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Kaman stop production of K-Max

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Kaman stop production of K-Max

Old 20th Jan 2023, 12:27
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Kaman stop production of K-Max

Sad news but due to low amrket demand, Kaman is stopping production of the K-MAx

https://aviationweek.com/defense-spa...max-helicopter

Last one I saw was Heli Expo 2020 (my pic below)


and before that was January 8th 2016 when I went up to west midlands to see Rotex at work assisting the Uni of Central England with CO2 silo construction for their natural sciences department, (my photos below)



cheers
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Old 20th Jan 2023, 12:56
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Out of 60 K-Max's produced, 16 have crashed and been written off - that's 27% of the fleet! While admittedly this is a small production run that subsequently skews the numbers, I can't actually think of any aviation product of any kind that has suffered an attrition rate as high as this?

The K-Max remains an extremely popular helicopter and I know operators, pilots, and mechanics that love them, and have no qualms about operating them. This is the second time that production has been terminated, but maybe it'll come back again in the future. It was extremely successful as an autonomous unmanned platform, and it is hard to believe it won't reappear at some point in the future in that same role.
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Old 20th Jan 2023, 17:24
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Originally Posted by Cyclic Hotline
Out of 60 K-Max's produced, 16 have crashed and been written off - that's 27% of the fleet! While admittedly this is a small production run that subsequently skews the numbers, I can't actually think of any aviation product of any kind that has suffered an attrition rate as high as this?
Out of interest, I believe 18 of A-12/SR-71 production totalling 46 aircraft were lost - four crew were lost.
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Old 20th Jan 2023, 17:41
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Originally Posted by treadigraph
Out of interest, I believe 18 of A-12/SR-71 production totalling 46 aircraft were lost - four crew were lost.
12, 4 because of tire failure.
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Old 20th Jan 2023, 18:10
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Originally Posted by B2N2
12, 4 because of tire failure.
12 SR-71 (out of 32) and 6 A-12 (out of 15) - as far as I'm aware the SR-71 was a few feet longer and somewhat heavier but essentially a developed A-12. Miscounted earlier - 47 airframes!
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Old 21st Jan 2023, 02:45
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Chopper2004: That is unfortunate news. Makes me wonder what is still in production at Kaman?

It is fascinating to see the K-Max fly and its rotors intermesh when they are so close together.

Originally Posted by Cyclic Hotline
Out of 60 K-Max's produced, 16 have crashed and been written off - that's 27% of the fleet! While admittedly this is a small production run that subsequently skews the numbers, I can't actually think of any aviation product of any kind that has suffered an attrition rate as high as this?...
Well Cyclic, treadigraph shared interesting stat for A-12 / SR-71 losses at 38.3% combined, but then look at the Luftwaffe's fleet of F-104's. According to Wikipedia: "The Germans lost 292 of 916 aircraft and 116 pilots from 1961 to 1989, its high accident rate earning it the nickname "the Widowmaker" from the German public". That is a 31.9% loss rate during that period for this far larger fleet.

Would be informative to find out how many of the K-Max accidents were due to some sort of mechanical issues as opposed to those due to other causes given higher risk ops they are probably often conducting (low level, sling loads, firefighting).
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Old 21st Jan 2023, 22:31
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Well Cyclic, treadigraph shared interesting stat for A-12 / SR-71 losses at 38.3% combined, but then look at the Luftwaffe's fleet of F-104's. According to Wikipedia: "The Germans lost 292 of 916 aircraft and 116 pilots from 1961 to 1989, its high accident rate earning it the nickname "the Widowmaker" from the German public". That is a 31.9% loss rate during that period for this far larger fleet.

A total of 890 Meteors were lost in RAF service (145 of these crashes occurring in 1953 alone), resulting in the deaths of 450 pilots. Total in service 3275
So a loss rate of 36%. With a higher fatality rate.

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Old 22nd Jan 2023, 01:48
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Originally Posted by Cyclic Hotline
It was extremely successful as an autonomous unmanned platform,
There were two aircraft. One crashed. Not extremely successful.
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Old 22nd Jan 2023, 22:30
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Considering the type of work the K-Max did and being single engine it is not surprising there were crashes.

