R44 fatal accident - tail boom failure?
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Update on May 1, 2006 in flight breakup
Hello All,
i have not posted hear in years, For all of you that have an interest in Robinson In-Flight breakups, I have news.
May 1, 2006 R44 Helicopter ferrying from Torrance to Ontario Canada broke up inflight.
Untitled Page for a reminder
We now have some answers that i feel compeled to let others know and decide on there own.
News Brief:
Families of 2 men killed in crash settle with Robinson Helicopter - The Daily Breeze
Family hopes good comes from tragedy - Chatham Daily News - Ontario, CA
Robinson settles case one day into trial: No pilot error or Passenger Input caused this crash.
Defective Rubber Mounts
This might put into perspective on this "chugging" and ramifications of experiencing violent shaking.
Thank-fully this pilot was not too high in the air as was able to come safety down.
http://www.aaib.gov.uk/cms_resources...FR%2010-07.pdf
Was not the case of the New R44 Helicopter ferrying to Canada.
These were the same part # rubbers that were on this fatal crash helicopter.
Softer rubbers, better ride. Harder (seasoned ) Rubbers- rougher ride
The Helicopter was violently shaken apart in air. Tailboom tearing and extruding straight rearwards on the stbd side followed by a some bending or crimping before tearing on the edges of the port side" that is what it was.
the swashplate broke, then pitch link let go, found 800 ft away from crash site. blades out of normal rotation, struck the cab several times prior final blow to cockpit.
pilot shut down everything, and was 200ft from ground.
In a despostion from Robinson's Chief Engineer , he admitted that a vibration in the main rotor mast of the R44 could cause the gear box to shake violently,. Robinson knew about this problem of mast rocking or " chugging" as it is sometimes called , since 1993 and continued selling the helicopter while making only minor adjustments to the rubber mounts and not informing pilots of the procedures to follow if such a problem occurred. Also in 2006 the time this helicopter was manufactured in the Robinson Factory, a batch of soft main Rotor gear box motormounts were used in R44's, making this self-exciting "chugging" problem more severe when and if it occurred.
This only confirms that it was neither Frank Verellen (pilot) or Leo Straatman (passenger) caused the accident to happen, only affirming what we already knew.
We are hoping with this outcome that it spurs enough inquiries to Robinson Company , NTSB and FAA to make changes in order to prevent another tragic accident from happening to a well-loved pilot.
Nothing can bring back our loved ones but if this trial and investigation helps save even one life our struggles and hard work will have been worth it.
Many more R44's and now R66's are showing same ugly traits. Let's keep informed!!!!
i have not posted hear in years, For all of you that have an interest in Robinson In-Flight breakups, I have news.
May 1, 2006 R44 Helicopter ferrying from Torrance to Ontario Canada broke up inflight.
Untitled Page for a reminder
We now have some answers that i feel compeled to let others know and decide on there own.
News Brief:
Families of 2 men killed in crash settle with Robinson Helicopter - The Daily Breeze
Family hopes good comes from tragedy - Chatham Daily News - Ontario, CA
Robinson settles case one day into trial: No pilot error or Passenger Input caused this crash.
Defective Rubber Mounts
This might put into perspective on this "chugging" and ramifications of experiencing violent shaking.
Thank-fully this pilot was not too high in the air as was able to come safety down.
http://www.aaib.gov.uk/cms_resources...FR%2010-07.pdf
Was not the case of the New R44 Helicopter ferrying to Canada.
These were the same part # rubbers that were on this fatal crash helicopter.
Softer rubbers, better ride. Harder (seasoned ) Rubbers- rougher ride
The Helicopter was violently shaken apart in air. Tailboom tearing and extruding straight rearwards on the stbd side followed by a some bending or crimping before tearing on the edges of the port side" that is what it was.
the swashplate broke, then pitch link let go, found 800 ft away from crash site. blades out of normal rotation, struck the cab several times prior final blow to cockpit.
pilot shut down everything, and was 200ft from ground.
In a despostion from Robinson's Chief Engineer , he admitted that a vibration in the main rotor mast of the R44 could cause the gear box to shake violently,. Robinson knew about this problem of mast rocking or " chugging" as it is sometimes called , since 1993 and continued selling the helicopter while making only minor adjustments to the rubber mounts and not informing pilots of the procedures to follow if such a problem occurred. Also in 2006 the time this helicopter was manufactured in the Robinson Factory, a batch of soft main Rotor gear box motormounts were used in R44's, making this self-exciting "chugging" problem more severe when and if it occurred.
