Fatal AR1 crash 12/16/2020

fara

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No I did not cut up McCutchens. Just tried them for testing (the 29 foot ones we were supplied for testing) and decided not to use them because of their divergent behavior above 70 mph. McCutchens were really flexible and that actually was part of the problem but in torsional axis.

You want clearance yes. Its not a bad thing but remember what you see by tilting it back is a little meaningless in the sense that in a blade flap you will be at least 1.5 feet lower than that. The blade is not straight when blade sailing, flap is happening. It has a wave in it. It will likely go above the prop arc and droop down in a wave and hit the tail and next time (rev) the wave may catch one prop blade and another a bit lower and so on. It depends on the frequency and engine RPM and all of those interactions. Nothing straight in that phenomenon so this article from BCAR Sec T and from ASRA is not done by someone who understood gyroplanes or even rotorcraft. Its a blind prescriptive rule. It doesn't hurt though. One may argue that it helps if you have a blond moment and let go of the stick when starting pre-rotation (may be). It however needs to be understood that in a blade flap, blade sailing and in flight unloaded rotors, this rule will not do much. The rotors will droop down and touch something. Because all machines in Australia via ASRA system must meet this rule and yet I am sure if you search you can find many examples of gyroplanes with blades cut tails etc. from there.

Remember for a spinning rotor to touch the tail on an AR-1 or MTO where the tail at full aft stick and touching back teeter stop is into the tail a bit, the rotor RPM without flapping has to be pretty darn low. Obviously I can easily takeoff pre-rotating to 150 RRPM and pull the stick fully back and move forward and takeoff so without flapping the rotor RPM has to fall way below 160 to touch the tail. Or you are into a flap or in the air you are unloaded. If you are in those disaster scenarios it doesn't matter what the symptoms are. You have much bigger problems.

The Aero-elastic study of autorotative rotors was done in this Ph.D thesis in the UK and they used "McCutchen" blades.
Not necessary to read and understand the 241 pages of the thesis. Just read the abstract (first 5 pages) 4 times and understand what conceptually was found. Basically torsional rigidity, flexure, position of mass balance in the blade compared to its elastic axis all have to be considered. I can tell you McCutchen blades certainly the large ones did not understand or cared for this stuff and when I offered help to correct it, well I got some words back to the effect that I was in diapers when they were making blades or something like that

 
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Tyger

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Ok and? Are you telling me that in a blade flap Magni blade cannot hit the tail? Have you talked to your instructor about what happens in a blade flap? Unless your tail clears the blade by 2+ feet you are still going to hit it.
Yes, I understand perfectly well about blade flap. You don't have to be so condescending all the time. I was pointing out that your assertion about the clearance on the Magni was not at all accurate. When I point that out, your answer is "OK, and?" I wonder if your blanket assertion about "two feet" with these blades is as accurate.
 
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fara

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Yes, I understand perfectly well about blade flap. You don't have to be so condescending all the time. I was pointing out that your assertion about the clearance on the Magni was not at all accurate. When I point that out your answer is "OK, and?" I wonder if your blanket assertion about "two feet" with these blades is as accurate.

I think you need to ask that of Magni if they think your blade clearance at rest will "guarantee" your blades not hitting your tail in a bad blade flap or in flight in unloading the rotors. Its clear to me I am not going to convince you of anything and its pointless arguing about it. In any case whether you hit your tail, your prop, your windshield or not, is pointless. Those are simply symptoms. The main problem is flap or if applicable in the air unloading and rotor speed decay and loss of rotor thrust. Even you hit nothing, you are still coming down. When you lose rotor speed in flight, its a done deal. When you have bad enough rotor flap on the ground its a done deal and your gyro is damaged significantly and usually tipped over
 

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Tyger

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I think you need to ask that of Magni if they think your blade clearance at rest will "guarantee" your blades not hitting your tail in a bad blade flap or in flight in unloading the rotors. Its clear to me I am not going to convince you of anything and its pointless arguing about it. In any case whether you hit your tail, your prop, your windshield or not, is pointless. Those are simply symptoms. The main problem is flap or if applicable in the air unloading and rotor speed decay and loss of rotor thrust. Even you hit nothing, you are still coming down. When you lose rotor speed in flight, its a done deal. When you have bad enough rotor flap on the ground its a done deal and your gyro is damaged significantly and usually tipped over
Nothing in this world is guaranteed, if you ask me. I don't disagree with anything you say about the consequences of blade flapping in flight (or on the ground), except what seemed to be your assertion that a flapping blade will necessarily strike the tail of any gyroplane.
 

fara

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Nothing in this world is guaranteed, if you ask me. I don't disagree with anything you say about the consequences of blade flapping in flight (or on the ground), except what seemed to be your assertion that a flapping blade will necessarily strike the tail of any gyroplane.

