Cabri crash at John Wayne Airport Sept 2018

[John Eacott]

Flight instructor and student suffer minor injuries in helicopter crash (https://ktla.com/2018/09/03/2-suffer-minor-injuries-in-chopper-landing-at-john-wayne-airport-in-o-c/)


A flight instructor and student suffered minor injuries when their helicopter crash landed at John Wayne Airport in Orange County Monday afternoon, officials said.
The chopper could be seen tipped over on its side in a photo of the incident tweeted by O.C. Fire Authority. Fire officials responded to the crash site just after 3:30 p.m.
The two injured people were treated and refused to be taken for further medical treatment, according to fire officials. They were later identified as a flight instructor and student by Deeanne Thompson, a spokesperson for John Wayne Airport.
The aircraft was a Cabri G2 helicopter and it crashed along runway 20L at Taxiway J, according to John Wayne Airport (https://twitter.com/JohnWayneAir/status/1036762846946684929) officials. That runway is intended for smaller aircrafts and was shut down for about an hour an half as it was cleared of oil spilled during the crash, officials said.
The airport said the chopper was released for removal by National Transportation Safety Board officials at 4:10 p.m.
There's been no disruption to commercial flights, airport officials said. In photos of the scene, first responders could be seen lifting the chopper up with a crane.


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[Ascend Charlie]

"Is it dead yet?"
"Nah, better spray it again!"

[gulliBell]

Nah, it's not dead, it's just resting!

[Agile]

At first glance, look like it slid on the U bolts at the "landing gear / body attachment" or is it a fused junction on purpose. Another "nobody hurt" occupant safety point for the Cabri.

[Vertical Freedom]

Thank GOD it was a Cabri :ok:

[ShyTorque]

I didn't know they had a retractable undercarriage....

[Wiggins61]

Cabri prefers kipping on its back. Should of nailed it to the perch.

[Ascend Charlie]

No wonder it crashed, look at what the moths did to the rotor blades.

[SASless]

Runway for smaller aircrafts than the Cabri?

[JohnDixson]

The article reads that the Fire Dept. responded at 3:36 PM and the NTSB released the aircraft at 4:10 PM.
John Wayne said : “ That’ll be the day “, twice in “ The Searchers “.

[Spunk]

The article reads that the Fire Dept. responded at 3:36 PM and the NTSB released the aircraft at 4:10 PM.
I guess that means „pilot error admitted“

[Gordy]

I guess that means „pilot error admitted“
I have never known the NTSB to show up to a non-fatal rollover, they just delegate to the local FAA office to report the findings to them.

[givdrvr]

I am curious if the NTSB would respond because according to the article below, this is the third crash (including 3 fatalities) plus an FAA safety investigation, that Revolution Aviation has experienced in recent months?

LA Times article (http://www.latimes.com/socal/daily-pilot/news/tn-dpt-me-faa-investigation-20180206-story.html)

[Gordy]

I am curious if the NTSB would respond because according to the article below, this is the third crash (including 3 fatalities) plus an FAA safety investigation, that Revolution Aviation has experienced in recent months?


The role of the NTSB is to investigate accidents not companies. The FAA will be investigating the company.

[SASless]

It would seem the FAA Safety Investigation went well as they were still in operation.

[Biggles78]

Maybe it's just pining for the fiords. :}

[Arnie Madsen]

When I look at the picture I keep thinking someone forgot to properly fasten the skid assembly to the bottom of the fuselage ..... I cannot see any damage other than blades when it slipped on it's side

[Ascend Charlie]

Perhaps practicing tail jams, came in sideways but didn't straighten up before touchdown?

Or somebody forgot the girth strap before hopping into the saddle? Big fat instructor climbed in with rotor turning?

[Bell_ringer]

Many cabri accidents have resulted by losing the tail.
The fenestron doesn't sound like it works particularly well.

[Spunk]

The fenestron doesn't sound like it works particularly well.

It's not the Fenestron which doesn't work well. Most of the time it's the guy on the pedals who doesn't.

[Bell_ringer]

It's not the Fenestron which doesn't work well. Most of the time it's the guy on the pedals who doesn't.

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?

[Spunk]

I wasn‘t referring to the student pilots in this world but to the flight instructors who are not ahead of the aircraft and/or their students.

[EDML]

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.

[John Eacott]

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.


The fenestron isn't only on clockwise MR helicopters.


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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.

[aa777888]

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.

