an aircraft can get through the certification process without being subjected to amounts of out-of-balance flying and sideslip which would have to have shown up any untoward characteristics long before the machine was allowed to be sold commercially.
Surely in sidewards flight the sideways airflow component must have been at least 20 kts or so (I don't know what the flight manual limit is, having not flown the R22, but I'm guessing it must be in that order of magnitude?).
If that's the case, the amount and direction of flapping associated with that must brought the aircraft into the 'danger zone', for want of better words.
Guest
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To: Arm out the window
You said,
“Hmmm.
I see where you're coming from, Lou, but I'm also skeptical that an aircraft can get through the certification process without being subjected to amounts of out-of-balance flying and sideslip which would have to have shown up any untoward characteristics long before the machine was allowed to be sold commercially.
Surely in sideward flight the sideways airflow component must have been at least 20 kts or so (I don't know what the flight manual limit is, having not flown the R22, but I'm guessing it must be in that order of magnitude?).
If that's the case, the amount and direction of flapping associated with that must brought the aircraft into the 'danger zone', for want of better words”.
That is exactly my point. In order to certificate, the helicopter had to comply with the requirements of FAA Advisory Circular 27-1 which state that the helicopter had to demonstrate a sideslip of 90-degrees left and right at .6VNE and 10-degrees left and right out of trim at the same speed. Assuming these tests were demonstrated they should have realized that the flapping loads were excessive and made note of it in the test reports handed over to the FAA. You must also understand that the FAA does not oversee all of these tests. The tests are conducted and documented by what is known as a DER (Designated Engineering Representative). These individuals are employees of Robinson Helicopters and in some cases are officers of the company who have a vested interest in getting the helicopter certified. Frank Robinson was a DER for some time on the R22 and R44 certification programs. How is that for a conflict of interest?
During the timeframe of certification to the issuance of the FAA restrictions there were 31 rotor incursion / mast separation accidents. After the issuance of the restrictions and the implementation of the higher training standards there were no rotor incursion/mast separation accidents until last year where there were four and this year possibly one.
The Georgia Tech investigation pointed out that sideslip and out of trim flight could induce these high flapping excursions and result in mast bumping or rotor incursions. This was mainly a computer analysis and it pointed out the problem. Why did they discover this fact and the actual certification tests did not?
I pointed out the following on another post. The design of the Robinson head incorporates an internal droop stop, which is called a tusk. The tusk contacts a bolt in the rotorhead, which prevents the blade from drooping when at rest. Upon spin-up and the introduction of collective the blades cone up and the tusk moves away from the limit stop (bolt) thus allowing the blade to flap. During normal maneuvering the blade will always be in the flapping zone. However when the rotor head is placed in conditions of violent maneuvering or the flapping excursion exceeds the normal range the tusk will contact the stop bolt. When this happens the flapping energy of the blade is mechanically coupled to the rotorhead and it causes an instantaneous teeter taking the rotor system out of its’ rotational plane. If the kinetic energy of the opposite blade is strong enough then the blade will bend and most likely hit the tail boom or the fuselage in the cabin area. This can’t happen on a bell blade because it can’t flap.
Another point to consider is that when the blades flap they want to lead and lag. This tendency to lead and lag is partially absorbed in the inplane bending of the blades but the primary lead lag loads are reacted by the cone hinges and in part by the teeter hinge. With the introduction of the high flapping excursions, the energy of the lead lag increases plus and minus (inplane) and this may cause the blades to twist and aerodynamically fly out of plane. Also, this can exert higher than normal twisting loads on the rotor mast, all of which can cause mast bumping, mast separation or rotor incursion.
Again I say this can’t happen on a Bell system because the blades don’t flap.
The requirements of FAA AC 27-1 state that when a new and unusual design is proposed for certification that design must undergo a high degree of scrutiny and it must be proven to the FAA that this new design is both safe and reliable. The Robinson rotorhead meets these criteria but the question begs asking did they comply with this requirement of 27-1?
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The Cat
You said,
“Hmmm.
I see where you're coming from, Lou, but I'm also skeptical that an aircraft can get through the certification process without being subjected to amounts of out-of-balance flying and sideslip which would have to have shown up any untoward characteristics long before the machine was allowed to be sold commercially.
Surely in sideward flight the sideways airflow component must have been at least 20 kts or so (I don't know what the flight manual limit is, having not flown the R22, but I'm guessing it must be in that order of magnitude?).
If that's the case, the amount and direction of flapping associated with that must brought the aircraft into the 'danger zone', for want of better words”.
