Cabri crash at John Wayne Airport Sept 2018
An accurate appraisal, if you are in the business of building an aircraft primarily used for training then perhaps it should be a little forgiving for those that don't have the footwork of gene Kelly?
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In addition most of the instructors are used to fly helicopters with counter clockwise turning main rotors. The G2 is clockwise. Furthermore the fenestron has a different characteristic compared to a classic tail rotor. It's not linear but needs more pedal input for high power situations. The next factor is the moment provided by the tail fin itself. Slowing down you get to a point where the tail fin "stalls". At that moment you will need a big pedal input all of a sudden. That might even be more pronounced when turning into a left crosswind.
All these effects are common for all fenestron helicopters - they are not Cabri specific. Combined with the unusual direction due to the CW rotating rotor on the G2 it might be a surprise when you are not used to it.
I don't think it is a problem for a training heli, though. I learned on a Cabri and later transitioned to the EC135 and never had any problem with yaw control.
All these effects are common for all fenestron helicopters - they are not Cabri specific. Combined with the unusual direction due to the CW rotating rotor on the G2 it might be a surprise when you are not used to it.
I don't think it is a problem for a training heli, though. I learned on a Cabri and later transitioned to the EC135 and never had any problem with yaw control.
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In addition most of the instructors are used to fly helicopters with counter clockwise turning main rotors. The G2 is clockwise. Furthermore the fenestron has a different characteristic compared to a classic tail rotor. It's not linear but needs more pedal input for high power situations. The next factor is the moment provided by the tail fin itself. Slowing down you get to a point where the tail fin "stalls". At that moment you will need a big pedal input all of a sudden. That might even be more pronounced when turning into a left crosswind.
All these effects are common for all fenestron helicopters - they are not Cabri specific. Combined with the unusual direction due to the CW rotating rotor on the G2 it might be a surprise when you are not used to it.
I don't think it is a problem for a training heli, though. I learned on a Cabri and later transitioned to the EC135 and never had any problem with yaw control.
All these effects are common for all fenestron helicopters - they are not Cabri specific. Combined with the unusual direction due to the CW rotating rotor on the G2 it might be a surprise when you are not used to it.
I don't think it is a problem for a training heli, though. I learned on a Cabri and later transitioned to the EC135 and never had any problem with yaw control.
The fenestron isn't only on clockwise MR helicopters.
The concept that you 'have to get used to' differing MR direction and pedal inputs is, IMO, a furphy. If the nose needs to go left, push left pedal and if it needs to go right, push the right pedal. Those who overthink the issue are creating their own problem.
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With a grand total of 3 hours on fenestrons (2 on a G2, 1 on an EC130) and all the rest of my time on Robinsons, to me they felt like the proverbial chalk and cheese even though they can, properly operated, achieve the same things. I never noticed that the power pedal moved, but I sure did notice the substantial non-linearity of the fenestron. I quickly became friends with it in all regimes except entering and leaving the hover, where it's non-linearities still elude a proper programming in my muscle memory.
It's hard for me to say if the fenestron is intrinsically more difficult or if it just seems that way because I'm used to a plain old tail rotor. If one had never flown anything but a G2 "it is what it is". Indeed, one might be inclined to think that those who are transitioning from a tail rotor to a fenestron might be a bit more dangerous, so to speak, than someone who never knew anything but a fenestron.
I'd like to hear from someone who has experienced the opposite transition, i.e. learned on G2's and then found themselves in, say, a Robinson, and how it felt to go the other way, fenestron to tail rotor. My gut feel is that this is a lot easier than the reverse.
It's hard for me to say if the fenestron is intrinsically more difficult or if it just seems that way because I'm used to a plain old tail rotor. If one had never flown anything but a G2 "it is what it is". Indeed, one might be inclined to think that those who are transitioning from a tail rotor to a fenestron might be a bit more dangerous, so to speak, than someone who never knew anything but a fenestron.
I'd like to hear from someone who has experienced the opposite transition, i.e. learned on G2's and then found themselves in, say, a Robinson, and how it felt to go the other way, fenestron to tail rotor. My gut feel is that this is a lot easier than the reverse.
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Those who overthink the issue are creating their own problem.
"Lucky left/rotten right", as those on the west of the Atlantic are more used to, isn't always the case if the tail rotor goes round the "other" way, i.e. from left to right as you sit in the cockpit.
But this accident looks unusual, as if the little Cabri tripped over its own high heels!