Logging, fire fighting, construction work....all low altitude operations with lots of hovering at max power, and rough loading of forces on the airframe especially during logging work....as compared to standard utility helicopter accident rates....no surprise the K-Max suffered losses.

Think not....look at Huey Helicopters in logging operations....they crashed with great frequency.
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Old 24th Jan 2023, 17:31
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Originally Posted by Cyclic Hotline
Out of 60 K-Max's produced, 16 have crashed and been written off - that's 27% of the fleet! While admittedly this is a small production run that subsequently skews the numbers, I can't actually think of any aviation product of any kind that has suffered an attrition rate as high as this?
Bell 214B: - Hold my beer...
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Old 24th Jan 2023, 23:50
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Bell 204's.....doing heli-logging....like playing Russian Roulette with five loaded chambers in a six shot revolver!

Last edited by SASless; 25th Jan 2023 at 00:32.
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Old 3rd Feb 2023, 15:31
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Originally Posted by helichris
There were two aircraft. One crashed. Not extremely successful.
This is correct, but the accident was preventable. This report is referenced in this story. https://www.washingtonpost.com/news/...from-crashing/
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Old 3rd Feb 2023, 15:33
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And another one gone this week.
IDENTIFICATION Date: 24-JAN-23 Time: 21:00:00Z Regis#: N202WM Aircraft Make: KAMAN Aircraft Model: K1200
Event Type: ACCIDENT Highest Injury: NONE Aircraft Missing: No
Damage: SUBSTANTIAL LOCATION City: SWEET HOME State: OREGON Country: UNITED STATES DESCRIPTION Description: AIRCRAFT, SWEET HOME, OR:
N202WM, KMAX, ROLLED OVER DURING LANDING WHILE CONDUCTING LOGGING OPERATIONS APPROX 20 E OF SWEET HOME. POB: 1, INJURIES: NONE, DAMAGE: SUBSTANTIAL. 01/24/2023 2100Z
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Old 3rd Feb 2023, 15:48
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Originally Posted by snotcicles
Bell 214B: - Hold my beer...
Yes, you're correct. Out of a production run of 70 helicopters, 44 were written off. That's a 63% loss rate.
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Old 7th Feb 2023, 05:38
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Originally Posted by Cyclic Hotline
This is correct, but the accident was preventable. This report is referenced in this story. https://www.washingtonpost.com/news/...from-crashing/
The Washington Post article also indicates there must have been at least 3 of these remotely controlled K-Max built as the other 2 were being returned from Afghanistan.
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Old 24th May 2023, 09:58
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https://verticalmag.com/news/servo-f...l-k-max-crash/

Servo flap failure preceded fatal K-Max crash

BY ELAN HEAD | MAY 22, 2023Estimated reading time 10 minutes, 36 seconds.

A recent investigation by the U.S. National Transportation Safety Board (NTSB) determined that a servo flap failed before the catastrophic in-flight breakup of a K-Max helicopter, but neither the manufacturer, Kaman, nor the Federal Aviation Administration (FAA) has issued guidance on how to prevent such failures in the future.
The Kaman K-Max has a unique intermeshing rotor system that relies on servo flaps to change the pitch of the rotor blades. Kaman PhotoPilot Tom Duffy was killed when his helicopter came apart during firefighting operations in Pine Grove, Oregon, on Aug. 24, 2020. An experienced pilot flying for his family’s company, Montana-based Central Copters, Duffy had more than 2,000 hours of flight experience in K-Max helicopters at the time of the crash.

First certified by the FAA in 1994, the K-Max has a unique intermeshing rotor system, featuring twin counter-rotating, two-bladed rotor systems mounted side-by-side on individual pylons. A single transmission normally keeps the blades of each rotor system 90 degrees out of phase with the other’s and the pylons are tilted to allow the blades to clear the opposing rotor hub.