[Vertical Freedom]

Many cabri accidents have resulted by losing the tail.
The fenestron doesn't sound like it works particularly well.

Hey BR...........the G2 works great, with the same performance limitations of any Fenestron; but the greatest limiting faktor is, yep You guessed it, it's the Pilot :ugh:

[krypton_john]

EC145T2 in #24 clearly owned by a lawyer....

[arketip]

EC145T2 in #24 clearly owned by a lawyer....

:ok::D .

[Aesir]

EC145T2 in #24 clearly owned by a lawyer....

:D Good catch, haha

[ShyTorque]

Those who overthink the issue are creating their own problem.

True enough if everything is working normally, but if faced with a tail rotor control problem - then it is best to have thought it through in advance.
"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!

[SASless]

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.

[EDML]

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.

Also flying the EC135 I know that there are CCW Helis with fenestron as well.

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.

[ShyTorque]

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.

Of course I'd noticed; the clue is in the words I wrote.

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.

[Helicopterdriverguy]

Go on then please explain shy

[cattletruck]

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.

[ShyTorque]

Go on then please explain shy


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=detail&id=1127 (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.

[SASless]

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.

[Robbiee]

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 :)

[givdrvr]

The role of the NTSB is to investigate accidents not companies. The FAA will be investigating the company.
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?

[SASless]

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.

[krypton_john]

Also flying the EC135 I know that there are CCW Helis with fenestron as well.

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.
Yes but that's reactive.
If you like to be proactive and anticipate a correction before it's required, you need to follow the lucky left mantra (or whatever works for your particular machine)

[Vertical Freedom]

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=detail&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.

Crickey ST....it's painful to see so much confusion said Confucius; lucky left & rotten right what the Banana peel is that? We are Helicopter Pilots not Brain Surgeons. use the trusted KISSS principal; Keep it Simple, Smart & Safe who cares which way the MR turns if the nose goes left You apply right pedal & the reverse for nose going right! 'Fly the Picture' Mission accomplished. That is all I tell Students & that's all they need to know, anything more becomes a complicated head-spin which ain't required. :8 Ow & wind towards the power pedal side, end of story. Yep reckon that about does it......Beer o'oclock :D

[SASless]

:8 Ow & wind towards the power pedal side, end of story.

Is that your Memory aid such as "Lucky Left......"?

Very appropriate and simple for sure! (For US style machines anyway.)

How does one "Wind towards the Power Pedal in a French Machine?

[ShyTorque]

That is all I tell Students & that's all they need to know, anything more becomes a complicated head-spin which ain't required.


I'm not confused but I've seen many others who have been. Your advice is similar to the almost total lack of advice given to RAF helicopter pilots (such as I was back then) forty years ago.

If that's all you teach your students, one of them will possibly one day come badly unstuck. Problem is, once you have lost tail rotor control, how do you work out which is (or rather was), "power pedal".

[Vertical Freedom]

Is that your Memory aid such as "Lucky Left......"?

Very appropriate and simple for sure! (For US style machines anyway.)

How does one "Wind towards the Power Pedal in a French Machine?

Reworded for the French; 'Lucky Right' :O or simply put: Wind to the power pedal side works on all rotational camps :8

[Vertical Freedom]

I'm not confused but I've seen many others who have been. Your advice is similar to the almost total lack of advice given to RAF helicopter pilots (such as I was back then) forty years ago.

If that's all you teach your students, one of them will possibly one day come badly unstuck. Problem is, once you have lost tail rotor control, how do you work out which is (or rather was), "power pedal".

G'day ST............Yep I have lost one Student, but I knew prior to him passing the flight test that he was an accident waiting to happen. I warned the ATO but he politely told me that if he gives a tick in all boxes, he passes, which he did...2 years later crashed & burned, no pax just him, RIP. Yep there is more these buggers need to learn, the entire CPL syllabus with Mountain flying I hadn't posted here. & if ole Mate was flying with power on before he lost tail-rotor control, surely his/her memory may just stretch that far back to remember which the power pedal was :cool: otherwise a big post-it note on the forehead might also work :eek:

[Robbiee]

I'm quite glad I never got into this "lucky left" mantra thing. I mean say you're slowing on a photo flight in the R44 and you find yourself at full throttle, but not really paying attention (as in a number of R44 accidents I've read about) you push in "lucky left" and things are gonna get "rotten" pretty quick!

