Certification of Robinson Helicopters (incl post by Frank Robinson)
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To: 430 Driver
Just imagine if it happened to you without an instructor. If you put it into autorotation and the centrifugal twisting moment didn't return the tail rotor blades to neutral pitch, where would you be?
It just proves that Murphys' law can strike at any time. A similar fracture occured on the cyclic of an R22 in California and the helicopter crashed. Robinson ended up strengthening the assembly.
If Krylian is reading this, Robinson didn't get it right the first time and it took the loss of a pilot and a helicopter to bring it to their attention. Many posts ago I mentioned to a pilot that wanted to purchase an R44 Raven with hydraulic boost. I told him to have the dealer show him if Robinson had modified the upper controls or, if they were still the same as the original R44. If they are the same, the same problem of control linkage failure can occur.
I believe the cyclic failed due to vibratory feedback in the control system. By putting hydraulics in the R44 the servos will eliminate the feedback into the lower control system thus exposing the upper controls to even greater loads due to the blockage provided by the servos. The pilot however will notice a great improvement over the standard R44 and not pay any attention to what is going on in the control system above him.
As an aside I would make this suggestion to any pilot that flies a Bell helicopter with NodaMatic transmission suspension. This suspension provides the smooth ride that all Bell pilots talk about.
If it is possible to remove an inspection panel from the structure containing the transmission assembly have someone look into the panel opening when in flight. It will scare the hell out of you. The dynamic system is beating itself to death but the passengers and pilots get an extremely smooth ride.
To: Kyrilian, let's see if they get it right the first time. Also, let's see if the hydraulics system designers coordinated their efforts with the control and aerodynamics engineers. Not like the engineer at Sikorsky (see above).
To Try_Cyclic
You tell me that I am blinded by my beliefs and will not let any counter argument sway me. From my point of view, you are in the same boat blinded by your loyalty to Robinson helicopters. This is commendable but how do you feel when I tell you that there were 32 loss of control accidents involving rotor loss or rotor incursion with a lot of loss of life and all of it was attributed to pilot error. There were many other loss of control accidents and all were attributed to pilot error according to Jim Hall of the NTSB. Did you read the newspaper article I posted above. It pretty well explains why it is always pilot error.
Jim Hall of the NTSB stated that there may have been more in Europe and in other countries where the FAA and NTSB have no jurisdiction. However, if an investigation was made by the local authorities the FAA and NTSB may not have been there but you know who or his representatives were.
Here we go again. On a Bell if the rotor flaps there is no effect on the phase angle but there is an effect due to pitch coupling which does not relate to the phase angle. Read my posts above. If using your words the Robinson blades flap around the teeter point then there is no pitch coupling. The only way you get pitch coupling on a Robinson is if the blades flap (Move up or down)on the cone hinge in relation to the rotorhead. Other wise it moves as a composite assembly and there is no pitch coupling.
Take a close look at a Robinson swashplate. The 18 degree (approximate) difference is caused by the fact that the pitch horn can't pass the cone hinge. When the blades are disposed over the lateral axis on both a Bell and a Robinson, move the cyclic in any direction and both swashplates move in the same manner.
When the blades on the Bell are in the lateral position and the pilot inputs forward cyclic the pitch horn/pitch link is over the lowest point on the swashplate which means that the advancing blade is at its lowest pitch point. Ths means that due to precession the blade will flap down over the nose.
Now, check the Robinson with the blades in the same position. Move the cyclic so that the swash plate is at its; lowest point over the longitudinal axis. Check where the pitch horn/pitch link are. In order to reach the lowest point the rotating swashplate must rotate another 18 degrees (approximately).
Since the pitch change on the advancing blade is continuing during this 18 degree transition it will not achieve its' lowest pitch until the blade has moved 18 degrees (approximately) past the lateral axis.
With a phase angle of 90 degrees the blades will dip 90 degrees later to the left after the maximum input is made. How difficult is it to understand this scenario?
The two websites that I located are identical. The text was prepared by Paul Cantrell. So what. I stated that the websites were pro Robinson and most likely had the support of Robinson.
The point I made on a previous post was that they discussed the Robinson rotor system and compared it to a Bell 206 rotor head. The text lead you into the discussion of gyroscopic precession and said that it applied to both helicopters. However, when they presented a diagram showing input vs results they used a diagram for a Bell Helicopter and not a Robinson. To do otherwise would expose the secret and it would be contrary to the Robinson training program. At least, those are my feelings.
In a previous post I asked for a descripton in laymans terms how the Robinson blades move in the same way as those of a Bell 206 and achieve a 90 degree phase angle and, dip down over the nose.
Can you provide the explanation and it can come from a Robinson training manual if you wish.
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The Cat
[This message has been edited by Lu Zuckerman (edited 26 November 2000).]
[This message has been edited by Lu Zuckerman (edited 26 November 2000).]
Just imagine if it happened to you without an instructor. If you put it into autorotation and the centrifugal twisting moment didn't return the tail rotor blades to neutral pitch, where would you be?
It just proves that Murphys' law can strike at any time. A similar fracture occured on the cyclic of an R22 in California and the helicopter crashed. Robinson ended up strengthening the assembly.
If Krylian is reading this, Robinson didn't get it right the first time and it took the loss of a pilot and a helicopter to bring it to their attention. Many posts ago I mentioned to a pilot that wanted to purchase an R44 Raven with hydraulic boost. I told him to have the dealer show him if Robinson had modified the upper controls or, if they were still the same as the original R44. If they are the same, the same problem of control linkage failure can occur.
I believe the cyclic failed due to vibratory feedback in the control system. By putting hydraulics in the R44 the servos will eliminate the feedback into the lower control system thus exposing the upper controls to even greater loads due to the blockage provided by the servos. The pilot however will notice a great improvement over the standard R44 and not pay any attention to what is going on in the control system above him.
As an aside I would make this suggestion to any pilot that flies a Bell helicopter with NodaMatic transmission suspension. This suspension provides the smooth ride that all Bell pilots talk about.
If it is possible to remove an inspection panel from the structure containing the transmission assembly have someone look into the panel opening when in flight. It will scare the hell out of you. The dynamic system is beating itself to death but the passengers and pilots get an extremely smooth ride.
To: Kyrilian, let's see if they get it right the first time. Also, let's see if the hydraulics system designers coordinated their efforts with the control and aerodynamics engineers. Not like the engineer at Sikorsky (see above).
To Try_Cyclic
You tell me that I am blinded by my beliefs and will not let any counter argument sway me. From my point of view, you are in the same boat blinded by your loyalty to Robinson helicopters. This is commendable but how do you feel when I tell you that there were 32 loss of control accidents involving rotor loss or rotor incursion with a lot of loss of life and all of it was attributed to pilot error. There were many other loss of control accidents and all were attributed to pilot error according to Jim Hall of the NTSB. Did you read the newspaper article I posted above. It pretty well explains why it is always pilot error.
Jim Hall of the NTSB stated that there may have been more in Europe and in other countries where the FAA and NTSB have no jurisdiction. However, if an investigation was made by the local authorities the FAA and NTSB may not have been there but you know who or his representatives were.
Here we go again. On a Bell if the rotor flaps there is no effect on the phase angle but there is an effect due to pitch coupling which does not relate to the phase angle. Read my posts above. If using your words the Robinson blades flap around the teeter point then there is no pitch coupling. The only way you get pitch coupling on a Robinson is if the blades flap (Move up or down)on the cone hinge in relation to the rotorhead. Other wise it moves as a composite assembly and there is no pitch coupling.
Take a close look at a Robinson swashplate. The 18 degree (approximate) difference is caused by the fact that the pitch horn can't pass the cone hinge. When the blades are disposed over the lateral axis on both a Bell and a Robinson, move the cyclic in any direction and both swashplates move in the same manner.
When the blades on the Bell are in the lateral position and the pilot inputs forward cyclic the pitch horn/pitch link is over the lowest point on the swashplate which means that the advancing blade is at its lowest pitch point. Ths means that due to precession the blade will flap down over the nose.
Now, check the Robinson with the blades in the same position. Move the cyclic so that the swash plate is at its; lowest point over the longitudinal axis. Check where the pitch horn/pitch link are. In order to reach the lowest point the rotating swashplate must rotate another 18 degrees (approximately).
Since the pitch change on the advancing blade is continuing during this 18 degree transition it will not achieve its' lowest pitch until the blade has moved 18 degrees (approximately) past the lateral axis.
With a phase angle of 90 degrees the blades will dip 90 degrees later to the left after the maximum input is made. How difficult is it to understand this scenario?