Shy....perhaps you have not noticed....but there are wrong way turning Rotors in the USA along with the correct version.
Some of us are ambidextrous when it comes to Tail Rotor Systems over here.
Some of us are ambidextrous when it comes to Tail Rotor Systems over here.
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The fenestron isn't only on clockwise MR helicopters.
The concept that you 'have to get used to' differing MR direction and pedal inputs is, IMO, a furphy. If the nose needs to go left, push left pedal and if it needs to go right, push the right pedal. Those who overthink the issue are creating their own problem.
The concept that you 'have to get used to' differing MR direction and pedal inputs is, IMO, a furphy. If the nose needs to go left, push left pedal and if it needs to go right, push the right pedal. Those who overthink the issue are creating their own problem.
I also agree to just press the needed pedal to keep it straight. I never had a problem with that.
Nevertheless there might be habits for instructors that always trained on R22/R44 in situations like autos where trained movements kick in.
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But surely you haven't forgotten a certain thread where "Lucky Left/ Rotten Right" seemed to be talked about far too often for those of us used to instructing tail rotor malfunctions on helicopters where that advice was 180 degrees out...
As I've been trying to emphasise for over thirty years now, the "lucky" side, when it comes to dealing with reduced tail rotor control, is the retreating blade side. Easier to remember in a crisis if your short term memory runs as far back as watching the MR blades during the last rotor start. If anyone else would like it explaining further once again, I'd be very happy to do so.
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Judging by the missing trailing edges of the main rotor and the bent skids it does looks like a slightly crooked hard landing. Maybe they ran out of Nr near the bottom. Regardless, I'm glad they all walked away from that.
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HDG, For a start, read this (should be standard issue to every helicopter pilot):
https://publicapps.caa.co.uk/modalapplication.aspx?catid=1&pagetype=65&appid=11&mode=deta il&id=1127
The "Lucky Left / Rotten Right" saying was, I believe, coined in the USA, where traditionally the main manufacturers (e.g. Sikorsky) built all aircraft with counter clockwise main rotors.
It refers to a situation where tail rotor control is limited, such as a pedal jam or damaged tail rotor control system (note that I didn't include tail rotor drive failure). Basically, to safely land, the pilot needs to configure the aircraft on the approach so that the nose is "cocked off" to the "Lucky" side, i.e. LEFT in this case. As the collective is raised to cushion the landing, the increased main rotor torque reaction can be used to swing the nose of the aircraft to the right so it's briefly flying straight as the wheels/skids contact the ground, hopefully giving a good chance of avoiding a rollover. Additionally, to take advantage of the aerodynamic weather-cocking effect of the aircraft tail, arranging the approach with a crosswind on the "Lucky" side is also an advantage - certainly avoid a crosswind from the "rotten" side. It works!
However, the "Lucky Left / Rotten Right" only works for a counter-clockwise main rotor direction..... Anyone using that maxim in a helicopter with clockwise main rotors would be doing totally the wrong thing and would almost certainly lose control sooner or later.
I was involved in initial simulator trials in the mid 1980s, on behalf of the Helicopter Handling Sqn (Boscombe Down), to bring some sense to the lack of guidance given in the Puma HC1 FRCs and flight manual wrt to tail rotor malfunctions. This resulted in all RAF Puma pilots receiving tail rotor malfunctions simulator training from us. At least one RAF crew possibly later owed their lives to the training they received (their incident occurred over the North Sea and is included in the document in the link I posted above). It resulted in a successful ditching - despite the Puma HC1 having no flotation gear and I was told the aircraft was recovered almost intact.
Having realised later in my career after I had changed types a few times from aircraft with anti-clockwise to clockwise main rotor directions that I really shouldn't be remembering the "Lucky Left/ Rotten Right" saying in case "on the fateful day" I was flying a clockwise main rotor and got it wrong.
I thought about this for some time, then it struck me that the "Lucky" side is actually the retreating blade side, irrespective of the main rotor direction. I think I should be able to remember the blade rotation from the start up procedure.
https://publicapps.caa.co.uk/modalapplication.aspx?catid=1&pagetype=65&appid=11&mode=deta il&id=1127
The "Lucky Left / Rotten Right" saying was, I believe, coined in the USA, where traditionally the main manufacturers (e.g. Sikorsky) built all aircraft with counter clockwise main rotors.