As for wind. If I had stuck left pedal in the R44, I think I'd rather have the wind on my right.

[RMK]

I' Problem is, once you have lost tail rotor control, how do you work out which is (or rather was), "power pedal".

With a counter-clockwise rotor (i.e. US makes), you point your index finger down while holding the collective (like your making a gun with your hand) and point your finger left to yaw left and right to yaw right. It works and is easier to remember than decrease throttle for left and increase throttle for right.

[Vertical Freedom]

With a counter-clockwise rotor (i.e. US makes), you point your index finger down while holding the collective (like your making a gun with your hand) and point your finger left to yaw left and right to yaw right. It works and is easier to remember than decrease throttle for left and increase throttle for right.

Hey RMK.....that's spot on Mate, & certainly discussion points during training as well as a practical :ok: unfortunately some French turbines have a clunk full noise or idle on the twist grip so Your power on for flight or idle/auto, nuttin in-between ie: AS350B3+/eB4, H125, H130T2, I'm sure there's more! :( Makes tail-rotor problems a nightmare where luck is needed & following her around with cyclic during the run on when she spears off the line You'd pegged :eek:

[EDML]

Yes but that's reactive.
If you like to be proactive and anticipate a correction before it's required, you need to follow the lucky left mantra (or whatever works for your particular machine)

True. I try to fly reactive as much as possible. It makes transition between CW and CCW a lot easier. Obviously that will not work in a situation like a hover auto.

[ShyTorque]

With a counter-clockwise rotor (i.e. US makes), you point your index finger down while holding the collective (like your making a gun with your hand) and point your finger left to yaw left and right to yaw right. It works and is easier to remember than decrease throttle for left and increase throttle for right.

But that only works if you fly a helicopter with a throttle on the collective. Most larger, turbine engined types do not have that advantage. What is your advice for a turbine engined helicopter with a speed select lever on the overhead panel?

[nigelh]

Realistically the power reduction needed for loss of t/r thrust will come from collective and not throttle?
i can’t see winding off throttle but not reducing collective ending well . There may be an option to do a shallow approach and use throttle in a 206 , MD500 or even some AS350,s but for the rest of us it’s not really an option. I may be quite wrong but I would prefer to auto ( throttle on ) onto a bad site rather than lose control trying to fly on .... obviously if I was over v hostile territory I may be forced to give it a go and try to keep flying if possible ( this would probably depend on the airspeed you have when it occurs ... my guess is anything much less than 50 knots it’s going to be hard not to start to spin )
i wouid be interested to hear what other people think !
would you for instance use throttles on an old 109 or 355 by letting go off collective for a second ?? Wouid co pilot do this ??!!

[gulliBell]

Correct, as the initial memory action. Collective will take away most of the torque (to maintain control), throttle will take away the rest of the torque (for landing, do this prior to touchdown). If the throttle is not on the collective, perfectly OK to take your hand off the collective at the point in time you need to pull off the throttle. If you can't do that you shouldn't be flying in the 1st place.

[SASless]

Robbiee......perhaps you might consider alternative employment young fellow.

[WillyPete]

When I look at the picture I keep thinking someone forgot to properly fasten the skid assembly to the bottom of the fuselage ..... I cannot see any damage other than blades when it slipped on it's side

They all do that on side impacts.
There's a few other images of cabri crashes and all the ones that impacted sideways show the same thing.

[Reely340]

Realistically the power reduction needed for loss of t/r thrust will come from collective and not throttle?




Agree, that's how I was told. Stuck TR w/o churning noise:
Pick an airstrip within reach for a +40kts run-on landing, eating away all the landing gear glide pads.:O
Lacking an airstrip pick a "wide", straigth and level back country road. :ooh:
Lacking a suitable road pick a flat, level meadow. :cool: This is where throttle control becomes important because roll-over dwells close by:
while zipping through grass at 1 ft AGL pitch up is nose to the right (e.g. bad) pitch down is nose to the left, wind from 11 'o clock preferred.
The key is to really have a very long stretch of grass (doh) and to approach ground inch by inch, keeping skids in parallel with trajectory by pitch control just described.
This is how I have to annually demonstrate "stuck TR landings", as the ATO would like to preverve carbid skid protectors' life.
So we do a couple of super shallow final approaches to an imaginary line some 30 yards off the centerline into the grass, till full stop, w/o touching them pedals.