This only confirms that it was neither Frank Verellen (pilot) or Leo Straatman (passenger) caused the accident to happen, only affirming what we already knew.
We are hoping with this outcome that it spurs enough inquiries to Robinson Company , NTSB and FAA to make changes in order to prevent another tragic accident from happening to a well-loved pilot.
Nothing can bring back our loved ones but if this trial and investigation helps save even one life our struggles and hard work will have been worth it.
Many more R44's and now R66's are showing same ugly traits. Let's keep informed!!!!
Join Date: Feb 2005
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Hmm, I was thinking about this thread last night and wondered where it had gone, and that drink i was sitting on, so decided the current bottle of Jameson’s was worth another couple of double shots as well.
The first thing my morning head has said is that we need a very simple AD or at least an SB, - check and remove mounts if they are part no. #### and replace with XXXXX at next hundred.
A Robinson safety notice detailing the dangers of fwd CofG, because of this "chugging" and a procedure to abate it if encountered.
In the other thread on the subject there was suggestion that this phenomena may account for many other accidents. Always dangerous jumping to those conclusions, but I can think of one with four POB fatal in the Kimberly that might? fit the bill.
Oh for the information back then.
The first thing my morning head has said is that we need a very simple AD or at least an SB, - check and remove mounts if they are part no. #### and replace with XXXXX at next hundred.
A Robinson safety notice detailing the dangers of fwd CofG, because of this "chugging" and a procedure to abate it if encountered.
In the other thread on the subject there was suggestion that this phenomena may account for many other accidents. Always dangerous jumping to those conclusions, but I can think of one with four POB fatal in the Kimberly that might? fit the bill.
Oh for the information back then.
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@ FLYINHY
As I understand it, you were close to the fatalities in an accident, and I am soory for your loss, however you cannot simply make speculative statements as fact and not have them questioned
The case was settled, and as the accident report was inconclusive, that means we will never know what happened. There is no evidence either for or against pilot error or passenger input. However in the same way that Robinson can be accused of carelessness with respect to the rubber mounts and chugging, the pilot was acting against safety notices about non-pilot passengers and the dual controls.
Perhaps I am reading too much into your statement, but there is once again no evidence either for or against chugging occurring on the Canada flight.
Once again, there is no evidence that it caused the loss of *any* pilots.
I fully support investigations into the chugging issue, as - from what I can see - do Robinson who also don't want their helicopters dropping out of the sky.
But whatever outcome those investigations have, it won't change the fact that the accident investigation causes are unknown. If pinning the blame in your own mind on a single one of the possible causes gives you some sense of closure, then that is a good thing for you.
The research is always helpful for future safety, but doesn't constitute proof of anything in the past.
[For the record, I have no affiliation with Robinson Helicopter Co., other than as a past owner and pilot]
Arfur
As I understand it, you were close to the fatalities in an accident, and I am soory for your loss, however you cannot simply make speculative statements as fact and not have them questioned
Robinson settles case one day into trial: No pilot error or Passenger Input caused this crash.
Defective Rubber Mounts
This might put into perspective on this "chugging" and ramifications of experiencing violent shaking.
Thank-fully this pilot was not too high in the air as was able to come safety down.
http://www.aaib.gov.uk/cms_resources...FR%2010-07.pdf
Was not the case of the New R44 Helicopter ferrying to Canada.
These were the same part # rubbers that were on this fatal crash helicopter.
Softer rubbers, better ride. Harder (seasoned ) Rubbers- rougher ride
This might put into perspective on this "chugging" and ramifications of experiencing violent shaking.
Thank-fully this pilot was not too high in the air as was able to come safety down.
http://www.aaib.gov.uk/cms_resources...FR%2010-07.pdf
Was not the case of the New R44 Helicopter ferrying to Canada.
These were the same part # rubbers that were on this fatal crash helicopter.
Softer rubbers, better ride. Harder (seasoned ) Rubbers- rougher ride
We are hoping with this outcome that it spurs enough inquiries to Robinson Company , NTSB and FAA to make changes in order to prevent another tragic accident from happening to a well-loved pilot.