The two websites that I located are identical. The text was prepared by Paul Cantrell. So what. I stated that the websites were pro Robinson and most likely had the support of Robinson.
The point I made on a previous post was that they discussed the Robinson rotor system and compared it to a Bell 206 rotor head. The text lead you into the discussion of gyroscopic precession and said that it applied to both helicopters. However, when they presented a diagram showing input vs results they used a diagram for a Bell Helicopter and not a Robinson. To do otherwise would expose the secret and it would be contrary to the Robinson training program. At least, those are my feelings.
In a previous post I asked for a descripton in laymans terms how the Robinson blades move in the same way as those of a Bell 206 and achieve a 90 degree phase angle and, dip down over the nose.
Can you provide the explanation and it can come from a Robinson training manual if you wish.
------------------
The Cat
[This message has been edited by Lu Zuckerman (edited 26 November 2000).]
[This message has been edited by Lu Zuckerman (edited 26 November 2000).]
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A number of people in this thread have talked about either the cyclic or the mast being rigged to prevent tailrotor translating tendency.As far as I am aware its purely pilot input counteracting this on the R22, unsure about R44.
Maybe someone could confirm this.
Maybe someone could confirm this.
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To: Arm the floats
I can't tell you if the mast is tilted or not. Just like you I read it on posts here on PPRuNe and on Just Helicopters. However I can tell you that there is no countering of tail rotor thrust rigged int the control system. When the cyclic is in the rigged neutral position it is in the middle of fore and aft movement and slightly to the right of the longitudinal center line. With the cyclic in this position the swash plate is flat and not biased to the left.
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The Cat
I can't tell you if the mast is tilted or not. Just like you I read it on posts here on PPRuNe and on Just Helicopters. However I can tell you that there is no countering of tail rotor thrust rigged int the control system. When the cyclic is in the rigged neutral position it is in the middle of fore and aft movement and slightly to the right of the longitudinal center line. With the cyclic in this position the swash plate is flat and not biased to the left.
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The Cat
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For Your Information - pulled off the HAI website today -
"FAA Requests Comments on Final Rule Adopting Emergency Airworthiness Directive for Robinson R22"
The Federal Aviation Admin. published in the Federal Register of November 7, 2000, an amendment adopting Airworthiness Directive (AD)2000-20-51,, which was sent previously to all known U.S. owners and operators
of Robinson Helicopter Co. Model R-22 helicopters by individual letters.
This AD requires checking the yoke half assembly for any crack and replacing a cracked yoke assembly before further flight. This AD also requires replacing certain yokes with airworthy yokes before further flight
after January 1, 2001. This AD is prompted by the discovery of cracks in the yoke.
Comments?? Lu?
"FAA Requests Comments on Final Rule Adopting Emergency Airworthiness Directive for Robinson R22"
The Federal Aviation Admin. published in the Federal Register of November 7, 2000, an amendment adopting Airworthiness Directive (AD)2000-20-51,, which was sent previously to all known U.S. owners and operators
of Robinson Helicopter Co. Model R-22 helicopters by individual letters.
This AD requires checking the yoke half assembly for any crack and replacing a cracked yoke assembly before further flight. This AD also requires replacing certain yokes with airworthy yokes before further flight
after January 1, 2001. This AD is prompted by the discovery of cracks in the yoke.
Comments?? Lu?
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To: hover Lover
As surprising as it might seem, I can't say Robinson messed up. The use of incorrect material is quite common in the aircraft industry. It shouldn't happen but it does.
I have to assume that the process engineers specified the material used to make the yokes and that they considered all of the environmental and stress related conditions in the selection of the material. What this seems to be, is a quality problem at the manufacturer of the yokes assuming it was a bought out spec part.
However, Robinson makes most of the pieceparts that go into the makeup of the 22 and 44. If it was in fact made by Robinson and assuming that the spec for the base metal was very tight, then they did screw up, as they made several mistakes in their material selection for that particular batch of parts and their quality control in allowing the use of non spec material. But, it happens everywhere. Sometimes it's a faulty process or faulty manufacturing.
As an illustration,when I worked in Iran, Bell Helicopter shipped 43 B-214s to our facility for assembly and checkout. Of the 43 helicopters, we found 18 that had improperly heat treated gears in the transmissions. Bell built the trannies and made the gears.
Sikorsky improperly overhauled two S-61 rotorheads and caused the crash of two LA Airways Helicopters with all passengers and crew lost including the grandson of the owner of the airline.
It happens but it shouldn't
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The Cat
As surprising as it might seem, I can't say Robinson messed up. The use of incorrect material is quite common in the aircraft industry. It shouldn't happen but it does.
I have to assume that the process engineers specified the material used to make the yokes and that they considered all of the environmental and stress related conditions in the selection of the material. What this seems to be, is a quality problem at the manufacturer of the yokes assuming it was a bought out spec part.
However, Robinson makes most of the pieceparts that go into the makeup of the 22 and 44. If it was in fact made by Robinson and assuming that the spec for the base metal was very tight, then they did screw up, as they made several mistakes in their material selection for that particular batch of parts and their quality control in allowing the use of non spec material. But, it happens everywhere. Sometimes it's a faulty process or faulty manufacturing.
As an illustration,when I worked in Iran, Bell Helicopter shipped 43 B-214s to our facility for assembly and checkout. Of the 43 helicopters, we found 18 that had improperly heat treated gears in the transmissions. Bell built the trannies and made the gears.
Sikorsky improperly overhauled two S-61 rotorheads and caused the crash of two LA Airways Helicopters with all passengers and crew lost including the grandson of the owner of the airline.
It happens but it shouldn't
------------------
The Cat
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All,
Lu's theory about the 18 degree offset is actualy correct.It makes sense when you look at his diagrams and when you look at the helicopter and carry out his proposed tests.
Next time you fly an R22 solo, pay particular attention to the cyclic position in cruise. I did and found that as Lu suggested, the cyclic was in fact slightly off center to the right.It was as I say however very slight and only noticable if you make a careful observation.
It is well recognised, and even Lu has grasped the concept of inflow roll/transverse flow. We all know that the effect of such is to roll the helo to the right. Similarly the effect of an offset lateral CofG (sitting on one side or another with no ballast)will tend to roll the helo if it is not counteracted. The solo seat in the R22 is the right one. This balances the fuel which is on the left of the fuselage(alpha model)and the main tank also on the left(beta)but in low fuel conditions, creates a lateral CofG condition to the right.
So, we have inflow roll and an out of balance CofG both trying to roll the helicopter to the right, yet we still need a little (very small amount)of right cyclic. (Anyone who does not believe this, do as I did and try it before you respond.)
If we sat on the left side and inflow roll did not exist, this would be more noticable.
When we have accepted this fact and we apply it to Lu's theory about adding a tad of left cyclic along with our aft cyclic in order to recover from a low "G" roll over, we see that in theory once again Lu is correct.
However,as we all know, the R22 is very responsive to cyclic imput and application of aft cyclic acts very quickly to restore positive "G" or reload the rotor disc.Hence recovery is very rapid. It was alluded to by Rotorque way back on page 1 I think, that the primary objective in a low "G" situation is to avoid mast bump. So even though you may be correct,Lu, by saying that a little left cyclic will aid recovery by alieviating the right roll, the problem is, how much? A heavey handed application will result in mast bump and almost certain death.
Reloading the rotor disc by applying aft cyclic whilst keeping it laterally nuetral, will ensure a safe recovery, albiet with a slight bank to the right, whereas a simultanious imput of left (or right) cyclic runs the risk of disaster.
It is a natural tendancy to oppose the direction of roll with cyclic. This is another reason why it is not wise to teach a (TAD)of left cyclic to aid recovery. 9 out of 10 pilots, particularly inexperienced ones will over control or use left cyclic as a primary means of recovery, which is what we are trying to avoid.
It may be of interest for most pilots, and Lu,to note that when flying a B47 (solo) that the cyclic (in cruise)is also displaced slightly to the right.Pilot flys from left seat.Similarly in a B206 flying from the right seat the cyclic is to the left. Try it.
I have said this before but I'll say it again.(Lu you have to accept this) Out of balance flight does not ALONE cause mast bump or main rotor failure.It is NOT a limitation.
It DOES make the helo less stable and CAN,when coupled with harsh control movements or a bunt over manouver, increase the likely hood of loss of control due to low"G" roll. It is therefore RECOMENDED, along with turbulence, abrupt control movements and bunt overs,to avoid out of balance flight. Simple as that!
I would be happy to demonstrate full pedal travel at .6 VNE to you Lu, although it is not something that anyone would do on a regular basis.