Stuck TR accompanied by grinding noise or worse ("land immediately"), or hostile ground (in this case less than half a mile of level grass) as far as one's remaining fuel can reach
would command an AR landing. :uhoh: I'm pretty sure during the very end, right after the flare, I'd be facing ugly spinning, although an unpowered MR "should" not create any torque on the fuselage.

Are these concepts about right, for a S300C?

note: I must admitt never to have been demonstrated let alone done myself a landing with the TR stuck at 100% or 100%. :ouch: Does this happen in real life?
For what AoA will the TR blades settle, when the TR control rod breaks/unscrews, leaving the TR pitch mechanism "freewheeling" w/o any control input?

[ShyTorque]

Reely,
For what AoA will the TR blades settle, when the TR control rod breaks/unscrews, leaving the TR pitch mechanism "freewheeling" w/o any control input?


That question illustrates my earlier point about training. It's also about knowing your aircraft. What happens on "your" aircraft depends on aircraft design and the type of failure. Some (e.g. Sikorsky) have a tail pitch centreing mechanism of some sort (normally spring loaded) so in the event of a flying control disconnection the tail blades will adopt a pre-set mid position which should allow a known flight configuration to be flown to a landing. Other types don't have such a mechanism so the tail rotor blade pitch could go anywhere, depending on the failure mode.

There is a lot of advice in the CAA document I linked to earlier.

[Reely340]

Reely,


That question illustrates my earlier point about training. It's also about knowing your aircraft. What happens on "your" aircraft depends on aircraft design and the type of failure. Some (e.g. Sikorsky) have a tail pitch centreing mechanism of some sort (normally spring loaded) so in the event of a flying control disconnection the tail blades will adopt a pre-set mid position which should allow a known flight configuration to be flown to a landing. Other types don't have such a mechanism so the tail rotor blade pitch could go anywhere, depending on the failure mode.
Well, from my routine wiggling of the control rod during pre-flight inspection I could assure they'll stay put whereever I set them,statically.
What no person could assure me of is if they are designed to go for an emergency friendly "neutral" AoA while turning, w/o control input.

There is a lot of advice in the CAA document I linked to earlier. Error 404. Pls always copy/past the document's title wehn posting a link, as web-site operators typically do not care if their redesign #2032 has broken URLs.

[tottigol]

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?
Aaand that would be the Robinson family of helicopters?

[gulliBell]

@Reely340 I don't follow much of what you said at #56, despite reading it a few times.

[gulliBell]

@ShyTorque at #57 : that's right. Some S76 trainees wouldn't even know they've had a TR control cable failure until they're about to land and suddenly find to their surprise that things start to go a bit whacky for them. TR fixed pitch or control cable failure malfunctions should all be a non-event in the S76, assuming you have the fuel to fly to a suitable runway. Loss of TR thrust however is a big deal in the S76, as it is in all helicopters.

[[email protected]]

Gulli - I think what reely is suggesting is to fly a shallow approach maintaining enough speed to retain directional control using roll (ie enough flow over the tail to keep it providing some anti-tq thrust) but with a wind from the power-pedal side so you are cocked off the 'runway' heading to that side.

Then, once very close to the ground (so you can land it quickly when the nose swings around) gradually reduce speed, replacing it with power (hopefully reduced because you are well into ground effect).

As you get to the critical speed for your stuck pedal position, land the aircraft carefully (without slamming the lever down), usually a small forward cyclic input, and carry out a fast running landing using the friction of the skids to keep you straight and slow you down.

The higher your stuck TR pitch, the lower your touch down speed shoudl be. You can carry out a handling check at a safe height to assess your likely runon speed but it should be done very gently and with enough height to dive on speed should you go below your critical speed by accident.

[Robbiee]

Aaand that would be the Robinson family of helicopters?

A delightful bit of irony that Robinson's weren't designed for training and have excellent tailrotors that anyone can easily master.

[gulliBell]

I still don't get it. You don't need to touch the throttle on stuck pedal. Leave it at fly. And throughout the manoeuvre the collective position is controlling yaw, yaw is not controlled by pitch. Pitch controls airspeed. His explanation sounds all whacky to me. Unless the technique is specific to a helicopter type I'm unfamiliar with.

[Reely340]

@Reely340 I don't follow much of what you said at #56, despite reading it a few times.No biggie.
I just relayed my "concept" of how to react to TRCF depending on the circumstances it hits you,
and learn from the (corrective) feedback from PPRUners with experience.