Ok in a minor flap obviously no. But in a severe flap very likely. I hope that helps. Unloaded rotors almost always chop something but that chopping or touching something isn't the root cause. Its the result of what has happened. If by luck they did not hit something, unfortunately the end result will still be the same. This is one scenario where I guess a BRS could help for a person who has rehearsed its activation has a plan for its use present in their mind. However BRS requires 800 feet to guarantee full deployment.
We used them in trikes 80% of the time and one of the lessons in emergency procedures was activation procedure of the BRS and having the mindset to activate it early enough. Trikes also don't handle weightlessness or negative G but trike pilots develop a very good sense of when they barely start to feel their bottom lose G force.
 
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EI-GYRO

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Ok and? Are you telling me that in a blade flap Magni blade cannot hit the tail? Have you talked to your instructor about what happens in a blade flap? Unless your tail clears the blade by 2+ feet you are still going to hit it.
Well, Magnis seem to have a lot fewer takeoff incidents than others. Whether this is due to better rotor clearance or a prerotator which allows continued operation with the stick coming back, or both, I will leave others to argue. Better split up of the brake release-stick back- throttle forward may also be a factor, IMO.

Edited to add; I don't disagree with your comments on the behaviour of flapping blades.
 

XXavier

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Well, Magnis seem to have a lot fewer takeoff incidents than others. Whether this is due to better rotor clearance or a prerotator which allows continued operation with the stick coming back, or both, I will leave others to argue. Better split up of the brake release-stick back- throttle forward may also be a factor, IMO.

Edited to add; I don't disagree with your comments on the behaviour of flapping blades.

Magnis are solid constructions made by experienced people in a modern and well-equipped factory. They are, in my opinion, the best and safest gyros of the 'big three...'.
 

ventana7

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As we continue to try and understand accidents and their causes I want to give a shout-out to Abid for his objectiveness and openness in the process. As a businessman seeing two of your gyros in accident threads in a single week must be terrible, especially knowing the pilots.

When this used to happen in the RAF days all we got was BS and obfuscation from the company so that makes Abid’s openness all the more appreciated as a contribution towards all our long term safety.

Rob
 

TyroGyro

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Magnis are solid constructions made by experienced people in a modern and well-equipped factory. They are, in my opinion, the best and safest gyros of the 'big three...'.

Statistically, AutoGyro-GmbH are the "safest". 1% of hulls involved in fatals.
Then Magni - 1.6%
Then ELA - 4.5%

There are variations between models within manufacturer, however.

Is any of this really statistically significant? The $64,000 question...

ELA's problem, I believe, is not its machines, but where they are concentrated - disproportionately in countries with lower standards of regulation and training. (maybe because ELAs are slightly cheaper than its competitors?)

Beyond that, there is maybe a hint that enclosed tandems (including ELAs) are just slightly safer than the rest, which appear much of a muchness (after taking account of ELA's general "problem").
 
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fara

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Well, Magnis seem to have a lot fewer takeoff incidents than others. Whether this is due to better rotor clearance or a prerotator which allows continued operation with the stick coming back, or both, I will leave others to argue. Better split up of the brake release-stick back- throttle forward may also be a factor, IMO.

Edited to add; I don't disagree with your comments on the behaviour of flapping blades.

I do not have any information contrary to your assertion and have not looked for it either. We also have had only a few blade flap incidents mainly because some people would not take proper training and think they know better or they are rushed due to taking an expedited takeoff clearance from ATC with other traffic on final. They usually flap within a few seconds of ground roll starting because they pull the stick back at 100 rotor RPM and then try to speed up to get out quickly. This is all pilot induced and the problem has to be corrected with pilot attitude and pilot action not in the machine. There have been a couple of Magni incidents even recently but they are not reported. Were not flapping accidents though. Again nothing to do with Magni machines. Its all pilot error. I like Magni machines except they have a very heavy feel. Heavier than most other gyroplanes normally. May be they are good for older pilots who are coming from flying heavy airplanes because that's the feel they are used to and their brains have that feel mapped and its difficult for them at an older age to remap it now (without spending appropriate longer amount of time with an instructor or safety pilot which I think happens rarely). Just speculation but it may well have something to it.
 
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fara

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Statistically, AutoGyro-GmbH are the "safest". 1% of hulls involved in fatals.
Then Magni - 1.6%
Then ELA - 4.5%

There are variations between models within manufacturer, however.

Is any of this really statistically significant? The $64,000 question...

ELA's problem, I believe, is not its machines, but where they are concentrated - disproportionately in countries with lower standards of regulation and training. (maybe because ELAs are slightly cheaper than its competitors?)

Beyond that, there is maybe a hint that enclosed tandems (including ELAs) are just slightly safer than the rest, which appear much of a muchness (after taking account of ELA's general "problem").