That is exactly my point. In order to certificate, the helicopter had to comply with the requirements of FAA Advisory Circular 27-1 which state that the helicopter had to demonstrate a sideslip of 90-degrees left and right at .6VNE and 10-degrees left and right out of trim at the same speed. Assuming these tests were demonstrated they should have realized that the flapping loads were excessive and made note of it in the test reports handed over to the FAA. You must also understand that the FAA does not oversee all of these tests. The tests are conducted and documented by what is known as a DER (Designated Engineering Representative). These individuals are employees of Robinson Helicopters and in some cases are officers of the company who have a vested interest in getting the helicopter certified. Frank Robinson was a DER for some time on the R22 and R44 certification programs. How is that for a conflict of interest?
During the timeframe of certification to the issuance of the FAA restrictions there were 31 rotor incursion / mast separation accidents. After the issuance of the restrictions and the implementation of the higher training standards there were no rotor incursion/mast separation accidents until last year where there were four and this year possibly one.
The Georgia Tech investigation pointed out that sideslip and out of trim flight could induce these high flapping excursions and result in mast bumping or rotor incursions. This was mainly a computer analysis and it pointed out the problem. Why did they discover this fact and the actual certification tests did not?
I pointed out the following on another post. The design of the Robinson head incorporates an internal droop stop, which is called a tusk. The tusk contacts a bolt in the rotorhead, which prevents the blade from drooping when at rest. Upon spin-up and the introduction of collective the blades cone up and the tusk moves away from the limit stop (bolt) thus allowing the blade to flap. During normal maneuvering the blade will always be in the flapping zone. However when the rotor head is placed in conditions of violent maneuvering or the flapping excursion exceeds the normal range the tusk will contact the stop bolt. When this happens the flapping energy of the blade is mechanically coupled to the rotorhead and it causes an instantaneous teeter taking the rotor system out of its’ rotational plane. If the kinetic energy of the opposite blade is strong enough then the blade will bend and most likely hit the tail boom or the fuselage in the cabin area. This can’t happen on a bell blade because it can’t flap.
Another point to consider is that when the blades flap they want to lead and lag. This tendency to lead and lag is partially absorbed in the inplane bending of the blades but the primary lead lag loads are reacted by the cone hinges and in part by the teeter hinge. With the introduction of the high flapping excursions, the energy of the lead lag increases plus and minus (inplane) and this may cause the blades to twist and aerodynamically fly out of plane. Also, this can exert higher than normal twisting loads on the rotor mast, all of which can cause mast bumping, mast separation or rotor incursion.
Again I say this can’t happen on a Bell system because the blades don’t flap.
The requirements of FAA AC 27-1 state that when a new and unusual design is proposed for certification that design must undergo a high degree of scrutiny and it must be proven to the FAA that this new design is both safe and reliable. The Robinson rotorhead meets these criteria but the question begs asking did they comply with this requirement of 27-1?
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The Cat
Guest
Posts: n/a
To: Imlanphere
On a flexrotor system such as that on large Sikorsky helicopters the rotorhead had a droop stop and a cone stop for each blade. These stops are centrifugally operated. When the head spins up the first stop that comes out is the cone stop. This allows the blade to cone when collective is added. When the weight of the blade comes off of the droop stop it will also be moved outward due to centrifugal force and this allows the blade to flap downward below the pure radial or stopped condition. If one of the droop stops fails to come out of the static position one of the blades will have restricted flapping range. If in the process of maneuvering that blade contacts the droop stop the kinetic energy in the blade will be expended in the bending mode. The first thing the pilot will feel is a very hard series of bumps and the next thing he is talking to St. Peter because the blade entered the cabin or it hit the tail boom.
On the Robinson the rotorhead is free to both pivot on the teeter hinge and the blades are free to flap on the cone hinges. On the Sikorsky head the blades can flap up (over the radial position) and flap down (below) the radial position. On the Robinson the blades can not flap below the radial position without contacting the tusk (droop stop). On the Sikorsky the energy of the blade will cause it to bend when hitting the droop stop. On the Robinson the rotorhead is free to teeter but when a blade is flapping violently the tusk will contact the stop and force the rotorhead to teeter taking it out of the plane of rotation. If this does not happen the blade will bend most likely resulting in a fuselage strike.
I don’t know if this phenomenon has ever been investigated but if you look at a drawing of the Robinson Rotorhead it becomes a simple matter of mechanics and physics.
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The Cat
On a flexrotor system such as that on large Sikorsky helicopters the rotorhead had a droop stop and a cone stop for each blade. These stops are centrifugally operated. When the head spins up the first stop that comes out is the cone stop. This allows the blade to cone when collective is added. When the weight of the blade comes off of the droop stop it will also be moved outward due to centrifugal force and this allows the blade to flap downward below the pure radial or stopped condition. If one of the droop stops fails to come out of the static position one of the blades will have restricted flapping range. If in the process of maneuvering that blade contacts the droop stop the kinetic energy in the blade will be expended in the bending mode. The first thing the pilot will feel is a very hard series of bumps and the next thing he is talking to St. Peter because the blade entered the cabin or it hit the tail boom.