But then again that is way OT in a Cabri thread, so I'll shut up and listen. ;)

[gulliBell]

If the TR fixed pitch position was 100% (which I assume you mean stuck full left pedal), then it's your unlucky day. Think about it. If the TR is stuck with more left pedal than what it takes to hover IGE then it's going to get messy at the bottom (it won't be possible to get or keep it straight because using more than hover power to get it straight is just going to shoot you back up into the air). I never practice stuck left pedal when the pedal is forward of the hover position.

All TR control malfunctions the landing technique is basically the same. For loss of drive to TR the technique is always autorotation with the engine off before the bottom.

[SASless]

Gulli......ever use the Throttle to reduce Nr to the bottom of the green arc....or even a bit lower when dealing with a "Stuck Left" situation?

The problem you described is simply an excess of amount of Tail Rotor Thrust.....slow down the Tail Rotor and you reduce the amount of thrust it is putting out.

You can do that in forward flight as well to reduce the amount of side slip angle and determine if you can control the aircraft at slower speeds.

Stuck Left Pedal situations are straight forward.....as compared to "stuck right/no tail rotor thrust or thrust pushing the nose off center to the right (American Standard Rotor System).

[Bell_ringer]

An alternative technique is to label each pedal with the pprune rotorheads URL. If the moment arrives,remove the phone from your pocket, enter the URL and read the appropriate guidance for your situation. :}

[[email protected]]

You beat me to it Sasless:ok:

[nigelh]

I think most T/rotors have small weights which by centrifugal force put some pitch onto the blades so you would get “ some “ compensation from torque if they disconnect. Not saying this for fact so shoot me down if I’m wrong!!

[ShyTorque]

Well, from my routine wiggling of the control rod during pre-flight inspection I could assure they'll stay put whereever I set them,statically.
What no person could assure me of is if they are designed to go for an emergency friendly "neutral" AoA while turning, w/o control input.

Error 404. Pls always copy/past the document's title wehn posting a link, as web-site operators typically do not care if their redesign #2032 has broken URLs.

Reely, My apologies - the website looks like it has been changed since I posted the link!
The link should take you to a page on the CAA website where a free of charge .PDF copy of the following can be obtained:

Reference:CAA Paper 2003/01
Title:Helicopter Tail Rotor Failures

I think if you search for that on Google you should find it.

[SASless]

Crab,

There is an amazing lack enthusiasm when it comes to tail rotor malfunction training.

I loved it!

My training by thevUS Army andafterwards was excellent.

But back then it needed to be as for various reasons it was a frequent occurrence to experience sudden malfunctions.

We also needed to fly with thebmalfunctions if possible due to the hostile folks in the neighborhood.

[gulliBell]

.....ever use the Throttle to reduce Nr to the bottom of the green arc....

Yeah, double DECU in a C++ but not because of a TR problem. However that's not touching the throttle at all, it's touching the engine trim. But yeah, doing something to change NR however so.

In something else, I'm not sure bottom of the green would overcome a left pedal on the stops.

[[email protected]]

Gullibell - left pedal on the stops would be a pretty extreme condition but even then, reducing the Nr might make the difference between a controlled(ish) landing and a rollover.

Sasless - agreed TR malfunctions are great fun but best practised in the sim. We did plenty on the 365 in the aircraft and 40-50kt running landings certainly got the student's attention!

[gulliBell]

Well yeah, of course. The guy did ask about "100%" stuck pedal which I took to mean full left on the stops. Rather than binding in a pedal where you have some movement and control response. It's not something I have ever practiced because it's beyond the realms of imagination of anything I'm familiar with.

And I suppose we are talking about simple helicopters, and not those where you can't adjust the RRPM.

[SASless]

I I'm not sure bottom of the green would overcome a left pedal on the stops.

Green Lines, Green Arcs....are for Normal Operations.

What part of a tail rotor malfunction falls under that category?

Huey's fly at 5800 RPM with your Collective up under your arm and a built in right turn during takeoff....instead of the normal 6600 RPM (Engine RPM).

Why would you stop at the bottom of the Green Normal Operations limit if you needed to reduce the Tail Rotor Thrust in order to make a somewhat normal approach to a low hover landing?

The method works on any helicopter where the pilot can control the Nr either by hand throttle or Power lever.

[gulliBell]

Because you mentioned bottom of the green in #67, I was just continuing with that thought.