Control of the blades is accomplished through servo flaps, small airfoils mounted on the trailing edge of each blade around three-quarters of the way to the tip. The pilot’s flight control inputs are transferred through rods to the servo flaps, which deflect the airstream to twist the rotor blades and change their pitch.

Because the pilot is only moving the servo flaps, the required forces are relatively small. That allows the aircraft — which has a maximum gross weight of 12,000 pounds (around 5,440 kilograms) with external load — to be flown without hydraulic assistance.
The Central Copters K-Max, registered as N314, crashed while pilot Tom Duffy was filling a water bucket on a long line. The lack of damage to the long line demonstrated that both rotor systems and pylons had separated from the fuselage while the helicopter was in flight. Central Copters/NTSB PhotoIn the Oregon crash, NTSB investigators determined that a crack in one of the left rotor system’s servo flaps grew progressively, ultimately leading to the separation of the flap’s afterbody — the panels attached to the spar that form the airfoil shape. This resulted in a loss of control of the associated left blade.

The NTSB concluded that the left rotor blades then struck the right rotor blades, causing the in-flight separation and breakup of the left blades. At the time, Duffy was hovering at around 140 feet over a river, filling the water bucket attached to his long line. The helicopter rolled to the left as it descended and impacted the river.

Investigators were unable to determine why the servo flap failure ultimately resulted in a collision between the left and right rotor systems. They said it was likely that flight control inputs, including the pilot’s responses to an abnormal vibration in the rotor system, were a factor in the catastrophic outcome, but the lack of flight data precluded analysis of the control inputs leading up to the collision.

The NTSB noted that in 2009, the same helicopter (then operating under a different registration) experienced an event in which an entire servo flap separated from its attachment brackets while in flight, but the pilot was able to land the aircraft safely.

However, the agency also called attention to another accident involving a K-Max operated by Woody Contracting in Donnelly, Idaho, on June 16, 2010. Pilot Roy Kettle had been lifting a large log using a 200-foot long line when two of the helicopter’s counter-rotating blades collided with each other, causing a crash that resulted in Kettle’s death.
Investigators determined this servo flap from the Central Copters K-Max’s left rotor system failed prior to the collision between the rotor systems. NTSB PhotoInvestigators for that accident were likewise unable to determine the reason for the collision, but found that the afterbody had separated from the servo flap on one of the left rotor blades.

There is industry speculation that something similar might have happened in the crash of a Black Tusk Helicopters K-Max in Killam Bay, British Columbia, on Oct. 4, 2021. Pilot Gary Weber was killed when his helicopter impacted the water while carrying logs over the bay. That accident is still under investigation by the Transportation Safety Board of Canada (TSB), but docket material for the Central Copters crash indicates that TSB representatives examined that wreckage last June for “comparative analysis” to the Black Tusk crash.

Vertical submitted multiple questions to Kaman, including whether the company has issued any new guidance to operators as a result of either crash or has plans to do so in the future. A Kaman spokesperson said the company was unable to comment due to the ongoing investigation. When asked whether the FAA plans to issue an airworthiness directive for K-Max helicopter blades, a spokesperson said via email, “We don’t have anything to report at this time.”

Meanwhile, the family of Tom Duffy has sued Kaman in U.S. District Court, contending that “a defectively designed, manufactured, and marketed servo flap on the blades of his K-Max helicopter caused the crash” and that the 2020 crash was “substantially identical to a previous accident about which Kaman had knowledge.”
In a 2010 crash, a servo flap afterbody also separated along a straight spanwise line just aft of its pivot point. NTSB PhotoKaman denied the allegations, initially claiming instead that Duffy “negligently operated the K-Max helicopter,” and that Central Copters failed to adequately maintain the aircraft, and/or failed to adequately train and supervise Duffy. However, both parties agreed to the dismissal of Kaman’s counterclaims on May 19.

The K-Max is a niche helicopter designed for repetitive heavy-lift operations, and just 60 aircraft were made across two production runs. After ceasing initial production in 2003, Kaman decided to restart the line in 2015. Yet, the company announced earlier this year that it was discontinuing the K-Max, citing “low demand and variation in annual deliveries, coupled with low profitability and large working capital inventory requirements.”