I fully support investigations into the chugging issue, as - from what I can see - do Robinson who also don't want their helicopters dropping out of the sky.
But whatever outcome those investigations have, it won't change the fact that the accident investigation causes are unknown. If pinning the blame in your own mind on a single one of the possible causes gives you some sense of closure, then that is a good thing for you.
The research is always helpful for future safety, but doesn't constitute proof of anything in the past.
[For the record, I have no affiliation with Robinson Helicopter Co., other than as a past owner and pilot]
Arfur
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Chuging as Robinson puts it is PYLON WHIRL it is common with Bell style two bladed rotor systems . one blade flaps up and the other flaps down as a single unit.
As the blades flap to releave disemitry of lift. they also see different air loads. different loads in mass & drag so some times the pylon will turn not in line of the turning shaft but turn in a circle around the plyon with the shaft whipping from aerodynamic loads that are out of ballance in the plane of rotation, the effects are minimized by design with the rotor blade inplane stiffness & gearbox dampers. If the rubber in the R-44 is too soft & the C/G is a little out of limits the pylon could shake the tail off .
Look up pylon whirl , Hooks effect , Aeroelastic .
As the blades flap to releave disemitry of lift. they also see different air loads. different loads in mass & drag so some times the pylon will turn not in line of the turning shaft but turn in a circle around the plyon with the shaft whipping from aerodynamic loads that are out of ballance in the plane of rotation, the effects are minimized by design with the rotor blade inplane stiffness & gearbox dampers. If the rubber in the R-44 is too soft & the C/G is a little out of limits the pylon could shake the tail off .
Look up pylon whirl , Hooks effect , Aeroelastic .
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hillberg:
As far as I know (and I'm more than willing to be corrected), pylon whirl has only happened during touchdown autorotations on the 206 series. Standing by for other evidence.
As far as I know (and I'm more than willing to be corrected), pylon whirl has only happened during touchdown autorotations on the 206 series. Standing by for other evidence.
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The 206 L has the nodal beams that dephase & buckle the tail boom as the rotor Rpm decays on the landing phase of autorotation, The Bell 205 & UH 1 will do a good whirl when the simplex water tank fills with water and the pilots start to look like a load of laundry in an outa ballanced washing machine ( It starts small & grows with the change in C/G and load.)
Bad Txsn dampers too will add to the excitment, Or bad sprag mounts in the Hiller & Bell 47, or a bad isolation mount in the 206 Bs
Did a lot of vibration tests, funny what spinning things do in a helicopter.
Bad Txsn dampers too will add to the excitment, Or bad sprag mounts in the Hiller & Bell 47, or a bad isolation mount in the 206 Bs
Did a lot of vibration tests, funny what spinning things do in a helicopter.
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NTSB final report: Robinson R44 Raven II C-FICL
a loss of control and the divergence of the main rotor blade system from its normal rotational path for undetermined reasons.
Analysis
The Canadian certificated commercial helicopter pilot was conducting a cross-country delivery flight with a non-rated passenger occupying the copilot seat. The passenger and pilot together had previously made delivery flights from the Robinson factory to Canada. Two witnesses saw the helicopter just before it impacted the ground and reported that the tail boom had separated from the fuselage. No witnesses were identified who saw the initial breakup sequence. Both main rotor blades were bent downward at significant angles, with one blade having penetrated the cabin on the right side with a downward slicing front to rear arc. The primary wreckage debris field was approximately 500 feet long on an easterly heading. The helicopter sustained damage consistent with a high-energy, fuselage level, vertical ground impact. Detailed post accident investigation of the engine, the airframe, and the control systems disclosed no evidence of any preimpact anomalies. The removable cyclic was installed on the left side copilot's position, contrary to manufacturer's recommendations when a non-rated passenger is seated in the left seat. The removable pedals and collective for the left side were not installed. The cyclic controls for both the pilot's and copilot's positions were broken from their respective mounting points. The copilot's cyclic grip exhibited inward crushing. The Safety Board adopted a Special Investigation Report on April 2, 1996, following the investigation into R22 and R44 accidents involving loss of main rotor control and divergence of the main rotor disk, which included a finding that the cause of the loss of main rotor control in many of the accidents "most likely stems from a large, abrupt pilot control input to a helicopter that is highly responsive to cyclic control inputs."Probable Causeand Findings
The National Transportation Safety Board determines the probable cause(s) of this accident to be:a loss of control and the divergence of the main rotor blade system from its normal rotational path for undetermined reasons.