Mustering cattle, would argueably have to be the harshest environment that a working helicopter would have to endure.It is true that the absense of a drag brace puts a spinning load on the coneing hinge and that the bolt holes do elongate or out of round.(for lack of a technical term)Rotor heads working on mustering machines regularly survive 2000hrs. Re-bushing the cone bearing hole sees them returned to service.There has been absolutely no evidence of mast fatigue or failure.
Lu's theory about the 18 degree offset is actualy correct.It makes sense when you look at his diagrams and when you look at the helicopter and carry out his proposed tests.
Next time you fly an R22 solo, pay particular attention to the cyclic position in cruise. I did and found that as Lu suggested, the cyclic was in fact slightly off center to the right.It was as I say however very slight and only noticable if you make a careful observation.
It is well recognised, and even Lu has grasped the concept of inflow roll/transverse flow. We all know that the effect of such is to roll the helo to the right. Similarly the effect of an offset lateral CofG (sitting on one side or another with no ballast)will tend to roll the helo if it is not counteracted. The solo seat in the R22 is the right one. This balances the fuel which is on the left of the fuselage(alpha model)and the main tank also on the left(beta)but in low fuel conditions, creates a lateral CofG condition to the right.
So, we have inflow roll and an out of balance CofG both trying to roll the helicopter to the right, yet we still need a little (very small amount)of right cyclic. (Anyone who does not believe this, do as I did and try it before you respond.)
If we sat on the left side and inflow roll did not exist, this would be more noticable.
When we have accepted this fact and we apply it to Lu's theory about adding a tad of left cyclic along with our aft cyclic in order to recover from a low "G" roll over, we see that in theory once again Lu is correct.
However,as we all know, the R22 is very responsive to cyclic imput and application of aft cyclic acts very quickly to restore positive "G" or reload the rotor disc.Hence recovery is very rapid. It was alluded to by Rotorque way back on page 1 I think, that the primary objective in a low "G" situation is to avoid mast bump. So even though you may be correct,Lu, by saying that a little left cyclic will aid recovery by alieviating the right roll, the problem is, how much? A heavey handed application will result in mast bump and almost certain death.
Reloading the rotor disc by applying aft cyclic whilst keeping it laterally nuetral, will ensure a safe recovery, albiet with a slight bank to the right, whereas a simultanious imput of left (or right) cyclic runs the risk of disaster.
It is a natural tendancy to oppose the direction of roll with cyclic. This is another reason why it is not wise to teach a (TAD)of left cyclic to aid recovery. 9 out of 10 pilots, particularly inexperienced ones will over control or use left cyclic as a primary means of recovery, which is what we are trying to avoid.
It may be of interest for most pilots, and Lu,to note that when flying a B47 (solo) that the cyclic (in cruise)is also displaced slightly to the right.Pilot flys from left seat.Similarly in a B206 flying from the right seat the cyclic is to the left. Try it.
I have said this before but I'll say it again.(Lu you have to accept this) Out of balance flight does not ALONE cause mast bump or main rotor failure.It is NOT a limitation.
It DOES make the helo less stable and CAN,when coupled with harsh control movements or a bunt over manouver, increase the likely hood of loss of control due to low"G" roll. It is therefore RECOMENDED, along with turbulence, abrupt control movements and bunt overs,to avoid out of balance flight. Simple as that!
I would be happy to demonstrate full pedal travel at .6 VNE to you Lu, although it is not something that anyone would do on a regular basis.
Mustering cattle, would argueably have to be the harshest environment that a working helicopter would have to endure.It is true that the absense of a drag brace puts a spinning load on the coneing hinge and that the bolt holes do elongate or out of round.(for lack of a technical term)Rotor heads working on mustering machines regularly survive 2000hrs. Re-bushing the cone bearing hole sees them returned to service.There has been absolutely no evidence of mast fatigue or failure.
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To: Outside Loop
I would like to jump up and down saying I told you so but I won’t and, this is why. You stated that my comment about the cyclic being slightly off center to the right was correct. Even if there were no 18-degree offset the stick would still be right of center while flying forward as that is the lateral rigged neutral position.
Several posts above I suggested to Helo Teacher that he should perform a test to determine if my theory was correct. If in your demonstration the stick were right of the rigged neutral position then I would be correct. Until that test is performed, we really won’t know if I am correct.
Regarding out of balance flight causing mast bumping, I didn’t say that. The reference to out of balance flight causing mast bumping is in the Robinson POHs and that came from the AD that precipitated the entry in the POH.
My argument in my report was that if the flight maneuvers were restricted then if the helicopters were placed for certification at this time they would be rejected because they can’t comply with the certification requirements for Normal Category Rotorcraft.
Regarding the out-of-round coning journals, I did not see this as those journals had been removed from the two rotorheads that I observed at Geneva Aviation. It was the teeter journals that were worn egg shaped. It is not the turning inertial loads that cause it, as if they were, the journals would be worn in a different way. It was the attempt to lead and lag on a rotorhead that is stiff in plane. If the loads were sufficient to cause this wear on the journals the loads had to be reacted at the shaft which would cause a cyclic wind up and relaxation at 4 times the speed of rotation. If the shaft reacted the loads then the gear train reacted the shaft loads, which would cause a cyclic loading on the gears. Ultimately, the loads were reacted by the transmission supports into the fuselage. One thing that I have never addressed regarding the lead lag tendencies is that in order to have the cone and teeter journals eggshaped the loads must be generated by the blades which will bend spanwise +/- at the same cyclical rate.
Maybe I misspoke when I said it would cause fatigue of the shaft. We won’t know, unless they revisit some of the rotorhead loss accidents. There is one way to determine if the loads are sufficient to cause torsional bending of the shaft and that is to paint the shaft with Stress Coat
I don’t know if this material is available in OZ. It looks like white paint and when it cures it creates
a frangible hard film on the part that was painted. If any bending or torsional loads are reacted the film will crack and it can be determined in which direction the loads were applied.
Being able to demonstrate full pedal travel at, 6VNE proves that the helicopter is capable of doing the maneuver. My argument is that you are restricted from doing it by virtue of the Airworthiness Directive, which is AD 95-26-04. The UK CAA interpretation of this AD is much more stringent that that of Robinson and what they put in the POHs. Somewhere above, I provided a web site that has the letter. The web address is: http://205467.homestead.com/CAA.html
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The Cat
[This message has been edited by Lu Zuckerman (edited 28 November 2000).]
I would like to jump up and down saying I told you so but I won’t and, this is why. You stated that my comment about the cyclic being slightly off center to the right was correct. Even if there were no 18-degree offset the stick would still be right of center while flying forward as that is the lateral rigged neutral position.
Several posts above I suggested to Helo Teacher that he should perform a test to determine if my theory was correct. If in your demonstration the stick were right of the rigged neutral position then I would be correct. Until that test is performed, we really won’t know if I am correct.
Regarding out of balance flight causing mast bumping, I didn’t say that. The reference to out of balance flight causing mast bumping is in the Robinson POHs and that came from the AD that precipitated the entry in the POH.
My argument in my report was that if the flight maneuvers were restricted then if the helicopters were placed for certification at this time they would be rejected because they can’t comply with the certification requirements for Normal Category Rotorcraft.
Regarding the out-of-round coning journals, I did not see this as those journals had been removed from the two rotorheads that I observed at Geneva Aviation. It was the teeter journals that were worn egg shaped. It is not the turning inertial loads that cause it, as if they were, the journals would be worn in a different way. It was the attempt to lead and lag on a rotorhead that is stiff in plane. If the loads were sufficient to cause this wear on the journals the loads had to be reacted at the shaft which would cause a cyclic wind up and relaxation at 4 times the speed of rotation. If the shaft reacted the loads then the gear train reacted the shaft loads, which would cause a cyclic loading on the gears. Ultimately, the loads were reacted by the transmission supports into the fuselage. One thing that I have never addressed regarding the lead lag tendencies is that in order to have the cone and teeter journals eggshaped the loads must be generated by the blades which will bend spanwise +/- at the same cyclical rate.
Maybe I misspoke when I said it would cause fatigue of the shaft. We won’t know, unless they revisit some of the rotorhead loss accidents. There is one way to determine if the loads are sufficient to cause torsional bending of the shaft and that is to paint the shaft with Stress Coat
I don’t know if this material is available in OZ. It looks like white paint and when it cures it creates
a frangible hard film on the part that was painted. If any bending or torsional loads are reacted the film will crack and it can be determined in which direction the loads were applied.