Kaman said it would continue to support the existing K-Max fleet in operation, but further investment in product improvement seems unlikely. In 2019, the company announced a program to design and certify all-composite rotor blades for the K-Max, which still relies on rotor blade spars made from Sitka spruce. The all-composite blades never materialized, though, and Kaman declined to comment on the status of the program.
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Old 24th May 2023, 11:03
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That looks like a substantial failure of a critical flight control component, and not only one occurrence but at least three times (once the entire servo flap). The Vertical magazine article doesn't say anything about the nature of the servo flap failures, but presumably that is covered by NTSB and will also be by TSB Canada once they have finished their investigation. If fatigue, I wonder whether it could have reasonably been detected during regular inspection but was somehow missed prior to both accident? Or could it have remained hidden until a sudden failure?
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Old 24th May 2023, 12:26
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Originally Posted by helispotter
I wonder whether it could have reasonably been detected during regular inspection but was somehow missed prior to both accident? Or could it have remained hidden until a sudden failure?
I flew the SH-2F, which also has the servo flap system. You can fly that bird with no hydraulic pressure - it's a 13,000 pound helicopter, roughly, at max gross weight.

I am not sure if the servo flap system between K Max and SH-2F is identical, but I suspect it is very similar. The amount of play in the tower rods (from the azimuth up to the rotor head area) and the amount of play at the end of the clevis where it was attached to the flap itself was an inspection item on each daily / turnaround.
I am not sure how the K-max is maintained, but I'd be surprised if those connection points weren't as closely watched as on the SH-2F.
Yes, that servo flap is a primary flight control.

Digging back into old memory here:
There was an infamous (among the H-2 community) accident IIRC the 1970s (might have been an SH-2D, but I think it was an F).
Something came loose among the upper transmission doors, in flight, and ended up taking out a servo flap on one of the blades.
Nobody walked away from that crash.
As I recall the brief from our safety officer almost 40 years ago, the blade more or less went divergent and impacted the body of the aircraft at flight RPM.
One of our preflight items was the security of a locking pin on the aft clamshell doors - we were taught (in the RAG) that it had been added to prevent the doors from opening in flight after that accident. (Another day, I can share with you why the bolts in the azimuth were added).

Sorry to see the K Max running into problems, it's a unique bird that has done a lot of hard work over the years.
At one point (back in the 90's) the US Navy was proposing to have it do VERTREP from Military Sealift Command ships, as a replacement for the CH-46. The difficulties in getting the night / IFR certification, and instrumentation, proved to be too big of a hurdle to overcome.

A comment on the lawsuit: I am skeptical of the 'design flaw' assertion. My suspicion is that it was more likely either (1) maintenance error or oversight as a root cause, or (2) a flaw in the fabrication of one of the parts that make up that assembly.
I fail to see how one could blame the pilot, though, if the servo flap fails and / or falls off.
The loss of that critical flight control surface would mean that the blade would be all over the place as it rotated, and it will end in tears rather quickly at that point.

Last edited by Lonewolf_50; 24th May 2023 at 12:45.
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Old 24th May 2023, 12:43
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Originally Posted by Lonewolf_50
...A comment on the lawsuit: I am skeptical of the 'design flaw' assertion,and believe it more likely that maintenance error or oversight as a root cause.(Or perhaps a fabrication defect?)
I fail to see how one could blame the pilot, though, if the servo flap fails and / or falls off.
The loss of that critical flight control surface would mean that the blade would be all over the place as it rotated, and it will end in tears rather quickly at that point.
Thanks for the insights. Yes, I thought the same re Kaman (or their lawyers) apparently seeking to blaming the pilot. Could understand if they had evidence of aircraft being flown outside its operating limits by the pilot. Same applies to blaming maintenance, unless they had actual evidence of poor inspections etc.
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Old 24th May 2023, 15:34
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The difficulties in getting the night / IFR certification, and instrumentation, proved to be too big of a hurdle to overcome.
​​​​​​​Thanks for that Lonewolf, I had vague recollections of reading about it, wondered what had become of it.
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