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Well that's disappointing. I attended the factory class that ended right before this accident... I think they must have been in the class although I didn't remember them specifically. It came as a shock when I got home and heard about the accident.. The pilot was not an inexperienced guy. I was really hoping we would get a concrete cause to the accident... Still wonder if they did something ( low gee? Auto? ) that went bad, or whether there was simply a mechanical issue with the aircraft that took a few hours to manifest itself?
If you have not read the original report, it is very sobering. I am infinitely familiar with one of the accidents sited and fairly familiar with another 2 of them:
NTSB Special Investigation Report 96-03 into Robinson Helicopters
NTSB Special Investigation Report 96-03 into Robinson Helicopters
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This is ancient history. The single, key point of the entire report is on Page 29, bullet eight (8):
"There have been no in-flight main rotor loss of control accidents in the United States involving the R22 or R44 helicopter since early 1995, when the Federal Aviation Administration issued airman information alerts, airworthiness directives, a flight standardization board report, and Special Federal Aviation Regulation 73, all of which pertain to the operation of the R22 and R44 helicopters."
Fly, instruct and maintain it right and it will treat you right. Fail to do so at your own peril. There is no better example of this than to compare US accident rates vs. those outside the US where SFAR 73 or it's equivalent has not been respected.
This is not to say there haven't been improvements to the breed. Bladder tanks, new rotor blade designs, etc., all have been helpful in reducing accident rates or the results thereof. But the single most important improvement is SFAR 73, which is really applicable to any two-bladed, teetering, low inertial rotor head design. Of course there really aren't any flying except the Robinson product line, with the possible exception of the Mosquito and Rotorway homebuilts.
I do have to say, however, that while it was easy to understand my instructor's admonitions with respect to low-G maneuvers and turbulence, their focus on smooth and small control inputs was not quite as obvious. This latter point is not well covered by either SFAR 73 nor the usual cohort of helicopter aerodynamics references, although it does make sense from a general pilot skills perspective. That said, watching mustering operations in the R22 tends to provide some conflicting evidence in this respect (not that I've done this personally). However I have had demonstrated, by my instructor, how repeated, aggressive control inputs can drag down rotor RPM.
Fly the machine you have, not the machine you wish you had.
"There have been no in-flight main rotor loss of control accidents in the United States involving the R22 or R44 helicopter since early 1995, when the Federal Aviation Administration issued airman information alerts, airworthiness directives, a flight standardization board report, and Special Federal Aviation Regulation 73, all of which pertain to the operation of the R22 and R44 helicopters."
Fly, instruct and maintain it right and it will treat you right. Fail to do so at your own peril. There is no better example of this than to compare US accident rates vs. those outside the US where SFAR 73 or it's equivalent has not been respected.
This is not to say there haven't been improvements to the breed. Bladder tanks, new rotor blade designs, etc., all have been helpful in reducing accident rates or the results thereof. But the single most important improvement is SFAR 73, which is really applicable to any two-bladed, teetering, low inertial rotor head design. Of course there really aren't any flying except the Robinson product line, with the possible exception of the Mosquito and Rotorway homebuilts.
I do have to say, however, that while it was easy to understand my instructor's admonitions with respect to low-G maneuvers and turbulence, their focus on smooth and small control inputs was not quite as obvious. This latter point is not well covered by either SFAR 73 nor the usual cohort of helicopter aerodynamics references, although it does make sense from a general pilot skills perspective. That said, watching mustering operations in the R22 tends to provide some conflicting evidence in this respect (not that I've done this personally). However I have had demonstrated, by my instructor, how repeated, aggressive control inputs can drag down rotor RPM.
Fly the machine you have, not the machine you wish you had.
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Great thread.
I read this with lots of interest because I have ordered a new R44 and delivery date is around end of April - early may almost exactly 14 years since this accident . I am flying to factory with my CFI to fly helicopter back home. I am hoping robinson makes better quality helicopters since then
I read this with lots of interest because I have ordered a new R44 and delivery date is around end of April - early may almost exactly 14 years since this accident . I am flying to factory with my CFI to fly helicopter back home. I am hoping robinson makes better quality helicopters since then