Being able to demonstrate full pedal travel at, 6VNE proves that the helicopter is capable of doing the maneuver. My argument is that you are restricted from doing it by virtue of the Airworthiness Directive, which is AD 95-26-04. The UK CAA interpretation of this AD is much more stringent that that of Robinson and what they put in the POHs. Somewhere above, I provided a web site that has the letter. The web address is: http://205467.homestead.com/CAA.html
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The Cat
[This message has been edited by Lu Zuckerman (edited 28 November 2000).]
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to arm the floats: I had mentioned earlier either a mast or disk rigging would counter translating tendency- to clarify, if the cyclic, while in a centered position, places the rotor disk in a slight left position, the
disk has been "rigged".
To Lu, you mentioned that while the swashplate is flat the cyclic is slightly right of center- so if you were to move it the cyclic to the center then you have a disk that moves slightly left, right?
It was my opinion (and I may have come to this conclusion on my own) that the right trim knob in the r22 compensated for this "rigging" but now that I've thought about it I'd like to pose Lu's earlier question once more: what's the knob for? Does someone have
a definitive answer? (Frank, if your list isn't too long already)
disk has been "rigged".
To Lu, you mentioned that while the swashplate is flat the cyclic is slightly right of center- so if you were to move it the cyclic to the center then you have a disk that moves slightly left, right?
It was my opinion (and I may have come to this conclusion on my own) that the right trim knob in the r22 compensated for this "rigging" but now that I've thought about it I'd like to pose Lu's earlier question once more: what's the knob for? Does someone have
a definitive answer? (Frank, if your list isn't too long already)
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To: Imlanphere
Youre comment to Arm the Floats is correct. When the cyclic is in the mid point of its's travel (Fore and aft and left and right the swashplate is tipped to the left. However, when the cyclic is in the rigged neutral position the swashplate is flat.
Your second point is correct as well as it states the same point made above.
Regarding the Cyclic lateral knob here is the definition taken from the repair manual.
The function of the cyclic lateral trim spring is to remove the left stick force in cruise conditions. It is actuated by pulling up on the black knob located forward of the cyclic stick.
When you pull up on the black knob (and not the mixture control) it misaligns a spring pack that is attached to the A177-1 pivot assembly. So far so good. In order to cause the misalignment one end of the shaft that the spring rides on must go up and the other must go down. However from what I can gather from the illustrations in the maintenance manual the other end is anchored to the left keel beam. At that point I have to give up as I can't figure out how they can alter the spring force in order to counter the loads that cause the stick to move.
Maybe, some really sharp mechanic can explain how the moving of the knob in an upward direction effects the spring load.
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The Cat
[This message has been edited by Lu Zuckerman (edited 28 November 2000).]
Youre comment to Arm the Floats is correct. When the cyclic is in the mid point of its's travel (Fore and aft and left and right the swashplate is tipped to the left. However, when the cyclic is in the rigged neutral position the swashplate is flat.
Your second point is correct as well as it states the same point made above.
Regarding the Cyclic lateral knob here is the definition taken from the repair manual.
The function of the cyclic lateral trim spring is to remove the left stick force in cruise conditions. It is actuated by pulling up on the black knob located forward of the cyclic stick.
When you pull up on the black knob (and not the mixture control) it misaligns a spring pack that is attached to the A177-1 pivot assembly. So far so good. In order to cause the misalignment one end of the shaft that the spring rides on must go up and the other must go down. However from what I can gather from the illustrations in the maintenance manual the other end is anchored to the left keel beam. At that point I have to give up as I can't figure out how they can alter the spring force in order to counter the loads that cause the stick to move.
Maybe, some really sharp mechanic can explain how the moving of the knob in an upward direction effects the spring load.
------------------
The Cat
[This message has been edited by Lu Zuckerman (edited 28 November 2000).]
Guest
Posts: n/a
R22 Trim, (forward flight):
The cyclically varying pitch (necessary at speed to prevent a changing disc attitude called 'flap back' which would result from 'flapping to equality' if the 'flapping to equality' was actually required to eliminate 'dissimetry of lift') has max rate of pitch increase at the front (max decrease at the back) so the pitch link needs to be pushed up on the port side, the pilot does this by applying a small force to the right - or you can get the elastic band to do it for you by pulling the 'trim' knob up!
Nice to see a few people have been putting up a valiant (but feeble) fight against the distortions of the 'well intentioned' Lu!
(Hope you can follow that Lu!)
The cyclically varying pitch (necessary at speed to prevent a changing disc attitude called 'flap back' which would result from 'flapping to equality' if the 'flapping to equality' was actually required to eliminate 'dissimetry of lift') has max rate of pitch increase at the front (max decrease at the back) so the pitch link needs to be pushed up on the port side, the pilot does this by applying a small force to the right - or you can get the elastic band to do it for you by pulling the 'trim' knob up!
Nice to see a few people have been putting up a valiant (but feeble) fight against the distortions of the 'well intentioned' Lu!
(Hope you can follow that Lu!)
Guest
Posts: n/a
(and Lu: pulling up the non anchored end of the spring assembly basically gives it an 'Arm' in the lateral direction, whereas in the lower position it has no 'Arm' therefore no effect. Stop 'scaring the children' - learn to fly you might like it!)
Guest
Posts: n/a
Not to mention the spring loaded swashplate on the 212 for the double hydraulic failure case (forward right quadrant).
As far as I know the pilot always compensates for tail rotor drift with cyclic, hence the skid low hovers, there is no mast imput in the lateral sense.
The advancing blade does flap up, it is 'prevented' from doing so though by further forward cyclic, hence the diference in the tip plane plane and the swash plate plane.
(Tiger induced typing errors!)
------------------
Another day in paradise
[This message has been edited by 212man (edited 28 November 2000).]
As far as I know the pilot always compensates for tail rotor drift with cyclic, hence the skid low hovers, there is no mast imput in the lateral sense.
The advancing blade does flap up, it is 'prevented' from doing so though by further forward cyclic, hence the diference in the tip plane plane and the swash plate plane.
(Tiger induced typing errors!)
------------------
Another day in paradise
[This message has been edited by 212man (edited 28 November 2000).]
Guest
Posts: n/a
Yup, that is basically correct. It is that forward cyclic which runs less pitch on the high airspeed side and more pitch on the low airspeed side (like magic - just where you need it) so the max rate of change of pitch is at the front (and back).
And yes one way or the other the disc will always have to make the equal and opposite force of the tail rotor - whether that results in 'tilting' or not depends on other stuff (height of tail rotor, CoG etc)
Off now, byeee...
And yes one way or the other the disc will always have to make the equal and opposite force of the tail rotor - whether that results in 'tilting' or not depends on other stuff (height of tail rotor, CoG etc)
Off now, byeee...
Guest
Posts: n/a
To: Joe Pilot (Post 1)
The tendency to "flap back" is compensated for by the individual blade flapping up and the delta hinge effect on the pitchlink takes pitch out of the blade compensating for the increased lift on the advancing side.
This is very true if you are flying an autogyro and not a helicopter. The entire theory of flapping up of the advancing blade is based on autogyro aerodynamics. What causes flapback is the increased lift on the advancing side of the blade causing a lift differential across the disc and gyroscopic precession causes the so called flap back. It is a very mild case of retreating blade stall. Only in this case the retreating blade is not in the stall range it is just generating less lift. The pilot counters this condition by restoring the position of the disc by pushing forward cyclic or, if the swash plate remains in the original position and the pilot does not correct, the delta hinge effect will pull pitch out of the blade on one side and increase the pitch on the other side and the gyroscopic precession (if I worked this out in my head correctly) will cause the helicopter to roll left.
Try to picture this. The pilot pushes forward cyclic, the swash plate tips in the required direction. The advancing blade is a part of a rotating disc and as such has the characteristics of a gyroscope. When the pilot pushes forward cyclic the disc due to precession will tip down over the nose and the other side of the disc will rise over the tail. To use the term flapping the forward part of the disc has flapped down and the rear part of the disc has flapped up. Now, the aerodynamicists tell you that due to the relative wind the advancing blade flaps up and the retreating blade flaps down. In a scenario like that, the helicopter would be flying backwards.
Using my description, the disc flaps up over the nose and down over the tail but when it starts the pilot corrects for the condition by pushing forward cyclic. The flapping is minimal but, if you read the text books you would be lead to believe that the flapping is extensive.
Once again they have taken a movie film that shows the entire process and have selected one of thousands of frames and tell you that this is what is happening.
In your first post you indicated that pulling the knob up will cause the elastic cords to increase the right force. The elastic bands are on the F&A cyclic. This was corrected in your second post.
To: Joe Pilot (post 2)
You stated that pulling up on the non anchored end of the spring assembly basically gives it an "arm" in the lateral direction, whereas in the lower position it has no "arm" therefore ,no effect.