That's an interesting stat. Usually the rate of accidents in GA is given by accidents per 10k hours of activity. Gyroplanes simply are not the population numbers to really be able to truly determine this or use this as a valid figure. Too few. Having few gyroplanes around skews the data and makes it somewhat invalid. However, its not completely useless. 381 people were killed in general aviation accidents in the US in 2018 and that included Part 135 operations that are much more heavily regulated. Insurance carriers in aviation have decided that their data shows that if you are 75 years or older, you are too much risk to insure in any category of aircraft unless you are an existing customer. Obviously they have the data and they are dealing with the lawsuits so I can only assume they know what they are talking about.

I think ELA did have some structural issues with some welding and perhaps their blades at one point but having trained in an ELA open cockpit and then transitioned to an AR-1 personally, I did not find much anything wrong with it in terms of safety in the basic design. Just like anything else, it has small caveats that you learn about and incorporate in your handling and I have yet to find a machine Magni included that is without any. Engine torque, moments due to thrust line mismatch with CG, light or heavy handling, power yaw and pitch couplings are all facts of life in almost all aircraft. P factor and PTE are facts of life in anything that swings a propeller. Unloading of rotors and low G pushover and mast bumping is a fact of life in a Robinson, Huey, Jet Ranger etc. They are all handled by training and getting through to the pilot what actions are simply a no no. Obviously airplane pilots are the biggest candidates on doing the maneuvers that can create those scenarios so even more time needs to be spent with them

What I find missing is any national body or club asking their members to fill a survey out in an easy way on a website that collects how many hours are truly being flown on a national level in gyroplanes and then see how many fatal accidents happen. I don't think that is being done or if it is its so far hidden that I in the industry don't even know about it and if I don't know shame on the clubs. Its something that can be done on a website and with a developer and a simple database for a couple of thousand dollars. In absence of simple things of value like this I find it hard to gauge what national clubs for gyroplanes are worth and what they are doing and why should I promote their membership. This holds true for trikes as well although clubs like BMAA and LAA in the UK do a lot more there
 
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TyroGyro

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I have estimated UK hours per machine accurately. I can find no reason to suppose the rest of the world is not in the same overall ballpark.

Using hulls as a proxy (and there are now about 5000 Big-3 worldwide) is a valid alternative approach. There is no reason to suppose ELAs fly significantly more hours than AutoGyros, per machine, for example.

The safest countries to fly in appear to be Italy, Germany, UK, USA...

A lot less safe: Australia, France, South Africa, Spain.

Rest of world: too few machines from which to draw firm conclusions.

Caveats: overall it appears the worldwide safety record has been improving consistently for the past 10 years.
Some of the countries listed above may be improving at faster rates than others (this is all rear-view mirror data I am using)
South Africa had one notorious screw-up that took the lives of I think 3 gyro pilots. That would significantly impact SA's apparent "safety" for the worse...
 
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ventana7

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The safest countries to fly in appear to be Italy, Germany, UK, USA...

A lot less safe: Australia, France, South Africa, Spain.

Rest of world: too few machines from which to draw firm conclusions.
Interesting but probably misleading. I lived in Australia and first learned to fly gyros there. Their equivalent of the FAA made the gyro association the regulating body of the sport- like hang gliders did in the US. Consequently their regulations and oversight and accident investigations were light years ahead of the US- where the FAA tried to just sweep gyros under the rug. When I was there the safety officer for the organization was my gyro CFI who was also a senior check airman for Quantas on 747-400s. EVERY accident was thoroughly investigated, conclusions drawn and if necessary changes made in regulations.

I would say their regulartory climate and instruction are far more stringent than in the US...BUT a huge use of gyros is mustering cattle. It's even more unforgiving than ag spraying- all day long at 150'AGL yanking and banking. Probably contributes to a high accident rate.

Rob
 

TyroGyro

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Yes different countries have different environmental and usage patterns, as well as regulatory, training and even cultural differences.

How we control for these factors when assessing a country's "safety" is open for discussion...

I restrict my analysis to the Big-3, which as far as I know are not often used for mustering in Oz. So that's not the reason why they (the Big-3) seem to have (had) a relatively poor safety record Down Under.

FWIW, three were wire/tree strikes. One was insecure cargo. One was poor home maintenance.

Is Australia "intrinsically" less safe? Almost certainly not.

Because, the world over. Gyros don't kill people: people kill gyros....

It just happens more often in some countries, compared to others. That's all.
 