On the Robinson the rotorhead is free to both pivot on the teeter hinge and the blades are free to flap on the cone hinges. On the Sikorsky head the blades can flap up (over the radial position) and flap down (below) the radial position. On the Robinson the blades can not flap below the radial position without contacting the tusk (droop stop). On the Sikorsky the energy of the blade will cause it to bend when hitting the droop stop. On the Robinson the rotorhead is free to teeter but when a blade is flapping violently the tusk will contact the stop and force the rotorhead to teeter taking it out of the plane of rotation. If this does not happen the blade will bend most likely resulting in a fuselage strike.
I don’t know if this phenomenon has ever been investigated but if you look at a drawing of the Robinson Rotorhead it becomes a simple matter of mechanics and physics.
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The Cat
Guest
Posts: n/a
I see exactly what you are saying Lu, having worked on the R22 it is easy to visualise.
If anyone has ever pushed the forward blade of an R22 up, all the way, the slightest wind, and the aft blade will contact the tailboom. So will the momentum and the rotation, I can see exactly how this could occur.
Deviating from the point slightly, Lu do you ever visit the U.K?
If anyone has ever pushed the forward blade of an R22 up, all the way, the slightest wind, and the aft blade will contact the tailboom. So will the momentum and the rotation, I can see exactly how this could occur.
Deviating from the point slightly, Lu do you ever visit the U.K?
Guest
Posts: n/a
To: HeliEng
Strange that you ask. I will be in the UK this Sunday morning but I will only be there for 1-½ hours waiting for a connecting flight to Munich. I will be on a short term consulting job with Fairchild Dornier working on the hydraulic system of the FD 728. On my return there is another 1-½ hour layover on my way back to Canada.
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The Cat
Strange that you ask. I will be in the UK this Sunday morning but I will only be there for 1-½ hours waiting for a connecting flight to Munich. I will be on a short term consulting job with Fairchild Dornier working on the hydraulic system of the FD 728. On my return there is another 1-½ hour layover on my way back to Canada.
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The Cat
Guest
Posts: n/a
Lu, on the R22 the teetering hinge facilitates downward flapping of the blades - the limit of this flapping is the rotor hub to mast clearance. I can't envision why a blade would be prone to flapping violently downward on its coning hinge. Some coning should be present in all flight regimes - thus maintaining clearance at the droop stop.
Guest
Posts: n/a
Just a wild guess.
The Robinson has five 'hinges' that will accommodate vertical motion of the two blade tips.
There is one teetering hinge.
There are two coning hinges.
The two blades can structurally bend in a vertical direction.
This is more flapping/teetering 'hinges' than any other helicopter has.
The degree of teetering rotation is probable comparable to other 2-bladed helicopters.
The coning hinge will allow an additional 3-degrees of downward movement over that of fixed pre-coned hubs.
What is left is the flexure of the blades and the clearance between the horizontal rotor disk and the boom.
Might it be that, during an unusual situation, there is a self-excitation that takes place amongst all these five 'hinges' and this causes one of the tips to drop excessively low for a portion of one revolution?
Just a wild guess.
The Robinson has five 'hinges' that will accommodate vertical motion of the two blade tips.
There is one teetering hinge.
There are two coning hinges.
The two blades can structurally bend in a vertical direction.
This is more flapping/teetering 'hinges' than any other helicopter has.
The degree of teetering rotation is probable comparable to other 2-bladed helicopters.
The coning hinge will allow an additional 3-degrees of downward movement over that of fixed pre-coned hubs.
What is left is the flexure of the blades and the clearance between the horizontal rotor disk and the boom.
Might it be that, during an unusual situation, there is a self-excitation that takes place amongst all these five 'hinges' and this causes one of the tips to drop excessively low for a portion of one revolution?
Just a wild guess.
Guest
Posts: n/a
To: HeliEng
If my company gets the contract (90% sure) for the A-380 I will be spending a lot of time in France and England. On this trip the ticket was booked for me and I have to keep to the schedule. On the A-380 program I will set my own schedule which will give us the opportunity to get together. Send me your Email address.
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The Cat
If my company gets the contract (90% sure) for the A-380 I will be spending a lot of time in France and England. On this trip the ticket was booked for me and I have to keep to the schedule. On the A-380 program I will set my own schedule which will give us the opportunity to get together. Send me your Email address.
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The Cat