The operative word(s) are non anchored end. Form that you can assume that there is an anchored end. From the pictures in the maintenance manual it is difficult to see how the end attached to the knob can move upward if the other end is anchored. The shaft that is attached to the knob is a first class lever which pivots in a bearing that allows shaft movement. I believe what you said about applyinf a force or removing a force but, my question is how it does it if one end of the first class lever arm is capable of beinfg displaced upward when the opposite end of the shaft is anchored. That is why I asked if some sharp mechanic could explain how it works.
NOTE: DISREGARD MY COMMENTS ABOUT THE RIGHT TRIM ASSEMBLY. IN LOOKING AT THE PICTURES IN THE MM I CAN NOW SEE THAT IT IS NOT A FIRST CLASS LEVER. IT IS A THIRD CLASS LEVER. WHEN THE PILOT PULLS UP ON THE KNOB IT RAISES THE A 177 PIVOT, WHICH PIVOTS AT THE A 176-1 YOKE. THIS RAISES THE CYCLIC STICK. THIS ALSO CHANGES THE ANGULAR RELATIONSHIP BETWEEN THE A581-1 ARM AND THE SPRING PACK SO THAT WHEN THE PILOT MOVES THE STICK TO THE LEFT IT COMPRESSES THE SPRING AND PROVIDES A RESISTANCE. WHEN HE MOVES THE CYCLIC TO THE RIGHT THE SPRING RELAXES THUS REDUCING THE RESISTANCE.
NOW, WE GET BACK TO THE EXPLANATION PROVIDED IN THE MM ABOUT THE PURPOSE OF THE RIGHT TRIM ASSEMBLY. IT STATES THAT IT REMOVES THE LEFT STICK FORCES IN CRUISE BUT, IF I GUESSED RIGHT ABOUT HOW THE UNIT WORKS, THE SPRING INCREASES THE LEFT STICK FORCE THAT THE PILOT MUST OVERCOME TO DISPLACE THE STICK TO THE LEFT. AM I RIGHT OR WRONG?
To:212man
Not all helicopters require compensating cyclic to overcome lateral drift caused by the propeller effect. Many Sikorsky helicopters, at least those that I am most familiar with have this built into the mixing unit. Sikorsky also tilts their transmissions forward by three degrees (again those that I am familiar with). That is why a Sikorsky hangs down at the tail and leans to the left. If I remember correctly they land left, tail right. Or, maybe tail, left and then right.
Regarding blade flap please see above.
------------------
The Cat
[This message has been edited by Lu Zuckerman (edited 29 November 2000).]
The tendency to "flap back" is compensated for by the individual blade flapping up and the delta hinge effect on the pitchlink takes pitch out of the blade compensating for the increased lift on the advancing side.
This is very true if you are flying an autogyro and not a helicopter. The entire theory of flapping up of the advancing blade is based on autogyro aerodynamics. What causes flapback is the increased lift on the advancing side of the blade causing a lift differential across the disc and gyroscopic precession causes the so called flap back. It is a very mild case of retreating blade stall. Only in this case the retreating blade is not in the stall range it is just generating less lift. The pilot counters this condition by restoring the position of the disc by pushing forward cyclic or, if the swash plate remains in the original position and the pilot does not correct, the delta hinge effect will pull pitch out of the blade on one side and increase the pitch on the other side and the gyroscopic precession (if I worked this out in my head correctly) will cause the helicopter to roll left.
Try to picture this. The pilot pushes forward cyclic, the swash plate tips in the required direction. The advancing blade is a part of a rotating disc and as such has the characteristics of a gyroscope. When the pilot pushes forward cyclic the disc due to precession will tip down over the nose and the other side of the disc will rise over the tail. To use the term flapping the forward part of the disc has flapped down and the rear part of the disc has flapped up. Now, the aerodynamicists tell you that due to the relative wind the advancing blade flaps up and the retreating blade flaps down. In a scenario like that, the helicopter would be flying backwards.
Using my description, the disc flaps up over the nose and down over the tail but when it starts the pilot corrects for the condition by pushing forward cyclic. The flapping is minimal but, if you read the text books you would be lead to believe that the flapping is extensive.
Once again they have taken a movie film that shows the entire process and have selected one of thousands of frames and tell you that this is what is happening.
In your first post you indicated that pulling the knob up will cause the elastic cords to increase the right force. The elastic bands are on the F&A cyclic. This was corrected in your second post.
To: Joe Pilot (post 2)
You stated that pulling up on the non anchored end of the spring assembly basically gives it an "arm" in the lateral direction, whereas in the lower position it has no "arm" therefore ,no effect.
The operative word(s) are non anchored end. Form that you can assume that there is an anchored end. From the pictures in the maintenance manual it is difficult to see how the end attached to the knob can move upward if the other end is anchored. The shaft that is attached to the knob is a first class lever which pivots in a bearing that allows shaft movement. I believe what you said about applyinf a force or removing a force but, my question is how it does it if one end of the first class lever arm is capable of beinfg displaced upward when the opposite end of the shaft is anchored. That is why I asked if some sharp mechanic could explain how it works.
NOTE: DISREGARD MY COMMENTS ABOUT THE RIGHT TRIM ASSEMBLY. IN LOOKING AT THE PICTURES IN THE MM I CAN NOW SEE THAT IT IS NOT A FIRST CLASS LEVER. IT IS A THIRD CLASS LEVER. WHEN THE PILOT PULLS UP ON THE KNOB IT RAISES THE A 177 PIVOT, WHICH PIVOTS AT THE A 176-1 YOKE. THIS RAISES THE CYCLIC STICK. THIS ALSO CHANGES THE ANGULAR RELATIONSHIP BETWEEN THE A581-1 ARM AND THE SPRING PACK SO THAT WHEN THE PILOT MOVES THE STICK TO THE LEFT IT COMPRESSES THE SPRING AND PROVIDES A RESISTANCE. WHEN HE MOVES THE CYCLIC TO THE RIGHT THE SPRING RELAXES THUS REDUCING THE RESISTANCE.
NOW, WE GET BACK TO THE EXPLANATION PROVIDED IN THE MM ABOUT THE PURPOSE OF THE RIGHT TRIM ASSEMBLY. IT STATES THAT IT REMOVES THE LEFT STICK FORCES IN CRUISE BUT, IF I GUESSED RIGHT ABOUT HOW THE UNIT WORKS, THE SPRING INCREASES THE LEFT STICK FORCE THAT THE PILOT MUST OVERCOME TO DISPLACE THE STICK TO THE LEFT. AM I RIGHT OR WRONG?
To:212man
Not all helicopters require compensating cyclic to overcome lateral drift caused by the propeller effect. Many Sikorsky helicopters, at least those that I am most familiar with have this built into the mixing unit. Sikorsky also tilts their transmissions forward by three degrees (again those that I am familiar with). That is why a Sikorsky hangs down at the tail and leans to the left. If I remember correctly they land left, tail right. Or, maybe tail, left and then right.
Regarding blade flap please see above.
------------------
The Cat
[This message has been edited by Lu Zuckerman (edited 29 November 2000).]
Guest
Posts: n/a
Hi Lu
thanks for the report; it has been distributed to potential students to give them a clue. also, the fact that 3 have fallen out of the sky (...and NOT pilot error according to inv rpt.) in our area/(region), have not made a favorable impression. One, (of many) DE whom I know also told FAA he refuses to give checkrides in them anymore (was told he could use his 'discretion') this time, as a 500 hr (seemed like a new one, but I guess for a robby, that's beyond it's time limit!) anyway, the r22 was being rolled out of the hangar, and as it bumped over the INGROUND tracks for the hangar doors, the tailboom fell off! When the operator called the robby factory, their reply was , and is QUOTED " Oh, no problem, happens all the time. The fix is simple." HA! seems like a problem in the air if it happens! the 'fix' cost about $47.00 USD.
There is a pub out (avail in US) that compiles all of the Robby accidents and classifies the pilot error vs mechanical failures accidents. What I want to know is WHY do these robby jockeys accept the accidents/incidents that are pilot error, but conveniently ignore the Other Chart that compares the robby to Hiller, Bell47, Enstroms, Schweitzer, JetRanger, etc. (just to mention a few of the other training machines), Accidents, classified as LOC (loss of control) than was NOT in any way shape or form due to PILOT ERROR, nor contact with any object/terrain, but Specifically a MECHANICAL MALFUNCTION per 100,000 flight hrs. ???
This is all nicely arranged on this chart; and in conclusion, the robby is 100 times more likely to have mechanical failure than the JetRanger (which has the best record per 100,000 flt hrs regarding NON-pilot error, Mechanical Malfunction/Failure).