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Illini85

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What I find missing is any national body or club asking their members to fill a survey out in an easy way on a website that collects how many hours are truly being flown on a national level in gyroplanes and then see how many fatal accidents happen. I don't think that is being done or if it is its so far hidden that I in the industry don't even know about it and if I don't know shame on the clubs. Its something that can be done on a website and with a developer and a simple database for a couple of thousand dollars. In absence of simple things of value like this I find it hard to gauge what national clubs for gyroplanes are worth and what they are doing and why should I promote their membership.
I can see a future where a completed survey of this type is a requirement of one's license. Nobody would like the intrusion but it could yield some useful data.
 

rdalcanto

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Back to my Dad's take off.... I believe the 3 changes in pitch attitude may have been attempts at trim adjustments or feeling the stick pressure. They are definitely not negative G, and I don't see how they could have caused a significant change in the rotor rpm. I practice vertical descents from 1000-1500 AGL near the start of the runway into a "dive" to land on the 1,000 foot markers all the time, as seen in this video. Never seen significant rotor rpm decay. Next time I fly I will video the rotor rpm gauge as I lower the nose on a climb.
 

GyroCFI

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Back to my Dad's take off.... I believe the 3 changes in pitch attitude may have been attempts at trim adjustments or feeling the stick pressure. They are definitely not negative G, and I don't see how they could have caused a significant change in the rotor rpm. I practice vertical descents from 1000-1500 AGL near the start of the runway into a "dive" to land on the 1,000 foot markers all the time, as seen in this video. Never seen significant rotor rpm decay. Next time I fly I will video the rotor rpm gauge as I lower the nose on a climb.
You're really not unloading the rotor when you do a vertical descent and then a "dive" to land unless you're carrying power through the initial pushover to the dive. It's a maneuver I've taught to all my students. the video shows a deadstick descent to landing which, without power, is virtually impossible to initiate negative G's. I'm sure you could dive, pick up a lot of airspeed and dump the stick forward, but even then the transition from dive to climb and dive again with no power would cause the airspeed to decay to where it would just become a descent again.
 

skyguynca

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Back to my Dad's take off.... I believe the 3 changes in pitch attitude may have been attempts at trim adjustments or feeling the stick pressure. They are definitely not negative G, and I don't see how they could have caused a significant change in the rotor rpm. I practice vertical descents from 1000-1500 AGL near the start of the runway into a "dive" to land on the 1,000 foot markers all the time, as seen in this video. Never seen significant rotor rpm decay. Next time I fly I will video the rotor rpm gauge as I lower the nose on a climb.
That is unlike your Dad's maneuvering, the throttle was never retarded, and pushing the stick forward while still under power will cause the rotor to unload. The rotor slowing was a few to 10"s of RPMs, coupled with the abruptness of the maneuver under power will cause blade flap.

I would never suggest you "try" the same maneuvers to test the outcome, plenty of people have already done that, hence the discussion in training to prevent such things.
 

Tyger

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I have estimated UK hours per machine accurately. I can find no reason to suppose the rest of the world is not in the same overall ballpark.
Just in terms of weather, I could easily imagine that many other countries have a lot more VFR/flyable hours than the UK during the course of the year.
 

Vance

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In the video it appears to be quite a sudden steep climb without an increase in power; perhaps a zoom climb.

Part of my airshow routine in The Predator is a zoom climb. It is my observation that the rotor slows down quickly as the top of the climb is approached because of projectile motion. The cyclic control becomes vague as the rotor rpm decreases. There is some information about projectile motion here: https://en.wikipedia.org/wiki/Projectile_motion

The Predator typically flies around 330 rotor rpm at air show weight and my personal minimum is 275 rotor rpm and maximum is 450 rotor rpm based on what I was told by Jim at Sport Copter. I have seen both.

I have used a g meter and I see .6Gs as I approach the top of a zoom climb.

If I sustained .6Gs my calculations suggest I would see 250 rotor rpm. The rotor would still provide some lift and some control. I don’t know at what rotor rpm and indicated air speed the rotor would become divergent.

In a steep climb the propeller thrust contributes to unloading the rotor.

In my opinion typically the retreating blade stalls and the advancing blade flies it into something.

I have also noticed that rapid cyclic movements slow the rotor.

I have not noticed a torque roll in The Predator if I leave in full power at the top of the zoom but the maneuver seems smoother if I reduce power at the top.

My 160 horsepower Lycoming is not geared so there is likely more torque at the propeller with the 915.

I did not notice a torque roll in the 915 powered AR-1 I flew in Texas but we were near maximum takeoff weight and the rotor was spinning pretty fast. The rotor tachometer was not working.

A light pilot flying the AR-1 solo would have a much lower rotor rpm to start with and torque roll might be more noticeable.

Given the direction of propeller rotation; torque roll in an AR-1 would be to the right.

Please understand I am not saying this is what happened, I am just trying to provide some information as to what I have experienced in similar circumstances to the video.

I am still puzzled by the remark about full right rudder.
 

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