It refers to a situation where tail rotor control is limited, such as a pedal jam or damaged tail rotor control system (note that I didn't include tail rotor drive failure). Basically, to safely land, the pilot needs to configure the aircraft on the approach so that the nose is "cocked off" to the "Lucky" side, i.e. LEFT in this case. As the collective is raised to cushion the landing, the increased main rotor torque reaction can be used to swing the nose of the aircraft to the right so it's briefly flying straight as the wheels/skids contact the ground, hopefully giving a good chance of avoiding a rollover. Additionally, to take advantage of the aerodynamic weather-cocking effect of the aircraft tail, arranging the approach with a crosswind on the "Lucky" side is also an advantage - certainly avoid a crosswind from the "rotten" side. It works!
However, the "Lucky Left / Rotten Right" only works for a counter-clockwise main rotor direction..... Anyone using that maxim in a helicopter with clockwise main rotors would be doing totally the wrong thing and would almost certainly lose control sooner or later.
I was involved in initial simulator trials in the mid 1980s, on behalf of the Helicopter Handling Sqn (Boscombe Down), to bring some sense to the lack of guidance given in the Puma HC1 FRCs and flight manual wrt to tail rotor malfunctions. This resulted in all RAF Puma pilots receiving tail rotor malfunctions simulator training from us. At least one RAF crew possibly later owed their lives to the training they received (their incident occurred over the North Sea and is included in the document in the link I posted above). It resulted in a successful ditching - despite the Puma HC1 having no flotation gear and I was told the aircraft was recovered almost intact.
Having realised later in my career after I had changed types a few times from aircraft with anti-clockwise to clockwise main rotor directions that I really shouldn't be remembering the "Lucky Left/ Rotten Right" saying in case "on the fateful day" I was flying a clockwise main rotor and got it wrong.
I thought about this for some time, then it struck me that the "Lucky" side is actually the retreating blade side, irrespective of the main rotor direction. I think I should be able to remember the blade rotation from the start up procedure.
I fully agree with Shy on the need to find one simple way of triggering the correct response by a Pilot enjoying a serious tail rotor malfunction.
I used "Left is good....Right is bad!" as a way when it comes to the American Standard.
That does not work of. course with the Patent avoiding French Standard.....which using my crutch would be "Right is good.....Left is bad!".
I adjusted my thinking to "More Power Pedal....Less Power Pedal." to accommodate the situation.
However one concocts a method that works and is easy to remember and implement is what is. needed.
Shy's method meets those requirements.
One thing is for sure....at a hover or an airspeed that below that required to facilitate streamlining the airframe during a loss of tail rotor thrust.....one better be able to correctly identify the problem and correctly apply the right technique.
In flight where there is plenty of airspeed....there usually is a bit more time to remember what kind of machine you are in as compared to the other situation.
I used "Left is good....Right is bad!" as a way when it comes to the American Standard.
That does not work of. course with the Patent avoiding French Standard.....which using my crutch would be "Right is good.....Left is bad!".
I adjusted my thinking to "More Power Pedal....Less Power Pedal." to accommodate the situation.
However one concocts a method that works and is easy to remember and implement is what is. needed.
Shy's method meets those requirements.
One thing is for sure....at a hover or an airspeed that below that required to facilitate streamlining the airframe during a loss of tail rotor thrust.....one better be able to correctly identify the problem and correctly apply the right technique.
In flight where there is plenty of airspeed....there usually is a bit more time to remember what kind of machine you are in as compared to the other situation.
I've been a pilot in the USA for many years, never heard these tail rotor sayings, "lucky left, rotten right" and what not before. At this point my pedal work is all subconscious anyway.
Just keep the nose straight
Just keep the nose straight
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Agreed. But as mentioned previously this type of low energy walk away roll over incident doesn't typically warrant NTSB Go Team involvement, so perhaps they are doing it for investigator training?
Last edited by givdrvr; 9th Sep 2018 at 19:38.
Robbiee....whqt kind of Tail Rotor Failure training have you had?
As long as things are working correctly your notion of "keeping the nose straight" is fine.....when that thing on the tail to malfunction or worse....then it gets a bit more difficult as you should well know by now.
Little simple things like knowing which way the nose of the aircraft moves in reaction to steady collective and throttle movement....or steady Main Rotor RPM but collective movement is also something one should know instinctively too.
As long as things are working correctly your notion of "keeping the nose straight" is fine.....when that thing on the tail to malfunction or worse....then it gets a bit more difficult as you should well know by now.
Little simple things like knowing which way the nose of the aircraft moves in reaction to steady collective and throttle movement....or steady Main Rotor RPM but collective movement is also something one should know instinctively too.