Also is this pub, are DETAILED reports of Each of these robby accidents that were declared mechanical malfunctions...and not the pilot error accidents.
It is Beyond me that there are people who think this flying toilet is anything comparable to a real helicopter! It even gives 'tinkertoy' a bad name (as it is a joke in the gulf offshore env).
Why are they denying these facts???
Lu, do you have a copy of this pub? It is worth the report and helps get the truth distributed to the pilot-wannabe world. We just had another robby co belly-up in the region due to poor publicity once the facts were finally learned by the public. It's time more give in and get with the program.
There are plenty of other great training machines that are less expensive than the turbines.
-seisfly
thanks for the report; it has been distributed to potential students to give them a clue. also, the fact that 3 have fallen out of the sky (...and NOT pilot error according to inv rpt.) in our area/(region), have not made a favorable impression. One, (of many) DE whom I know also told FAA he refuses to give checkrides in them anymore (was told he could use his 'discretion') this time, as a 500 hr (seemed like a new one, but I guess for a robby, that's beyond it's time limit!) anyway, the r22 was being rolled out of the hangar, and as it bumped over the INGROUND tracks for the hangar doors, the tailboom fell off! When the operator called the robby factory, their reply was , and is QUOTED " Oh, no problem, happens all the time. The fix is simple." HA! seems like a problem in the air if it happens! the 'fix' cost about $47.00 USD.
There is a pub out (avail in US) that compiles all of the Robby accidents and classifies the pilot error vs mechanical failures accidents. What I want to know is WHY do these robby jockeys accept the accidents/incidents that are pilot error, but conveniently ignore the Other Chart that compares the robby to Hiller, Bell47, Enstroms, Schweitzer, JetRanger, etc. (just to mention a few of the other training machines), Accidents, classified as LOC (loss of control) than was NOT in any way shape or form due to PILOT ERROR, nor contact with any object/terrain, but Specifically a MECHANICAL MALFUNCTION per 100,000 flight hrs. ???
This is all nicely arranged on this chart; and in conclusion, the robby is 100 times more likely to have mechanical failure than the JetRanger (which has the best record per 100,000 flt hrs regarding NON-pilot error, Mechanical Malfunction/Failure).
Also is this pub, are DETAILED reports of Each of these robby accidents that were declared mechanical malfunctions...and not the pilot error accidents.
It is Beyond me that there are people who think this flying toilet is anything comparable to a real helicopter! It even gives 'tinkertoy' a bad name (as it is a joke in the gulf offshore env).
Why are they denying these facts???
Lu, do you have a copy of this pub? It is worth the report and helps get the truth distributed to the pilot-wannabe world. We just had another robby co belly-up in the region due to poor publicity once the facts were finally learned by the public. It's time more give in and get with the program.
There are plenty of other great training machines that are less expensive than the turbines.
-seisfly
Guest
Posts: n/a
To: Seismicpilot
I sent this to a guy in Argentina. He lost a friend in the crash of an R44 several months ago.
Contact the NTSB in Washington, DC using the following address.
National Transportation Safety Board
490 L'Enfant Plaza,S. W.
Washington DC
20594-2000
Aviation Accident Data Specialist Analysis and Data Division
Attn: Ms. Latricia Carter RE-50 THIS INFORMATION DATES BACK TO 1996. She may be gone but the function is still there.
Telephone No. 202 382 6522
Fax No. 202 385 6008 THIS WILL BE THE FASTEST WAY
Ask for a complete printout of all accidents involving R22 and R44 Helicopters.
Also, ask how you can obtain a copy of this report. Special Investigation Report
Robinson Helicopter Company R22 Loss of Main Rotor control accidents.
Report No. PB96 -917003 NTSB/SIR-96/03
Between the printout and the report you will have everything you need. The print out does not have the registration numbers of the helicopter but it does Identify the location of the crash. The report just deals with rotor loss accidents but it does have the registration numbers.
He asked me how I got involved with the Robinson problems. This is what I told him
As far as my interest in this it stems from my love of helicopters. I first started working on them in 1949 while in the US Coast Guard. I have been involved with helicopters for the better part of 45 years. I work as an Engineering Consultant in the capacity of an Reliability, Maintainability and Systems Safety Engineer. I became interested in the Robinson problems in 1994 and the report is the culmination of that involvement.
Another thing that you can do is go on the internet on the NTSB site. They have all helicopter accidents listed. It contains the Robinson helicopter accidents but you have to look for them.
If you want to see the safety record from the perspective of Robinson log on to:
http://www.hfi.ca/mech/r22_accident_analysis.html
I posted this on page 6 of this thread. You may have not seen it.
Conflict of interest alleged in FAA crash investigations
By MARINA MALIKOFF
Sentinel staff writer
Of the dozens of R-22 accident investigations involving main rotor loss reviewed by the Sentinel, the National Transportation Safety Board frequently listed the probable cause as "undetermined" or pilot error — findings that do not surprise Palo Alto lawyer Michael Danko.
Because pilots and victims’ families are excluded from the investigation process, fault often is placed with the pilot, he said.
"Unfortunately, when there is a crash such as this and the NTSB wants to examine whether the aircraft is defective ... they call on all the manufacturers," said Danko, who is also a pilot. "They’ll ask Robinson if it is defective. To me, that is like asking the fox to find out what happened to the chickens."
Danko, whose firm is investigating a fatal August 1999 R-22 crash in Ireland nearly identical to the Watsonville crash in August, said the NTSB will "essentially staple their report to the technical report from Robinson, which will always point to pilot error."
NTSB accident investigations are conducted by what is known as the "party system," a process where the NTSB allows interested stakeholders, such as aircraft manufacturers and the Federal Aviation Administration, to join their crash probes. Anyone in a litigation position is excluded from the investigation.
The NTSB party system was the target of a 1999 study by the RAND Corp., a nonprofit public policy think tank. A RAND panel found significant potential for conflicts of interest when manufacturers are asked to police themselves.
The study, which was commissioned by the NTSB, recommended independent analytical and engineering resources assist in investigations "if (the NTSB) is to ensure its future independence and integrity," according to a statement issued by RAND when its report was released in December 1999.
The report was recently forwarded to the NTSB, where it is under management review, said NTSB spokeswoman Lauren Peduzzi. Recommendations and changes to the system will be considered, she said.
"The board’s mission is to investigate accidents, determine relevant safety issues and issue recommendations for improvements in order to prevent similar accidents from happening again," Peduzzi said. "Although the party process allows us to tap the manufacturer’s expertise with their equipment, the board’s investigators act as impartial leaders. ... It is their job to ensure that a fair and thorough investigation is conducted and that the probable cause accurately reflects the safety issues in the case."
Benjamin F. Venti, the father of a pilot who, along with two passengers, was killed in a Robinson R-44 crash in July 1993, was so troubled by the investigation into his son’s death, he appealed to his Los Angeles County congressman, Matthew Martinez.
Martinez contacted NTSB chairman Jim Hall, who appointed Venti an official member of the investigation team, contrary to NTSB policy.
Frank Robinson, president of Robinson Helicopter Co., said he and three others from his company had been on the team.
Evidence presented by Venti led the NTSB to revise its findings to show probable cause of the crash was a fatigue failure of the control stick assembly.
The report also found that lack of FAA oversight during the R-44 certification process may have contributed to the fatal crash.
The NTSB’s initial investigation had been hampered by a post-crash fire, which obscured evidence.
The RAND study also found that the 400-member NTSB staff simply doesn’t have the resources to thoroughly investigate each accident.
Jerry Sterns, whose Oakland-based firm specializes in aviation cases, agrees.
"The board does not have the budget nor the experts to do its job properly, so it is forced to rely heavily on outside people, who of course are supplied by the very companies being investigated," he said. "The companies many times drive the investigation, and the board has consistently refused to allow any representatives of the victims to participate and treats their lawyers as subversives."
However, Robinson, founder of the helicopter company, stressed that the NTSB investigator has full control over the crash probe, and that it would be impossible to conduct a thorough investigation without the manufacturer’s expertise.
"The manufacturer is not a theorist and is not allowed to touch anything at the site unless under the direction of the (NTSB) investigator," Robinson said. "He is there to identify the parts and has absolutely no input on probable cause."
In 1994, though, the NTSB learned that Robinson was serving as the quality assurance liaison to the FAA, raising concern of a conflict of interest during safety reviews.
Robinson confirmed he had served in that capacity — called the designated engineering representative — at various times over the years, and said it was "standard practice" in the industry for company officers to do so.
Robinson said he voluntarily resigned from that role four or five years ago. He now has three employees assigned to the job, one of whom is a company officer.
But accident investigations are still tainted by the cozy relationships that develop between FAA representatives and the manufacturers, according to several aviation law attorneys, who note that juries frequently reach conclusions about accident causes that are different than what the official investigators determine.
"In more than 50 percent of our cases, we have a cause that is different than the NTSB," said Richard Schaden, an attorney and aeronautical engineer. "The NTSB’s probable cause is heavily loaded on the pilot-error side."
When it comes to Robinson helicopters, that’s an appropriate finding, Robinson said.
"The fact remains that the vast majority of accidents do result from pilot error," Robinson said. "When they are used in training and by low (flying) time private pilots, it’s very high."
Those statistics don’t comfort families who have lost loved ones in Robinson crashes, said Danko, who maintains that a design flaw in the sensitive R-22 controls prevents flight instructors from responding quickly enough to prevent the crashes.
"History has shown the R-22 is not safe, and the fact is you have many high time pilots who have suffered the same scenario," Danko said. "You can’t blame all these accidents on pilots."
Aptos pilot Kent Reinhard and his student Gary Sefton died Aug. 18 when the rotor blades tore through the cockpit of Reinhard’s copter in midair during an instructional flight near Watsonville.
Reinhard, 57, had flown airplanes and helicopters for decades. He earned his first pilot’s license in 1961, and had logged thousands of flight hours — including 1,000 hours in the R-22 — at the time of his death.
In May 1996, Reinhard completed the Robinson Helicopter safety course and received an "average" rating — the most common rating, according to Robinson, who considers Reinhard a "high time" pilot.
Reinhard, a corporate pilot for Dole Food Co., operated a flight school out of the Watsonville Airport and was an R-22 stunt pilot with Showcopters, a Salinas-based air show team.
Sefton, 46, of Hollister, was studying for his airplane pilot’s license when he changed his focus to helicopters a year ago. The fatal flight with Reinhard was his first lesson.
Investigators from the NTSB, FAA and Robinson Helicopter Co. were at the crash scene the following day, along with local Sheriff’s Office inspectors.
The cause of the accident is still under investigation. The preliminary findings indicate loss of main rotor control is a factor, along with mast bumping, which is typically caused by abrupt input into the controls.
Reinhard’s sister, Jean Grace of Carmel, said Robinson’s position that pilot error likely caused the crash is predictable, but added that she is reserving judgment until the NTSB finalizes its report.
"From a liability standpoint, what else can (Robinson) say," Grace said. "At this point, we consider this a tragic accident."
Contact Marina Malikoff at [email protected].
------------------
The Cat
[This message has been edited by Lu Zuckerman (edited 29 November 2000).]
I sent this to a guy in Argentina. He lost a friend in the crash of an R44 several months ago.
Contact the NTSB in Washington, DC using the following address.
National Transportation Safety Board
490 L'Enfant Plaza,S. W.
Washington DC
20594-2000
Aviation Accident Data Specialist Analysis and Data Division
Attn: Ms. Latricia Carter RE-50 THIS INFORMATION DATES BACK TO 1996. She may be gone but the function is still there.
Telephone No. 202 382 6522
Fax No. 202 385 6008 THIS WILL BE THE FASTEST WAY
Ask for a complete printout of all accidents involving R22 and R44 Helicopters.
Also, ask how you can obtain a copy of this report. Special Investigation Report
Robinson Helicopter Company R22 Loss of Main Rotor control accidents.
Report No. PB96 -917003 NTSB/SIR-96/03
Between the printout and the report you will have everything you need. The print out does not have the registration numbers of the helicopter but it does Identify the location of the crash. The report just deals with rotor loss accidents but it does have the registration numbers.
He asked me how I got involved with the Robinson problems. This is what I told him
As far as my interest in this it stems from my love of helicopters. I first started working on them in 1949 while in the US Coast Guard. I have been involved with helicopters for the better part of 45 years. I work as an Engineering Consultant in the capacity of an Reliability, Maintainability and Systems Safety Engineer. I became interested in the Robinson problems in 1994 and the report is the culmination of that involvement.
Another thing that you can do is go on the internet on the NTSB site. They have all helicopter accidents listed. It contains the Robinson helicopter accidents but you have to look for them.
If you want to see the safety record from the perspective of Robinson log on to:
http://www.hfi.ca/mech/r22_accident_analysis.html
I posted this on page 6 of this thread. You may have not seen it.
Conflict of interest alleged in FAA crash investigations
By MARINA MALIKOFF
Sentinel staff writer
Of the dozens of R-22 accident investigations involving main rotor loss reviewed by the Sentinel, the National Transportation Safety Board frequently listed the probable cause as "undetermined" or pilot error — findings that do not surprise Palo Alto lawyer Michael Danko.
Because pilots and victims’ families are excluded from the investigation process, fault often is placed with the pilot, he said.
"Unfortunately, when there is a crash such as this and the NTSB wants to examine whether the aircraft is defective ... they call on all the manufacturers," said Danko, who is also a pilot. "They’ll ask Robinson if it is defective. To me, that is like asking the fox to find out what happened to the chickens."
Danko, whose firm is investigating a fatal August 1999 R-22 crash in Ireland nearly identical to the Watsonville crash in August, said the NTSB will "essentially staple their report to the technical report from Robinson, which will always point to pilot error."
NTSB accident investigations are conducted by what is known as the "party system," a process where the NTSB allows interested stakeholders, such as aircraft manufacturers and the Federal Aviation Administration, to join their crash probes. Anyone in a litigation position is excluded from the investigation.
The NTSB party system was the target of a 1999 study by the RAND Corp., a nonprofit public policy think tank. A RAND panel found significant potential for conflicts of interest when manufacturers are asked to police themselves.
The study, which was commissioned by the NTSB, recommended independent analytical and engineering resources assist in investigations "if (the NTSB) is to ensure its future independence and integrity," according to a statement issued by RAND when its report was released in December 1999.
The report was recently forwarded to the NTSB, where it is under management review, said NTSB spokeswoman Lauren Peduzzi. Recommendations and changes to the system will be considered, she said.
"The board’s mission is to investigate accidents, determine relevant safety issues and issue recommendations for improvements in order to prevent similar accidents from happening again," Peduzzi said. "Although the party process allows us to tap the manufacturer’s expertise with their equipment, the board’s investigators act as impartial leaders. ... It is their job to ensure that a fair and thorough investigation is conducted and that the probable cause accurately reflects the safety issues in the case."
Benjamin F. Venti, the father of a pilot who, along with two passengers, was killed in a Robinson R-44 crash in July 1993, was so troubled by the investigation into his son’s death, he appealed to his Los Angeles County congressman, Matthew Martinez.
Martinez contacted NTSB chairman Jim Hall, who appointed Venti an official member of the investigation team, contrary to NTSB policy.
Frank Robinson, president of Robinson Helicopter Co., said he and three others from his company had been on the team.
Evidence presented by Venti led the NTSB to revise its findings to show probable cause of the crash was a fatigue failure of the control stick assembly.
The report also found that lack of FAA oversight during the R-44 certification process may have contributed to the fatal crash.
The NTSB’s initial investigation had been hampered by a post-crash fire, which obscured evidence.
The RAND study also found that the 400-member NTSB staff simply doesn’t have the resources to thoroughly investigate each accident.
Jerry Sterns, whose Oakland-based firm specializes in aviation cases, agrees.
"The board does not have the budget nor the experts to do its job properly, so it is forced to rely heavily on outside people, who of course are supplied by the very companies being investigated," he said. "The companies many times drive the investigation, and the board has consistently refused to allow any representatives of the victims to participate and treats their lawyers as subversives."
However, Robinson, founder of the helicopter company, stressed that the NTSB investigator has full control over the crash probe, and that it would be impossible to conduct a thorough investigation without the manufacturer’s expertise.
"The manufacturer is not a theorist and is not allowed to touch anything at the site unless under the direction of the (NTSB) investigator," Robinson said. "He is there to identify the parts and has absolutely no input on probable cause."
In 1994, though, the NTSB learned that Robinson was serving as the quality assurance liaison to the FAA, raising concern of a conflict of interest during safety reviews.
Robinson confirmed he had served in that capacity — called the designated engineering representative — at various times over the years, and said it was "standard practice" in the industry for company officers to do so.
Robinson said he voluntarily resigned from that role four or five years ago. He now has three employees assigned to the job, one of whom is a company officer.
But accident investigations are still tainted by the cozy relationships that develop between FAA representatives and the manufacturers, according to several aviation law attorneys, who note that juries frequently reach conclusions about accident causes that are different than what the official investigators determine.
"In more than 50 percent of our cases, we have a cause that is different than the NTSB," said Richard Schaden, an attorney and aeronautical engineer. "The NTSB’s probable cause is heavily loaded on the pilot-error side."
When it comes to Robinson helicopters, that’s an appropriate finding, Robinson said.
"The fact remains that the vast majority of accidents do result from pilot error," Robinson said. "When they are used in training and by low (flying) time private pilots, it’s very high."
Those statistics don’t comfort families who have lost loved ones in Robinson crashes, said Danko, who maintains that a design flaw in the sensitive R-22 controls prevents flight instructors from responding quickly enough to prevent the crashes.
"History has shown the R-22 is not safe, and the fact is you have many high time pilots who have suffered the same scenario," Danko said. "You can’t blame all these accidents on pilots."
Aptos pilot Kent Reinhard and his student Gary Sefton died Aug. 18 when the rotor blades tore through the cockpit of Reinhard’s copter in midair during an instructional flight near Watsonville.
Reinhard, 57, had flown airplanes and helicopters for decades. He earned his first pilot’s license in 1961, and had logged thousands of flight hours — including 1,000 hours in the R-22 — at the time of his death.
In May 1996, Reinhard completed the Robinson Helicopter safety course and received an "average" rating — the most common rating, according to Robinson, who considers Reinhard a "high time" pilot.
Reinhard, a corporate pilot for Dole Food Co., operated a flight school out of the Watsonville Airport and was an R-22 stunt pilot with Showcopters, a Salinas-based air show team.
Sefton, 46, of Hollister, was studying for his airplane pilot’s license when he changed his focus to helicopters a year ago. The fatal flight with Reinhard was his first lesson.
Investigators from the NTSB, FAA and Robinson Helicopter Co. were at the crash scene the following day, along with local Sheriff’s Office inspectors.
The cause of the accident is still under investigation. The preliminary findings indicate loss of main rotor control is a factor, along with mast bumping, which is typically caused by abrupt input into the controls.
Reinhard’s sister, Jean Grace of Carmel, said Robinson’s position that pilot error likely caused the crash is predictable, but added that she is reserving judgment until the NTSB finalizes its report.
"From a liability standpoint, what else can (Robinson) say," Grace said. "At this point, we consider this a tragic accident."
Contact Marina Malikoff at [email protected].
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The Cat
[This message has been edited by Lu Zuckerman (edited 29 November 2000).]
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Thanks Lu for the indepth probe!
The pub to which I was referring is available at (some) aviation supply shops...and I am quite sure that it is a matter of discretion. Robbys are not that popular here, so info regarding them is readily available.
The NTSB link to their accident database is an excellent and very useful site! I have used that many times when aircraft shopping (f/w and helis)
My only question regarding the robbys and their proclaimed 'reliability and safety';
if these pilots and wannabes are so intent on defending these rotary toilets, and point sole blame on the incredibly high number of accidents/incidents to pilot error, then it seems there is only 2 possible reasons: 1. They are wrong; and don't support fact and true findings regarding the engineering lunacy in the design, or 2. The ones who actually believe these are safe/reliable (and not reliable to crash) are just confirming their level of common sense and intelligence.
I sure would hope for the former, but I see it as a combination.
My last issue in debating the robby safety/reliability; if so, they why do NONE of the other helicopters in the US history have any record that even comes close to the mechanical malfunction/failure rate of the robbys??? Sure, back in the 40's and 50's etc when the Bell47 was evolving...it was doing just that...Evolving! When problems were encountered, they were fixed or changed; that's why there are over 20 different Bell47 models, and not with just cosmetic changes! And they still don't have the record # of NON-pilot error accidents that robby does! No other helicopter even comes close; not the Hiller, not Enstrom, not the Schweitzer, not JetRanger, Hughes...etc.
As I understand, the robby has not changed it's design since conception with regards to the mechanical flaws (I do know they had different models, or names, but the design for safety has not changed significantly enough to ensure safety).
At least the true colors are showing in some parts of the US regarding the robby...it is unfortunate that more accidents are going to occur, and take the lives of uninformed passengers.
But I am sure that Mr Frank Robinson sleeps soundly every night, knowing his finances are secured in offshore accounts.
Thanks for your info, Lu!
keep up the great work.
the robby is not worth defending 'to the death' in my books!
seisfly
The pub to which I was referring is available at (some) aviation supply shops...and I am quite sure that it is a matter of discretion. Robbys are not that popular here, so info regarding them is readily available.
The NTSB link to their accident database is an excellent and very useful site! I have used that many times when aircraft shopping (f/w and helis)
My only question regarding the robbys and their proclaimed 'reliability and safety';
if these pilots and wannabes are so intent on defending these rotary toilets, and point sole blame on the incredibly high number of accidents/incidents to pilot error, then it seems there is only 2 possible reasons: 1. They are wrong; and don't support fact and true findings regarding the engineering lunacy in the design, or 2. The ones who actually believe these are safe/reliable (and not reliable to crash) are just confirming their level of common sense and intelligence.
I sure would hope for the former, but I see it as a combination.
My last issue in debating the robby safety/reliability; if so, they why do NONE of the other helicopters in the US history have any record that even comes close to the mechanical malfunction/failure rate of the robbys??? Sure, back in the 40's and 50's etc when the Bell47 was evolving...it was doing just that...Evolving! When problems were encountered, they were fixed or changed; that's why there are over 20 different Bell47 models, and not with just cosmetic changes! And they still don't have the record # of NON-pilot error accidents that robby does! No other helicopter even comes close; not the Hiller, not Enstrom, not the Schweitzer, not JetRanger, Hughes...etc.
As I understand, the robby has not changed it's design since conception with regards to the mechanical flaws (I do know they had different models, or names, but the design for safety has not changed significantly enough to ensure safety).
At least the true colors are showing in some parts of the US regarding the robby...it is unfortunate that more accidents are going to occur, and take the lives of uninformed passengers.
But I am sure that Mr Frank Robinson sleeps soundly every night, knowing his finances are secured in offshore accounts.
Thanks for your info, Lu!
keep up the great work.
the robby is not worth defending 'to the death' in my books!
seisfly
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Posts: n/a
To: Seismicpilot
It is for the same reason that some people refuse to change brands of toothpaste. Brand loyalty. At least that is what I see in the posts on this thread.
Also this is coupled with the training they get in the process of being certified in either the R22 or, the R44. They want to believe what they were told during that training and in no way wish to confront their instructors. Most of the people that check out in these helicopters don't have a high level of experience to fall back on so whatever they are told by their instructors is immediately cast in concrete.
Then. there are the high time pilots that so far haven't been bitten and as such refuse to admit to the limitations placed on them by various ADs.
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The Cat
It is for the same reason that some people refuse to change brands of toothpaste. Brand loyalty. At least that is what I see in the posts on this thread.
Also this is coupled with the training they get in the process of being certified in either the R22 or, the R44. They want to believe what they were told during that training and in no way wish to confront their instructors. Most of the people that check out in these helicopters don't have a high level of experience to fall back on so whatever they are told by their instructors is immediately cast in concrete.
Then. there are the high time pilots that so far haven't been bitten and as such refuse to admit to the limitations placed on them by various ADs.
------------------
The Cat
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Looks like the Cat has found an ally in his Robbie bashing but unlike him he just hates them because he tried to fly one and it made him look bad.
The reliability of the Robbie is excellent why else would the TBO's have been exdended?
The reason the MR divergence accident statistic is high is because it was caused by low rotor rpm. (We're taking below 60%) at this point you're done in ANY helicopter. After the Govenor became mandatory the rate has dropped dramatically.
The 300 almost never reaches TBO on the engine, without at least sticking or inhaling
a valve.Ditto for the Enstrom.The 47 operator needs three to keep one flying. Don't know about the Hiller.
If your engine quits doing seismic work pray that you're in a Long Ranger, Lama or R44 because there isn't much else that Autos as nice.Fly safe but quit the unfounded Robbie attacks.
PS: I'm shure you voted Gore .
The reliability of the Robbie is excellent why else would the TBO's have been exdended?
The reason the MR divergence accident statistic is high is because it was caused by low rotor rpm. (We're taking below 60%) at this point you're done in ANY helicopter. After the Govenor became mandatory the rate has dropped dramatically.
The 300 almost never reaches TBO on the engine, without at least sticking or inhaling
a valve.Ditto for the Enstrom.The 47 operator needs three to keep one flying. Don't know about the Hiller.
If your engine quits doing seismic work pray that you're in a Long Ranger, Lama or R44 because there isn't much else that Autos as nice.Fly safe but quit the unfounded Robbie attacks.
PS: I'm shure you voted Gore .